The Vascular Plants of Iowa

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• Iowa and Its Flora
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Abies balsamea (L.) Miller
Rare northeast: Allamakee County, Clayton County, Howard county and Winneshiek county

Abutilon theophrasti Medicus
Common throughout

Acalypha gracilens Gray [incl. var. monococca Engelm.]
Rare east: Benton County, Buchanan County, Jones county, Lee county, Muscatine county and Wapello county 1938

Acalypha ostryifolia Riddell
Rare southwest: Fremont county 1940 and Pottawattamie county 1949

Acalypha rhomboidea Raf.
Common east, north central and south central; infrequent elsewhere

Acalypha virginica L.
Common south; infrequent east; rare northwest

Acer ginnala Maxim.
Infrequent escape from cultivation

Acer negundo L.
Common throughout

Acer nigrum Michx. f.
Common eastern two-thirds, except rare southeast

Acer rubrum L.
Rare northeast: Allamakee County; widely cultivationivated

Acer saccharinum L.
Common throughout

Acer saccharum Marsh.
Common east

Acer spicatum Lam.
Rare northeast: Allamakee County, Clayton County, Dubuque county and Winneshiek county

Achillea millefolium L. ssp. lanulosa (Nutt.) Piper
Common throughout

Aconitum noveboracense Gray
Rare central, northeast and east central: Allamakee County, Clayton County, Delaware County, Dubuque county, Hardin county and Jackson county

Acorus calamus L.
Frequent central and in lakes area; rare west and extreme northeast

Actaea pachypoda Ell.
Frequent to common eastern half and central; rare southwest

Actaea rubra (Aiton) Willd.
Rare southeast and south central; frequent to common elsewhere

Adiantum pedatum L.
Rare northwest; frequent north central; common elsewhere

Adlumia fungosa (Aiton) Greene
Rare east central: Benton County 1910

Adoxa moschatellina L.
Rare central, northeast and east central

Aegilops cylindrica Host
Rare central, south central and southwest: Boone County, Decatur County, Mahaska county 1938 and Taylor county 1942

Aesculus glabra Willd. [incl. var. arguta (Buckley) Robinson]
Common southeast and south central; infrequent southwest; infrequent escape from cultivation north central

Aesculus hippocastanum L.
Occasional escape from cultivation throughout

Agalinis aspera (Douglas ex Bentham) Britton
Frequent in Iowan Surface and southwest; infrequent northeast; rare northwest

Agalinis gattingeri (Small) Small
Rare central, east central, southeast and south central: Decatur County 1903, Henry county n.d., Jefferson county 1935, Jones county, Lee county, Muscatine county and Webster county 1908

Agalinis paupercula (Gray) Britton
Infrequent to rare north central and east; rare southwest: Pottawattamie county 1898

Agalinis purpurea (L.) Pennell
Absent southeast and south central; infrequent to rare elsewhere

Agalinis skinneriana (Wood) Britton
Rare northeast and southeast: Allamakee County, Dubuque county and Muscatine county 1922

Agalinis tenuifolia (Vahl) Raf. [incl. var. macrophylla (Bentham) Blake; var. parviflora (Nutt.) Pennell]
Infrequent northeast and southeast; rare northwest; common elsewhere

Agastache foeniculum (Pursh) Kuntze
Rare central, northwest and northeast: Clay County, Clayton County 1933, Dickinson county, Emmet county, Lyon county and Story county 1948

Agastache nepetoides (L.) Kuntze
Frequent south central; infrequent to rare elsewhere

Agastache scrophulariifolia (Willd.) Kuntze
Common north central; infrequent to rare elsewhere

Agrimonia eupatoria L.
Rare central: Story county 1907

Agrimonia gryposepala Wallr.
Infrequent southern half and north central; frequent to common elsewhere

Agrimonia parviflora Aiton
Frequent southeast; infrequent south central

Agrimonia pubescens Wallr.
Infrequent northwest and north central; frequent to common elsewhere

Agrimonia striata Michx.
Infrequent to rare throughout

Agropyron cristatum (L.) Gaertner
Rare escape central and west; planted for erosion control

Agropyron intermedium (Host) Beauv.
Rare escape from experimental plantings in central and southeast: Keokuk county and Story county

Agropyron pectiniforme R. & S.
Rare escape from cultivation in west central, northwest and northeast: Allamakee County, Monona county, Plymouth county and Woodbury county

Agropyron repens (L.) Beauv.
Common throughout

Agropyron repens X A. trachycaulum
Rare northern quarter of state

Agropyron smithii Rydb.
Infrequent northeast and east central; frequent to common elsewhere

Agropyron trachycaulum (Link) Malte [incl. var. unilaterale (Vasey) Malte]
Frequent to common north; infrequent to rare southeast and south central

Agrostemma githago L.
Rare weed in eastern two-thirds; last collected in 1925

Agrostis gigantea Roth
Common throughout

Agrostis hyemalis (Walter) BSP.
Frequent east; infrequent to rare west

Agrostis hyemalis (Walter) BSP. var. tenuis (Tuckerman) Gl.
Frequent northern half; rare southeast; absent elsewh

Agrostis perennans (Walter) Tuckerman
Frequent south; infrequent to rare north

Agrostis stolonifera L. var. palustris (Hudson) Farw.
Rare escape from golf greens

Ailanthus altissima (P. Miller) swingle
Frequent in southern half, spreading from cultivation

Alcea rosea L.
Common throughout most of state

Alisma gramineum J. G. Gmelin
Rare west central: Greene county

Alisma plantago-aquatica L. [incl. var. americanum Schultes; var. parviflorum (Pursh) Torrey]
Common in most of state

Alliaria petiolata (Bieb.) Cavara & Grande
Rare: scattered localities, rapidly increasing its range

Allium canadense L.
Frequent to common throughout

Allium cernuum Roth
Rare in Paleozoic Plateau

Allium mutabile Michx.
Rare northeast: Black Hawk County

Allium porrum L.
Rare southwest: Mills county

Allium stellatum Nutt. ex Ker-Gawl.
Frequent to common northwestern quarter; rare northeast

Allium tricoccum Aiton [incl. var. burdickii Hanes]
Frequent to common northeast; infrequent elsewhere

Allium vineale L.
Rare in east central and south, spreading rapidly

Alnus rugosa (Du Roi) Sprengel
Rare northeast

Alopecurus aequalis Sobol.
Common in lakes area; infrequent to rare elsewhere

Alopecurus carolinianus Walter
Infrequent south; rare northwest and northeast

Alopecurus pratensis L.
Rare central and north central: Hancock county and Story county

Alyssum alyssoides (L.) L.
Rare west central, northwest and east central: Emmet county 1927, Dickinson county, Johnson county 1919 and Monona county 1932

Amaranthus albus L.
Rare northwest; frequent to common elsewhere

Amaranthus arenicola I. M. Johnston
Rare west central, northwest and southeast: Guthrie county, Muscatine county 1895 and Palo Alto county 1935

Amaranthus groecizans L.
Rare in Iowan Surface; frequent to common elsewhere

Amaranthus hybridus L.
Rare northeast and southwest; infrequent southeast

Amaranthus powellii S. Watson
Rare northwest: Clay County and Palo Alto county

Amaranthus retroflexus L.
Frequent to common throughout

Amaranthus rudis Sauer
Infrequent to frequent throughout

Amaranthus spinosus L.
Rare southeast: Keokuk county and Lee county 1925

Amaranthus tuberculatus (Moq.) Sauer
Frequent to common southeast; infrequent north central and northeast; rare south central

Ambrosia artemisiifolia L. [incl. var. elatior (L.) Descourt.]
Common throughout

Ambrosia bidentata Michx.
Rare southeast and south central: Jefferson county, Monroe county 1949 and Van Buren county

Ambrosia psilostachya DC. [incl. var. coronopifolia (T. & G.) Farw.]
Common southwest and in Loess Hills; infrequent to rare elsewhere

Ambrosia trifida L.
Common throughout

Amelanchier alnifolia Nutt.
Rare northwest and north central: Dickinson county, Emmet county, Hancock county and Lyon county

Amelanchier arborea (Michx. f.) Fern.
Infrequent northeastern quarter; absent northwest; frequent elsewhere

Amelanchier humilis Wieg.
Frequent north central and in Paleozoic Plateau; rare in Iowan Surface

Amelanchier interior Nielsen
Frequent in Paleozoic Plateau; rare extreme east

Amelanchier sanguinea (Pursh) DC.
Rare north, central and east central

Ammannia coccinea Rottb.
Common southwest; infrequent to rare elsewhere; no records from Paleozoic Plateau

Ammannia robusta Heer & Regel
Rare south

Amorpha canescens Pursh
Common throughout

Amorpha fruticosa L. [incl. var. angustifolia Pursh]
Frequent to common throughout most of state

Amorpha nana Nutt.
Rare central, north, and south central

Ampelopsis cordata Michx.
Rare southeast and southwest: Fremont county 1898 and Lee county

Amphicarpaea bracteata (L.) Fern. [incl. var. comosa (L.) Fern.]
Frequent to common throughout

Anagallis arvensis L.
Rare central and east central: Johnson county, Scott county 1886 and Story county

Anaphalis margaritacea (L.) Bentham & Hooker
Rare northeast and east central: Black Hawk County 1892, Clayton County 1924, Fayette county ca. 1897 and Linn county 1933

Anchusa azurea Miller
Rare west central and northwest: Carroll County, Dickinson county 1928

Andropogon gerardii Vitman
Common throughout

Andropogon hallii Hackel
Rare west central and southeast: Louisa county, Muscatine county and Woodbury county

Andropogon virginicus L.
Rare southeast

Androsace occidentalis Pursh
Frequent north central and extreme east; infrequent to rare elsewhere

Anemone canadensis L.
Frequent extreme east and south central; common elsewhere

Anemone caroliniana Walter
Frequent in Des Moines lobe; infrequent to rare elsewhere

Anemone cylindrica Gray
Common northwestern half; infrequent to rare elsewhere

Anemone quinquefolia L. [incl. var. interior Fern.]
Common northeast and in Paleozoic Plateau; infrequent extreme east and central; rare southeast and south central

Anemone virginiana L.
Frequent south central; infrequent northwest; common elsewhere

Angelica atropurpurea L.
Rare north central and east

Antennaria neglecta Greene
Infrequent southwest; frequent to common elsewhere

Antennaria plantaginifolia (L.) Richardson
Rare to infrequent southwest; common elsewhere

Anthemis arvensis L.
Rare central: Poweshiek county and Webster county 1903

Anthemis cotula L.
Frequent to common throughout

Anthemis tinctoria L.
Rare northeast: Clayton County 1929

Anthyllis vulneraria L.
Rare central and north central: Story county and Wright county, last collected in 1935

Apios americana Medicus
Absent northwest; rare in Iowan Surface; frequent to common elsewhere

Aplectrum hyemale (Muhl. ex Willd.) Torrey
Infrequent to rare central and east

Apocynum androsaemifolium L.
Common northeast; rare northwest; infrequent elsewhere

Apocynum cannabinum L. [incl. var. pubescens (Mitchell) A. DC]
Frequent to common throughout

Apocynum sibiricum Jacq. [incl. var. cordigerum (Greene) Fern.]
Frequent to infrequent throughout

Apocynum X medium Greene
Frequent southeast

Aquilegia canadensis L. [incl. var. coccinea (Small) Munz]
Frequent south central and southwest; common elsewhere

Arabis canadensis L.
Common in Paleozoic Plateau; infrequent to frequent elsewhere

Arabis divaricarpa A. Nelson
Rare central, northwest, northeast and east central: Delaware County 1919, Dubuque county 1922, Emmet county 1927, Johnson county, Jones county and Webster county 1903

Arabis drummondii Gray
Infrequent east; rare south central

Arabis glabra (L.) Bernh.
Rare northeast, extreme east and south central

Arabis hirsuta (L.) Scop. [incl. var. pyenocarpa (M. Hopk.) Roll.; var. adpressipilis (M. Hopk.) Roll.]
Infrequent to rare throughout

Arabis laevigata (Muhl. ex Willd.) Poiret
Infrequent northeastern quarter; rare southeast

Arabis lyrata L.
Common in Paleozoic Plateau; infrequent to rare rest of northeast, east and south central

Arabis missouriensis Greene
Rare northeast: Allamakee County

Arabis shortii (Fern.) Gl.
Infrequent to rare throughout

Aralia nudicaulis L.
Frequent to common north central and northeast; infrequent to rare elsewhere

Aralia racemosa L.
Frequent eastern half; infrequent to rare western half

Arctium lappa L.
Rare north central and southeast: Des Moines county and Floyd county

Arctium minus Bernh.
Frequent to common throughout

Arctium tomentosum Miller
Rare northwest: Emmet county 1923

Arctostaphylos uva-ursi (L.) Sprengel
Rare northeast: Fayette county and Winneshiek county 1930

Arenaria serpyllifolia L.
Rare northwest: Emmet county 1929

Argemone albiflora Hornem.
Rare west central, east central and southeast: Iowa county 1927, Louisa county and Sac county 1923

Argemone mexicana L.
Rare southeast: Henry county 1897 and Muscatine county 1896

Argemone polyanthemos (Fedde) G. Ownbey
Rare northwest: Plymouth county

Arisaema dracontium (L.) Schott
Rare to infrequent northeast; frequent south; rare in lakes area

Arisaema triphyllum (L.) Schott
Common throughout

Aristida basiramea Engelm. ex Vasey
Infrequent to rare throughout

Aristida curtissii (Gray) Nash
Common extreme northwest; infrequent to rare elsewhere

Aristida dichotoma Michx.
Infrequent southeast; rare southwest, and in northwest: Lyon county 1949

Aristida longespica Poiret
Rare southeast

Aristida longespica Poiret var. geniculata (Raf.) Fern.
Infrequent southern half; rare northwest: Lyon county and Palo Alto county

Aristida oligantha Michx.
Common southern half; rare northern half

Aristida purpurea Nutt. var. longiseta (Steudel) Vasey
Rare northwest

Aristida ramosissima Engelm. ex Gray
Rare southeast: Henry county 1894

Aristida tuberculosa Nutt.
Infrequent to rare eastern quarter

Aristolochia serpentaria L.
Rare southeast: Henry county, Lee county, and Muscatine county 1897

Armoracia aquatica (Eaton) Wieg.
Rare east central, southeast and southwest: Muscatine county 1894, Scott county pre-1900 and Union county 1882

Armoracia rusticana (Lam.) Gaertner, Meyer & Schreber
Rare escape from cultivation throughout

Aronia melanocarpa (Michx.) Ell.
Rare northeast: Winneshiek county

Arrhenatherum elatius (L.) Presl
Rare escape from cultivation in central, northwest, east central and southwest: Dickinson county, Marshall county, Page county, Scott county and Story county

Artemisia abrotanurn L.
Rare southeast: Muscatine county 1892

Artemisia absinthium L.
Rare northwest: Sioux county

Artemisia annua L.
Rare southeast and south central

Artemisia biennis Willd.
Infrequent to rare throughout

Artemisia campestris L. ssp. caudata (Michx.) Hall & Clem.
Rare to infrequent west and south; frequent to common elsewhere

Artemisia dracunculus L.
Infrequent to rare throughout

Artemisia frigida Willd.
Rare northwest: Lyon county

Artemisia ludoviciana Nutt. [incl. var. gnaphalodes (Nutt.) T. & G.]
Frequent to common throughout

Artemisia serrata Nutt.
Rare eastern two-thirds

Artemisia vulgaris L.
Rare northeast and east central: Delaware County, Scott county late 1800's

Aruncus dioicus (Walter) Fern. [incl. var. pubescens (Rydb.) Fern.]
Rare east: Clinton County, Des Moines county, Dubuque county, Jackson county, Lee county and Muscatine county

Asarum canodense L. [incl. var. acuminatum Ashe; var. reflexum (Bickn.) B. L. Robinson]
Common eastern two-thirds; frequent southwest; rare northwest

Asclepias amplexicaulis Smith
Frequent east; rare to infrequent elsewhere

Asclepias engelmanniana Woodson
Rare west central and southwest: Monona county and Pottawattamie county

Asclepias exaltata L.
Frequent in Paleozoic Plateau; rare elsewhere

Asclepias hirtella (Pennell) Woodson
Not reported central and west; infrequent to rare elsewhere

Asclepias incarnata L.
Frequent to common throughout

Asclepias lanuginosa Nutt.
Rare northern half and Muscatine county

Asclepias meadii Torrey ex Gray
Rare east central and south: Adams County 1899, Adair County, Clarke County, Decatur County, Scott county 1889 and Warren county

Asclepias ovalifolia Dene.
Rare to infrequent north

Asclepias purpurascens L.
Infrequent to rare throughout

Asclepias quadrifolia Jacq.
Rare central and south central; infrequent southeast

Asclepias speciosa Torrey
Infrequent to rare western half

Asclepias stenophylla Gray
Rare west central and northwest: Guthrie county, Plymouth county and Sioux county

Asclepias sullivantii Engelm. ex Gray
Infrequent to rare throughout most of state; apparently absent northeast and east central

Asclepias syriaca L.
Common throughout

Asclepias tuberosa L. ssp. interior Woodson
Infrequent to frequent throughout

Asclepias verticillata L.
Common throughout

Asclepias viridiflora Raf.
Frequent to common western half; infrequent to rare eastern half

Asimina triloba (L.) Dunal
Rare east central, southeast and southwest: Clinton County, Des Moines county, Fremont county, Jackson county, Lee county, Louisa county, Taylor county and Van Buren county

Asparagus officinalis L.
Frequent to common escape from cultivation

Asplenium platyneuron (L.) Oakes ex D. C. Eaton
Infrequent southeast; rare northeast, east central and south central

Asplenium rhizophyllum L.
Common east; absent northwest; rare elsewhere

Aster azureus Lindley
Frequent to common southeastern two-thirds

Aster brachyactis Blake
Rare north central and in lakes area

Aster cordifolius L.
Common southwest; frequent eastern half

Aster drummondii Lindley
Frequent southeast; infrequent to rare north and south central

Aster dumosus L.
Rare east and south central: Decatur County 1903, Delaware County, Johnson county, Louisa county and Marion county 1920

Aster ericoides L.
Frequent to common throughout

Aster falcatus Lindley ssp. commutatus (T. & G.) A. Gray
Rare northwest: Clay County 1936 and Palo Alto county 1936

Aster furcatus Burgess
Rare southeast and south central: Madison county 1917 and Muscatine county

Aster junciformis Rydb.
Rare north

Aster laevis L.
Frequent to common throughout

Aster lanceolatus Willd. [incl. ssp. simplex (Willd.) A. G. Jones; ssp. interior (Wiegand) A. G. Jones]
Rare to infrequent throughout

Aster lateriflorus (L.) Britton
Common southeast; frequent northeast; infrequent southwest

Aster linariifolius L.
Rare east central and southeast: Clinton County, Louisa county 1927 and Muscatine county 1896

Aster macrophyllus L.
Rare northeast: Winneshiek county

Aster novae-angliae L.
Frequent to common throughout

Aster oblongifolius Nutt.
Common southwest; frequent to infrequent elsewhere

Aster ontarionis Wieg.
Frequent to common throughout

Aster parviceps (Burgess) Mack. & Bush
Frequent to infrequent southwest; rare northeast

Aster pilosus Willd.
Rare northern half; common southern half

Aster praealtus Poiret
Frequent to infrequent eastern half of state

Aster praealtus Poiret var. nebraskensis (Britton) Wieg.
Rare northwest: Emmet county 1942

Aster prenanthoides Muhl. ex Willd.
Rare to infrequent eastern two-thirds of state

Aster pubentior Cronq.
Rare central: Jasper county

Aster puniceus L. [incl. var. lucidulus Gray]
Infrequent in Des Moines Lobe and in Iowan Surface; rare southeast and south central: Decatur County 1903 and Muscatine county 1927

Aster sagittifolius Willd.
Common southern half; frequent northeast; rare north central

Aster Schreberi Nees
Rare east central and southeast: Muscatine county and Scott county 1932

Aster sericeus Vent.
Common west; frequent to infrequent east

Aster shortii Lindley
Common northeast; infrequent southeast; rare north central

Aster turbinellus Lindley
Rare southeast: Lee county

Aster umbellatus Miller
Rare to infrequent throughout

Aster X amethystinus Nutt.
Rare north central and east central: Butler County, Floyd county and Scott county

Astragalus adsurgens Pallas var. robustior Hooker
Rare northwest: Dickinson county and Osceola county

Astragalus agrestis Douglas ex D. Don
Rare in northwest and north central

Astragalus canadensis L.
Common western half; infrequent to frequent eastern half

Astragalus crassicarpus Nutt.
Common northwest and north central; infrequent northeast, south central and southwest; rare or absent elsewh

Astragalus distortus T. & G.
Infrequent to rare east

Astragalus flexuosus (Hooker) G. Don
Rare northwest: Lyon county

Astragalus lotiflorus Hooker
Common northwest; rare north central and southwest

Astragalus missouriensis Nutt.
Rare west central and northwest: Plymouth county and Woodbury county

Athyrium filix-femina (L.) Roth var. angustum (Wilid.) Moore
Rare northwest; frequent to common elsewhere

Athyrium pycnocarpon (Sprengel) Tidestrom
Rare east

Athyrium thelypterioides (Michx.) Desv.
Infrequent to frequent east

Atriplex patula L. [incl. var. hastata (L.) Gray]
Infrequent to rare northwest, east and southern half

Atriplex rosea L.
Rare central, northwest and southwest: Cass County 1927, Emmet county 1932, Polk county 1911 and Sioux county 1931

Aureolaria grandiflora (Bentham) Pennell var. pulchra Pennell
Frequent extreme east; rare southeast and south central

Aureolaria pedicularia (L.) Raf.
Rare northeast: Allamakee County

Avena fatua L.
Rare throughout

Avena sativa L.
Infrequent escape from cultivation, not persisting

Azolla mexicana Presl
Common to infrequent along Mississippi River; rare east central and southwest: Benton County, Cedar County, Fremont county 1906, Johnson county and Linn county

Bacopa rotundifolia (Michx.) Wettst.
Infrequent southeast and south central; rare northwest and northeast

Ballota nigra L.
Rare southwest: Mills county

Baptisia australis (L.) R. Br. var. minor (Lehm.) Fern.
Rare northwest, south central and southwest: Adair County, Decatur County and Page county

Baptisia bracteata Muhl. ex Ell. var. glabrescens (Larisey) Isely
Infrequent to frequent throughout much of state; rare northwest and extreme east

Baptisia lactea (Raf.) Thieret
Infrequent to frequent throughout much of state; rare northwest and extreme northeast

Baptisia tinctoria (L.) R. Br. [incl. var. crebra Fern.]
Rare south central: Madison county 1917

Barbarea vulgaris R. Br. [incl. var. arcuata (Opiz) Fries]
Rare northwest; common elsewhere

Beckmannia syzigachne (Steudel) Fern.
Rare northwest: Clay County, Dickinson county, Emmet county, Lyon county, O'Brien county, Osceola county and Palo Alto county

Belamcanda chinensis (L.) DC.
Rare escape from cultivation

Berberis thunbergii DC.
Rare escape from cultivation

Berberis vulgaris L.
Rare escape from cultivation

Berteroa incana (L.) DC.
Rare northeast and south central; frequent to infrequent elsewhere

Berula erecta (Hudson) Cov. var. incisum (Torrey) Cronq.
Rare northwest and southwest: Cherokee County, Clay County, Dickinson county, Emmet county 1949, Palo Alto county 1936 and Pottawattamie county 1853

Besseya bullii (Eaton) Rydb.
Rare north and east

Betula alleghaniensis Britton
Rare central, north central and northeast: Allamakee County, Clayton County, Delaware County, Dubuque county, Fayette county, Hardin county, Mitchell county and Winneshiek county

Betula nigra L.
Common east; infrequent to frequent central; rare southwest

Betula papyrifera Marsh.
Common in Paleozoic Plateau; rare in Iowan Surface, and in central and east central: Hardin county, Johnson county

Betula pumila L. var. glandulifera Regel
Rare north central and northeast: Allamakee County, Black Hawk County, Bremer County, Chickasaw County, Clayton County, Howard county and Mitchell county

Betula pumila X Betula nigra
Rare northeast: Chickasaw County

Bidens aristosa (Michx.) Britton
Rare central, east central and southeast: Des Moines county, Iowa county 1928, Jefferson county, Keokuk county, Muscatine county, Poweshiek county, Scott county and Washington county

Bidens bipinnata L.
Rare southeast: Lee county and Louisa county

Bidens cernua L.
Frequent to common throughout

Bidens connata Muhl. ex Willd.
Common southeast; rare to frequent elsewhereere

Bidens coronata (L.) Britton
Common southwest; frequent to infrequent elsewhere

Bidens discoidea (T. & G.) Britton
Rare eastern quarter

Bidens frondosa L.
Common north central and in lakes area; rare to infrequent elsewhere

Bidens polylepis Blake
Common southwest; rare northeast; infrequent elsewhere

Bidens tripartita L.
Common southeast; rare to infrequent elsewhere

Bidens vulgata Greene
Rare northwest and northeast; frequent to common elsewhere

Blephilia ciliata (L.) Bentham
Rare southeast and south central: Appanoose County 1902, Davis County 1939, Des Moines county, Henry county n.d., Jefferson county 1934, Lee county and Van Buren county

Blephilia hirsuta (Pursh) Bentham
Not reported from northwest; rare north central and in Iowan Surface; infrequent elsewhere

Boehmeria cylindrica (L.) SW.
Frequent to common south central and extreme east; infrequent to rare elsewhere

Boltonia asteroides (L.) L'Her. [incl. var. recognita (Fern. & Grisc.) Cronq.; var. latisquama (Gray) Cronq.]
Common north central; infrequent to frequent south, also Dickinson county

Botrychium campestre Wagner & Farrar
Rare west; discovered in 1982

Botrychium dissection Sprengel f. dissectum
Rare eastern half

Botrychium dissectum Sprengel f. obliquum (Muhl.) Fern.
Infrequent eastern half

Botrychium matricariifolium A. Br.
Rare northeast: Allamakee County

Botrychium multifidum (Gmelin) Rupr.
Rare northeast: Allamakee County, Buchanan County, Clayton County, Dubuque county, Fayette county 1893, Linn county and Winneshiek county

Botrychium simplex E. Hitchc.
Rare central, northeast and east central: Black Hawk County, Linn county and Marshall county

Botrychium virginianum (L.) SW.
Common east; frequent west

Bouteloua curtipendula (Michx.) Torrey
Frequent to common throughout

Bouteloua gracilis (Willd. ex HBK.) Lag. ex Steudel
Frequent west

Bouteloua hirsuta Lag.
Frequent to infrequent west; rare elsewhere

Brachyelytrum erectum (Schreber) Beauv.
Frequent to common east; rare elsewhere

Brasenia schreberi J. F. Gmelin
Rare in scattered localities throughout

Brassica campestris L.
Rare escape from cultivation

Brassica juncea (L.) Czern.
Common southwest; infrequent elsewhere

Brassica Kaber (DC.) Wheeler
Rare southwest: Page county

Brassica napus L.
Rare escape from cultivation

Brassica nigra (L.) W. D. J. Koch
Absent northwest; frequent to common elsewhere

Brassica oleracea L.
Rare escape from cultivation

Brickellia eupatorioides (L.) Shinners [incl. var. corymbulosa (T. & G.) Shinners]
Frequent to common throughout

Bromus ciliatus L.
Rare in northeastern quarter

Bromus commutatus Schrader
Infrequent throughout much of state

Bromus inermis Leysser
Common throughout

Bromus japonicus Thunb. ex Murray
Frequent to common throughout

Bromus kalmii Gray
Frequent in Paleozoic Plateau; rare elsewhere in east

Bromus latiglumis (Shear) A. S. Hitchc.
Infrequent to frequent east; rare southwest

Bromus mollis L.
Rare central and northeast: Black Hawk County 1896 and Webster county n.d.

Bromus pubescens Muhl. ex Willd.
Frequent to infrequent throughout

Bromus secalinus L.
Infrequent southeast and southwest; rare elsewhere

Bromus tectorum L.
Frequent to common throughout

Buchloe dactyloides (Nutt.) Engelm.
Rare, native in west central and northwest: Lyon county, Plymouth county and Woodbury county, introduced elsewh

Bulbostylis capillaris (L.) C. B. Clarke
Rare to infrequent east

Cacalia atriplicifolia L.
Infrequent to frequent southern half

Cacalia muhlenbergii (Sch.-Bip.) Fern.
Rare northeast (except frequent in Paleozoic Plateau), and in southeast and southwest: Muscatine county and Cass County

Cacalia plantaginea (Raf.) Shinners
Common southwest; infrequent elsewhere

Cacalia suaveolens L.
Rare eastern half and southwest

Calamagrostis canadensis (Michx.) Beauv.
Infrequent to rare in westernmost counties; frequent to common elsewhere

Calamagrostis inexpansa Gray
Frequent in lakes area; rare remainder of north

Calamovilfa longifolia (Hooker) Scribner
Infrequent to rare throughout

Calamovilfa longifolia (Hooker) Scribner var. magna Scribner & Merr.
Rare southeast: Louisa county and Muscatine county

Callirhoe alcaeoides (Michx.) Gray
Rare northwest and southwest: Dickinson county, Page county

Callirhoe bushii Fern.
Rare southwest: Page county

Callirhoe involucrata (Nutt. ex T. & G.) Gray
Rare northwest and southern half

Callirhoe triangulata (Leavenw.) Gray
Rare east: Allamakee County, Clinton County and Davis County (early 1900's)

Callitriche heterophylla Pursh
Rare: scattered throughout

Callitriche verna L.
Rare in lakes area and in Paleozoic Plateau

Calopogon tuberosus (L.) BSP.
Rare east (all pre-1900 except Linn county 1951)

Caltha palustris L.
Frequent north central and northeastern quarter; rare northwest, southeast and southwest

Calylophus serrulatus (Nutt.) Raven
Common northwest and north central; frequent to infrequent rest of northwestern half

Calystegia sepium (L.) R. Br. [incl. var. americana (Sims) Matsuda; var. fraterniflora (Mack. & Bush) Shinners]
Common throughout

Calystegia spithamaea (L.) Pursh
Rare east

Camassia scilloides (Raf.) Cory
Infrequent to rare southern half

Camelina microcarpa Andrz. ex DC.
Infrequent to rare throughout

Camelina sativa (L.) Crantz
Rare north central, northeast and southwest

Campanula americana L.
Common throughout

Campanula aparinoides Pursh
Frequent north central; rare to absent elsewhere

Campanula rapunculoides L.
Rare escape from cultivation

Campanula rotundifolia L.
Common extreme east and in Paleozoic Plateau; rare central

Campsis radicans (L.) Seem, ex Bureau
Infrequent escape from cultivation

Cannabis sativa L.
Common throughout

Capsella bursa-pastoris (L.) Medicus
Common throughout

Caragana arborescens Lam.
Rare northeast: Dubuque county

Cardamine bulbosa (Schreber) BSP.
Common northeast; rare west; infrequent elsewhere

Cardamine douglassii (Torrey) Britton
Rare southeastern quarter

Cardamine parviflora L. var. arenicola (Britton) Schulz
Rare in Iowan Surface

Cardamine pensylvanica Muhl. ex Willd.
Frequent to infrequent northeastern two-thirds; rare south central: Decatur County

Cardaria chalapensis (L.) Handel-Mazzetti
Rare southwest: Page county

Cardaria draba (L.) Desv.
Infrequent north central and southwest; rare northwest and south central

Carduus acanthoides L.
Rare southern half; infrequent northwest

Carduus nutans L.
Frequent to common western half; rare eastern half

Carex aggregata Mack.
Rare central, northeast and southwest: Allamakee County, Clayton County, Page county and Story county

Carex albursina Sheldon
Frequent to common east; rare to infrequent elsewhere

Carex alopecoidea Tuckerman
Rare in lakes area, southeast and south central

Carex amphibola Steudel var. turgida Fern.
Infrequent northern half; infrequent to common southern half

Carex annectens (Bickn.) Bickn. var. xanthocarpa (Bickn.) Wieg.
Rare to infrequent southwest three-quarters

Carex aquatilis Wahl.
Rare northwest and central

Carex artitecta Mack.
Rare southwest, southeast and in lakes area

Carex assiniboinensis W. Boott
Rare north

Carex atherodes Sprengel
Frequent to common central and in lakes area; rare to infrequent elsewhere

Carex backii F. Boott
Rare northwest and northeast: Allamakee County, Dubuque county, Emmet county and Winneshiek county

Carex bebbii (Bailey) Fern.
Infrequent northern half; rare southern half

Carex bicknellii Britton
Frequent west three-quarters; rare e

Carex blanda Dewey
Common throughout

Carex brevior (Dewey) Mack. ex Lunell
Common west and southeast; frequent elsewh

Carex bushii Mack.
Rare southeast and southwest: Davis County 1939, Lee county, Page county and Wapello county 1939

Carex buxbaumii Wahl.
Rare to infrequent e three-quarters

Carex careyana Dewey
Rare northeast and east central

Carex cephalantha (Bailey) Bickn.
Rare north central: Hancock county

Carex cephaloidea (Dewey) Dewey
Rare to infrequent e three-quarters

Carex cephalophora Willd.
Frequent to common southeast three-quarters

Carex chordorrhiza Ehrh. ex L. f.
Rare northwest and north central: Emmet county 1884 and Hancock county

Carex communis Bailey
Rare southern half; infrequent in Paleozoic Plateau

Carex comosa Boott
Frequent in lakes area; rare elsewhere

Carex conjuncta Boott
Rare to infrequent throughout

Carex conoidea Schkuhr ex Willd.
Rare northeast and east central

Carex convoluta Mack.
Common northern half

Carex crawei Dewey
Rare northwest, north central and east central: Emmet county 1904, Floyd county and Johnson county

Carex crawfordii Fern.
Rare west central and northwest

Carex crinita Lam.
Rare east central and southeast: Jefferson county 1934 and Linn county

Carex cristatella Britton
Rare northwest and east; common southwest; infrequent to frequent elsewh

Carex crus-corvi Shuttlew. ex Kunze
Rare northwest; infrequent southern half

Carex davisii Schwein. & Torrey
Rare northern half; frequent southern half

Carex deweyana Schwein.
Infrequent in Paleozoic Plateau; rare in lakes area and c

Carex diandra Schrank
Rare central, northwest, north central and east central: Cerro Gordo County 1917, Dickinson county, Emmet county 1925, Johnson county 1941, Webster county 1909 and Winnebago county 1899

Carex douglasii Boott
Rare central: Jasper county 1904

Carex eburnea Boott
Rare to infrequent northern half and southwest; frequent e

Carex eleocharis Bailey
Frequent northwest, especially in lakes area

Carex emoryi Dewey
Rare southwest, in lakes area and in Paleozoic Plateau

Carex festucacea Schkuhr ex Willd.
Rare northwest and southeast: Dickinson county and Louisa county

Carex foenea Willd.
Rare northwest: Clay County 1936

Carex frankii Kunth
Rare southeast, south central and extreme e

Carex gracilescens Steudel
Rare southeast: Des Moines county and Wapello county 1938

Carex gracillima Schwein.
Rare north except frequent in Paleozoic Plateau

Carex granularis Muhl. ex Willd.
Rare north central; infrequent eastern half

Carex gravida Bailey
Frequent to common throughout

Carex grayi Carey
Infrequent southeastern two-thirds

Carex haydenii Dewey
Rare to infrequent northern half; rare southern half

Carex heliophila Mack.
Infrequent throughout

Carex hirsutella Mack.
Frequent southeast; rare south central; not reported elsewh

Carex hirtifolia Mack.
Common in Paleozoic Plateau; infrequent to rare northeast three-quarters

Carex hitchcockiana Dewey
Frequent in lakes area; rare to infrequent elsewhere

Carex hyalinolepis Steudel
Rare southwest: Fremont county

Carex hystericina Muhl. ex Willd.
Common north central; infrequent to frequent elsewh

Carex interior Bailey
Rare to infrequent eastern two-thirds

Carex jamesii Schwein.
Rare to infrequent e three-quarters

Carex lacustris Willd.
Frequent north central; rare northwest and southeast

Carex laeviconica Dewey
Rare in much of state; not reported from southeast

Carex laevivaginata (Kuek.) Mack.
Rare to infrequent throughout

Carex lanuginosa Michx.
Common in lakes area; rare extreme east; infrequent to frequent elsewh

Carex lasiocarpa Ehrh. var. americana Fern.
Rare central, northwest, east central and southeast

Carex laxiculmis Schwein.
Rare southeastern quarter

Carex leavenworthii Dewey
Frequent to infrequent southeast; rare northeast

Carex leptalea Wahl.
Rare northeast and east central: Benton County, Black Hawk County and Buchanan County

Carex limosa L.
Rare northwest and north central: Emmet county 1892 and Hancock county

Carex lupuliformis Sartw. ex Dewey
Rare southeast and south central: Decatur County 1900 and Lee county 1931

Carex lupulina Muhl. ex Willd.
Infrequent to frequent east; rare northwest

Carex lurida Wahl.
Rare central, southeast and south central: Jefferson county 1945, Lee county 1931, Mahaska county and Story county 1886

Carex meadii Dewey
Rare northwest and northeast; frequent to infrequent elsewhere

Carex media R. Br.
Rare northeast: Clayton County and Delaware County; disjunorth centralt from north Wise.

Carex molesta Mack.
Frequent north, south central and southwest; rare to infrequent elsewhere

Carex muhlenbergii Schkuhr ex Willd. [incl. var. enervis Boott]
Frequent southeast; rare to infrequent elsewhere

Carex muskingumensis Schwein.
Rare north; infrequent s

Carex normalis Mack.
Frequent northeast; infrequent elsewhere

Carex oligocarpa Willd.
Frequent in Paleozoic Plateau; rare to infrequent elsewhere

Carex peckii Howe
Frequent in Paleozoic Plateau

Carex pedunculata Muhl. ex Willd.
Common in Paleozoic Plateau; rare to infrequent in remainder of northeastern half

Carex pensylvanica Lam.
Common throughout

Carex plantaginea Lam.
Rare e

Carex praegracilis W. Boott
Infrequent to rare west three-quarters

Carex prairea Dewey
Frequent in lakes area; rare e

Carex projecta Mack.
Rare eastern half and north central

Carex retroflexa Muhl. ex Willd.
Rare east central: Jones county

Carex retrorsa Schwein.
Infrequent north central; rare northeast

Carex richardsonii R. Br.
Rare central and n

Carex rosea Schkuhr ex Willd.
Frequent to common northwest and south; rare in lakes area

Carex rostrata Stokes ex Willd. var. utriculata (Boott) Bailey
Rare in scattered sites throughout

Carex sartwellii Dewey
Infrequent throughout

Carex saximontana Mack.
Rare west central and northwest: Lyon county, Plymouth county and Woodbury county

Carex scoparia Schkuhr ex Willd.
Common northeastern quarter, except rare in Paleozoic Plateau; infrequent to frequent elsewh

Carex shortiana Dewey
Frequent to infrequent southeast and south central; rare northeast

Carex sparganioides Muhl. ex Willd.
Infrequent to frequent throughout

Carex sprengelii Dewey ex Sprengel
Common in Paleozoic Plateau; rare southeast; frequent to infrequent elsewhere

Carex squarrosa L.
Rare southeast

Carex sterilis Willd.
Rare northeast: Buchanan County, Chickasaw County, Fayette county and Winneshiek county

Carex stipata Muhl. ex Willd.
Frequent north central and northeast; rare south central and southwest

Carex stricta Lam.
Common southwest; rare southeast and extreme east; infrequent to frequent elsewh

Carex suberecta (Olney) Britton
Infrequent north central; rare northeast, southeast and southwest

Carex sychnocephala Carey
Infrequent northwest, especially in lakes area; rare southeast: Louisa county

Carex tenera Dewey
Not reported east central and southeast; rare elsewhere

Carex tetanica Schkuhr
Rare to infrequent northern half

Carex tonsa (Fern.) Bickn.
Rare east

Carex tribuloides Wahl.
Common southern half; infrequent extreme east; rare northwest

Carex trichocarpa Schkuhr
Rare throughout most of state

Carex tuckermanii Dewey
Rare central: Jasper county 1897

Carex typhina Michx.
Rare southeastern two-thirds

Carex umbellata Schkuhr ex Willd.
Rare northeast: Allamakee County and Dubuque county

Carex vesicaria L.
Infrequent north central and northeast; rare southern half

Carex vulpinoidea Michx.
Common throughout

Carex woodii Dewey
Infrequent to rare northeast

Carpinus caroliniana Walter
Common northeast; infrequent north central and southeast

Carya cordiformis (Wang.) K. Koch
Infrequent northwest and north central; common elsewhere

Carya illinoensis (Wang.) K. Koch
Rare southeastern quarter, northeast (Dubuque county); introduced in north central (Kossuth county)

Carya laciniosa (Michx. f.) Loudon
Rare southeastern quarter

Carya ovata (P. Miller) K. Koch
Rare northwest; common elsewhere

Carya tomentosa (Poiret) Nutt.
Infrequent southeast; rare elsewhere in south

Cassia marilandica L.
Infrequent southern half; rare northeast and east central

Castanea dentata (Marsh.) Borkh.
Rare: scattered trees persisting from cultivation

Castilleja coccinea (L.) Sprengel
Infrequent to rare north central, and in northwest: Sioux county

Castilleja sessiliflora Pursh
Infrequent northern half and southwest

Catalpa bignonioides Walter
Rare escape from cultivation

Catalpa speciosa Warder
Infrequent throughout

Caulophyllum thalictroides (L.) Michx.
Common north central and northeast; infrequent northwest and southeast; rare southwest

Ceanothus americanus L. var. pitcheri T. & G.
Frequent northwest; infrequent south central; common elsewhere

Ceanothus herbaceus Raf. var. pubescens (T. & G.) Shinners
Common northwest and extreme northeast; frequent southwest; infrequent central

Celastrus orbiculatus Thunb.
Rare escape in northeast and south central: Delaware County and Mahaska county

Celastrus scandens L.
Infrequent northwest; common elsewhere

Celtis occidentalis L. [incl. var. pumila (Pursh) Gray; var. canina (Raf.) Sarg.]
Common throughout

Cenchrus longispinus (Hackel) Fern.
Frequent to common throughout

Centaurea calcitrapa L.
Rare central: Story county

Centaurea cyanus L.
Rare escape from cultivation

Centaurea diffusa Lam.
Rare northwest: Sioux county

Centaurea jacea L.
Rare northwest: Cherokee County 1924

Centaurea maculosa Lam.
Infrequent to rare throughout

Centaurea moschata L.
Rare central: Polk county 1928

Centaurea nigra L.
Rare west central: Calhoun County 1911

Centaurea repens L.
Rare west central and northwest: Sioux county 1933, Woodbury county

Centaurea scabiosa L.
Rare west central and northwest: O'Brien county 1944, Sac county

Centaurea solstitialis L.
Rare south central and southwest

Cephalanthus occidentalis L.
Common southern half and east; infrequent to rare elsewhere

Cerastium arvense L.
Rare northeast and east central: Allamakee County, Clayton County, Delaware County, Dubuque county, Fayette county, Jackson county, Howard county and Winneshiek county

Cerastium glomeratum Thuill.
Rare northwest and east: Buchanan County, Cedar County, Jones county, Linn county 1896, Lyon county, Muscatine county and Scott county 1895

Cerastium nutans Raf.[incl. var. brachypodum Engelm. ex Gray]
Common southwest; frequent east; infrequent north central and south central

Cerastium vulgatum L.
Frequent eastern half; infrequent north central

Ceratophyllum demersum L.
Frequent south and in lakes area; rare to infrequent north

Cercis canadensis L.
Common southeast; infrequent south central and southwest; adventive northeast

Chaenorrhinum minus (L.) Lange
Frequent to infrequent southern half; rare northern half

Chaerophyllum procumbens (L.) Crantz
Frequent north central and southeast; rare northeast and extreme east

Chamaecrista fasciculata (Michx.) Greene
Frequent to common throughout

Chasmanthium latifolium (Michx.) H. Yates
Rare southeast: Lee county

Cheilanthes feei Moore
Infrequent northeast

Chelidonium majus L.
Rare escape from cultivation: Allamakee County, Black Hawk County, Cherokee County, Iowa county, Johnson county and Winneshiek county

Chelone glabra L.
Rare throughout most of state; not reported from extreme w

Chelone obliqua L. var. speciosa Pennell & Wherry
Rare north central, east central and southeast: Clinton County 1930, Des Moines county, Lee county 1898, Mitchell county 1929, Muscatine county 1894 and Scott county

Chenopodium album L. [incl. var. lanceolatum (Muhl.) Cosson & Germ.]
Frequent in Paleozoic Plateau; common elsewhere

Chenopodium ambrosioides L.
Rare southern half and north central

Chenopodium berlandieri Moq. [incl. var. zschackei (Murr) Murr]
Common north central; rare east central and southeast: Johnson county and Henry county

Chenopodium botrys L.
Infrequent central; rare northeast and southeast

Chenopodium bushianum Aellen
Common north central; rare extreme east

Chenopodium capitatum (L.) Ascherson
Rare northeast and east central: Allamakee County 1939 and Johnson county 1907

Chenopodium desiccatum A. Nelson
Frequent southern half; infrequent northwest and northeast; rare north central

Chenopodium foggii H. A. Wahl
Rare central, east central and southeast: Des Moines county, Iowa county 1928 and Story county 1907

Chenopodium glaucum L.
Rare west central, north central, east central, southeast, and southwest

Chenopodium hybridum L. [incl. var. gigantospermum (Aellen) Rouleau]
Frequent southwest; infrequent northeast; rare northwest: Dickinson county

Chenopodium missouriensis Aellen
Rare central and southeast: Lee county, Louisa county, Story county and Tama county

Chenopodium murale L.
Rare northwest, north central and southeast

Chenopodium polyspermum L.
Rare weed in northwest and east central: Emmet county and Johnson county 1902

Chenopodium rubrum L.
Rare northwest: Clay County 1936, Dickinson county, Emmet county 1922 and Palo Alto county 1935

Chenopodium standleyanum Aellen
Frequent north central, southeast and south central; infrequent northwest and northeast

Chenopodium strictum Roth var. glaucophyllum (Aellen) H. A. Wahl
Common north central

Chenopodium urbicum L.
Rare weed throughout

Chimaphila umbellata (L.) Bartram
Rare northeast and east central: Allamakee County, Fayette county 1895, Jackson county 1896, Linn county 1911 and Winneshiek county

Chloris verticillata Nutt.
Rare escape from plantings in central and southeast

Chorispora tenella (Pallas) DC.
Rare central, west central, northwest and northeast: Clay County, Dubuque county, Plymouth county, Sac county, Story county and Woodbury county 1930

Chrysosplenium iowense Rydb.
Rare northeast and east central: Allamakee County, Clayton County, Dubuque county, Fayette county, Howard county, Jackson county and Winneshiek county

Cichorium intybus L.
Rare northeast; common elsewhere

Cicuta bulbifera L.
Frequent in lakes area; rare eastern half

Cicuta maculata L.
Frequent to common throughout most of state; rare west

Cimicifuga racemosa (L.) Nutt.
Rare west central: Woodbury county 1938

Cinna arundinacea L.
Frequent to infrequent throughout most of state

Circaea alpina L.
Frequent in Paleozoic Plateau; rare southeast: Muscatine county 1896

Circaea lutetiana L. ssp. canadensis (L.) Ascherson & Magnus
Frequent to common throughout

Cirsium altissimum (L.) Sprengel
Rare northeast; infrequent northwest; common elsewhere

Cirsium arvense (L.) Scop.
Frequent to common throughout

Cirsium discolor (Muhl. ex Willd.) Sprengel
Frequent to common throughout

Cirsium flodmanii (Rydb.) Arthur
Common northwest; frequent west; rare northeast

Cirsium hillii (Canby) Fern.
Not reported west and south; rare to infrequent elsewhere

Cirsium muticum Michx.
Rare northeastern two-thirds

Cirsium undulatum (Nutt.) Sprengel
Rare central, northwest, east central, southeast and southwest

Cirsium vulgare (Savi) Tenore
Frequent to common throughout

Claytonia virginica L.
Frequent to common throughout

Clematis occidentalis (Hornem.) DC.
Rare northeast: Allamakee County, Clayton County, Dubuque county and Winneshiek county

Clematis pitcheri T. & G.
Common southeast; frequent south central; infrequent to rare elsewhere

Clematis virginiana L.
Frequent to common northern half; infrequent southern half

Cleome serrulata Pursh
Rare, persisting only in northwest

Coeloglossum viride (L.) Hartman var. virescens (Muhl. ex Willd.) Luer
Infrequent northeast three-quarters

Collinsia verna Nutt.
Rare southeast: Jefferson county 1896 and Washington county

Collomia linearis Nutt.
Rare: adventive in north, east central and south central

Comandra umbellata (L.) Nutt.
Common throughout

Commelina communis L.
Absent northwest and extreme northeast; infrequent to frequent elsewh

Commelina erecta L. var. angustifolia (Michx.) Fern.
Rare southeast: Lee county 1931, Louisa county and Muscatine county

Conium maculatum L.
Infrequent southern half; rare northern half; not reported from Paleozoic Plateau

Conopholis americana (L.) Wallr.
Rare northeast: Allamakee County

Conringia orientalis (L.) Dum.
Infrequent to rare throughout

Consolida ambigua (L.) Ball & Heywood
Rare escape from cultivation south

Convallaria majalis L.
Rare escape from cultivation

Convolvulus arvensis L.
Rare southeast; frequent to common elsewhere

Conyza canadensis (L.) Cronq.
Common throughout

Conyza ramosissima Cronq.
Rare to infrequent throughout

Corallorhiza maculata (Raf.) Raf.
Rare northeast: Allamakee County, Clayton County, Dubuque county and Winneshiek county

Corallorhiza odontorhiza (Willd.) Nutt.
Rare and local throughout

Coreopsis grandiflora Hogg ex SWeet
Rare escape from cultivation

Coreopsis lanceolata L.
Rare southeast

Coreopsis palmata Nutt.
Infrequent southeast; frequent to common elsewhere

Coreopsis tinctoria Nutt.
Rare escape from cultivation, also adventive from west

Coreopsis tripteris L.
Infrequent southern half

Corispermum nitidum Kit. ex Schultes
Rare west central: Harrison county 1952

Cornus alternifolia L. f.
Frequent to common northeastern two-thirds; rare south; absent northwest and southwest

Cornus amomum P. Miller ssp. obliqua (Raf.) J. S. Wilson
Common in northeastern quarter; infrequent throughout most of state

Cornus canadensis L.
Rare northeast: Allamakee County, Clayton County, Delaware County and Winneshiek county

Cornus drummondii C. A. Meyer
Frequent to common throughout most of state; rare in Paleozoic Plateau and extreme north

Cornus foemina P. Miller ssp. racemosa (Lam.) J. S. Wilson
Common throughout most of state; rare northwest

Cornus rugosa Lam.
Common in Paleozoic Plateau; infrequent to rare elsewhere

Cornus stolonifera Michx.
Rare in northern tier of counties; absent or rare escape from cultivation elsewh

Coronilla varia L.
Common, planted along highways throughout

Corydalis aurea Willd.
Rare in scattered localities throughout

Corydalis curvisiliqua Engelm. ssp. grandibracteata (Fedde) G. Ownbey
Rare southeast and south central: Henry county, Lee county, Louisa county, Mahaska county and Muscatine county

Corydalis micrantha (Engelm.) Gray
Frequent southeast and south central; infrequent southwest; infrequent to rare north central and northeast

Corydalis sempervirens (L.) Pers.
Rare northeast: Allamakee County

Corylus americana Walter
Infrequent northwest; common elsewhere

Corylus cornuta Marsh.
Frequent in Paleozoic Plateau; infrequent rest of northeastern quarter

Crataegus calpodendron (Ehrh.) Medicus
Infrequent to rare throughout

Crataegus chrysocarpa Ashe
Rare north; all records before 1950

Crataegus coccinea L.
Rare central and east: Dubuque county, Hardin county, Lee county, Linn county and Wapello county

Crataegus crus-galli L.
Infrequent southwest and extreme east; frequent remainder of southern half

Crataegus disperma Ashe
Rare south central and southeast: Davis County 1940, Decatur County 1940 and Wapello county 1940

Crataegus margaretta Ashe
Infrequent to frequent eastern half

Crataegus mollis (T. & G.) Scheele
Infrequent in Paleozoic Plateau; frequent to common elsewhere

Crataegus pruinosa (Wendl. f.) K. Koch
Rare central and southeast: Boone County 1940 and Wapello county 1929

Crataegus punctata Jacq.
Rare northwest and southeast; frequent to infrequent elsewhere

Crataegus succulenta Schrader ex Link
Infrequent northwest; rare throughout much of state

Crepis runcinata (James) T. & G.
Rare northwest and northeast: Black Hawk County 1921 and Osceola county 1912

Crepis tectorum L.
Rare escape from cultivation in west central and central

Crotalaria sagittalis L.
Infrequent to frequent northern half; rare southern half

Croton capitatus Michx.
Infrequent to rare south; loess bluffs in northwest and southwest

Croton glandulosus L. var. septentrionalis Mueller-Arg.
Frequent southeastern quarter; rare northeast: Clayton County

Croton monanthogynus Michx.
Rare central, west central and southeast: Davis County, Lee county 1917, Monona county, Van Buren county 1954 and Wapello county 1940

Croton texensis (Kl.) Mueller-Arg. ex DC.
Rare southeast: Muscatine county 1897

Crotonopsis elliptica Willd.
Rare southwest: Ringgold county

Cryptogramma stelleri (Gmelin) Prantl
Rare north central; infrequent northeast

Cryptotaenia canadensis (L.) DC.
Common throughout

Cucurbita foetidissima HBK.
Rare southern half

Cuphea viscosissima Jacq.
Rare southeast: Davis County, Jefferson county 1935 and Lee county 1917

Cuscuta cephalanthii Engelm.
Infrequent to rare throughout, except not reported southwest

Cuscuta coryli Engelm.
Infrequent central and north central

Cuscuta cuspidata Engelm.
Infrequent to rare throughout

Cuscuta glomerata Choisy
Common north central; infrequent southeast; infrequent to rare western half

Cuscuta gronovii Willd.
Infrequent to rare eastern two-thirds; rare northwest: Dickinson county, Emmet county and Lyon county

Cuscuta indecora Choisy
Rare west and east central: Clinton County, Harrison county, Linn county, Lyon county and Pottawattamie county

Cuscuta pentagona Engelm.
Infrequent north central; rare in central, northwest, southeast and south central: Boone County, Dallas County 1919, Lee county 1925, Lyon county 1896 and Mahaska county

Cuscuta polygonorum Engelm.
Infrequent southeast; rare elsewhere

Cycloloma atriplicifolium (Sprengel) Coulter
Frequent to common southeast; infrequent extreme east and south central; rare elsewhere

Cynanchum laeve (Michx.) Pers.
Frequent southwest; rare southeast: Lee county and Louisa county in late 1800's

Cynoglossum officinale L.
Frequent in Paleozoic Plateau; infrequent to rare elsewhere

Cyperus acuminatus Torrey & Hooker
Infrequent to rare southwestern two-thirds

Cyperus aristatus Rottb.
Frequent north central; infrequent southwestern half; rare east

Cyperus diandrus Torrey
Rare throughout most of state

Cyperus engelmannii Steudel
Rare northern half

Cyperus erythrorhizos Muhl.
Frequent south; infrequent to rare northern half and east

Cyperus esculentus L.
Frequent to common southern half and north central; infrequent to rare elsewhere

Cyperus filiculmis Vahl
Common locally in extreme northeast; frequent southern half; rare elsewhere

Cyperus odoratus L. var. squarrosus (Britton) Gilly
Frequent to common northwest; infrequent southern half; infrequent to rare northeastern quarter

Cyperus rivularis Kunth
Frequent to infrequent throughout

Cyperus Schweinitzii Torrey
Frequent to infrequent northeastern half

Cyperus strigosus L.
Frequent to common throughout

Cypripedium calceolus L. var. parviflorum (Salisb.) Fern.
Rare northeast: Buchanan County and Chickasaw County

Cypripedium calceolus L. var. pubescens (Willd.) Correll
Infrequent to rare eastern half; rare and scattered western half

Cypripedium candidum Muhl. ex Willd.
Rare and local throughout

Cypripedium reginae Walter
Rare and local northeast; formerly scattered eastern two-thirds

Cypripedium X andrewsii Fuller
Rare northeast and south central: Bremer County, Chickasaw County, Decatur County, Fayette county and Howard county

Cystopteris bulbifera (L.) Bernh.
Rare central; frequent to common east

Cystopteris fragilis (L.) Bernh.
Rare in Paleozoic Plateau, central and northwest

Cystopteris protrusa (Weath.) Blasdell
Common south; frequent north central; rare northwest and northeast

Cystopteris tenuis (Michx.) Desv.
Frequent northeast; absent west; infrequent elsewhere

Cystopteris X laurentiana (Weath.) Blasdell
Rare northeast: Allamakee County n.d., Howard county and Winneshiek county

Cystopteris X tennesseensis Shaver
Rare eastern half

Dactylis glomerata L.
Common escape from cultivation throughout

Dalea candida Willd.
Common western half; frequent eastern half; absent from Loess Hills

Dalea candida Willd. var. oligophylla (Torrey) Shinners
Infrequent northwest; rare southwest

Dalea enneandra Nutt.
Common southwest; infrequent northwest

Dalea leporina (Aiton) Bullock
Infrequent southern half; rare northwest and east; frequent on Missouri R. floodplain

Dalea purpurea Vent.
Frequent to common throughout

Dalea villosa (Nutt.) Sprengel
Rare northeast: Black Hawk County

Danthonia spicata (L.) Beauv. ex R. & S.
Infrequent to rare throughout

Dasistoma macrophylla (Nutt.) Raf.
Infrequent southeast and south central

Datura stramonium L. [incl. var. tatula (L.) Torrey]
Frequent southern half; infrequent to rare northern half

Daucus carota L.
Frequent to common throughout

Decodon verticillatus (L.) Ell.
Rare northeast and east central: Allamakee County and Scott county 1890

Delphinium carolinianum Walter
Rare central, southeast and south central: Lee county, Mahaska county and Poweshiek county

Delphinium tricorne Michx.
Infrequent to rare southern half

Delphinium virescens Nutt. [incl. var. penardii (Huth.) Perry]
Infrequent south central; rare southeast; frequent to common elsewhere

Dentaria laciniata Muhl. ex Willd.
Not reported from northwest; frequent to common elsewhere

Descurainia pinnata (Walter) Britton var. brachycarpa (Richardson) Fern.
Rare southwest; frequent to common elsewhere

Descurainia sophia (L.) Webb ex Prantl
Frequent northwest; rare southwest, and in southeast: Muscatine county 1890

Desmanthus illinoensis (Michx.) MacM. ex B. L. Robinson & Fern.
Common southwest in loess; infrequent to rare elsewhere

Desmodium canadense (L.) DC.
Common northwest, northeast and south; infrequent to frequent elsewh

Desmodium canescens (L.) DC.
Infrequent to rare throughout

Desmodium cuspidatum (Muhl. ex Willd.) Loudon [incl. var. longifolium (T. & G.) Schub.]
Common northeast; infrequent to rare elsewhere

Desmodium glutinosum (Muhl. ex Willd.) Wood
Frequent to common throughout most of state; rare northwest

Desmodium illinoense Gray
Frequent to common southern half and east; rare elsewhere

Desmodium nudiflorum (L.) DC.
Infrequent in Paleozoic Plateau; rare remainder of eastern half

Desmodium paniculatum (L.) DC.
Common southeast; infrequent to rare south central and southwest; rare northern half

Desmodium sessilifolium (Torrey) T. & G.
Rare central, northeast and southeast: Black Hawk County 1895, Des Moines county, Lee county and Poweshiek county

Dianthus armeria L.
Infrequent to rare southern half

Diarrhena americana Beauv. var. obovata Gl.
Infrequent to rare south three-quarters

Dicentra canadensis (Goldie) Walp.
Frequent northeastern quarter; absent west; infrequent elsewhere

Dicentra cucullaria (L.) Bernh.
Frequent northwest; common elsewhere

Dichanthelium acuminatum (SW.) Gould & Clark
Rare eastern quater; frequent to common elsewhere

Dichanthelium acuminatum (SW.) Gould & Clark var. implicatum (Scribner) Gould & Clark
Rare west; frequent to common elsewhere

Dichanthelium acuminatum (SW.) Gould & Clark var. lindheimeri (Nash) Gould & Clark
Rare east: Bremer County, Clinton County, Jones county, Louisa county and Scott county

Dichanthelium acuminatum (SW.) Gould & Clark var. villosum (Gray) Gould & Clark
Infrequent northeastern half

Dichanthelium boreale (Nash) Freckm.
Rare northeast: Black Hawk County, Buchanan County and Clayton County 1923

Dichanthelium clandestinum (L.) Gould
Infrequent to rare southeast

Dichanthelium depauperatum (Muhl.) Gould
Rare central, north central and extreme east

Dichanthelium latifolium (L.) Gould & Clark
Frequent to infrequent eastern two-thirds

Dichanthelium leibergii (Vasey) Freckm.
Common north central; rare northwest and southeast; infrequent elsewhere

Dichanthelium linearifolium (Scribner) Gould
Rare west central, southeast and south central: Guthrie county, Marion county and Wapello county

Dichanthelium oligosanthes (Schultes) Gould
Rare throughout

Dichanthelium oligosanthes (Schultes) Gould var. Scribnerianum (Nash) Gould
Frequent to common throughout

Dichanthelium oligosanthes (Schultes) Gould var. wilcoxianum (Vasey) Gould & Clark
Frequent northwest; rare elsewhere

Dichanthelium perlongum (Nash) Freckm.
Rare, eastern two-thirds

Dichanthelium sabulorum (Lam.) Gould & Clark var. patulum (Scribner & Merr.) Gould & Clark
Infrequent to rare eastern half

Dichanthelium sabulorum (Lam.) Gould & Clark var. thinium (A. S. Hitchc. & Chase) Gould & Clark
Rare northeast: Allamakee County

Didiplis diandra (DC.) Wood
Rare eastern half

Diervilla lonicera Miller
Common in Paleozoic Plateau; rare rest of northeast and southeast

Digitaria ciliaris (Retz.) Koeler
Rare southwest: Fremont county, Mills county, Page county, Pottawattamie county

Digitaria filiformis (L.) Koeler
Rare southeast: Des Moines county, Jefferson county 1935, Lee county 1923 and Muscatine county 1898

Digitaria ischaemum (Schreber ex schweigger) Schreber ex Muhl.
Frequent to common throughout

Digitaria sanguinalis (L.) Scop.
Common throughout

Diodia teres Walter [incl. var. setifera Fern. & Grisc]
Rare east: Clinton County, Des Moines county, Dubuque county, Jackson county, Lee county, Louisa county and Muscatine county 1924

Dioscorea villosa L.
Common northwest; infrequent to rare elsewhere

Diospyros virginiana L.
Rare southeast and south central: Lee county, Louisa county, Marion county and Wayne county; possibly only the Lee county population is native

Diplotaxis muralis (L.) DC.
Rare central and north

Dipsacus laciniatus L.
Infrequent south; rare northeast and east central: Clinton County, Delaware County, Jackson county and Jones county

Dipsacus sylvestris Hudson
Rare escape from cultivation southern half

Dirca palustris L.
Frequent in Paleozoic Plateau, extreme east and central; rare to absent elsewh

Distichlis spicata (L.) Greene var. stricta (Torrey) Beetle
Rare western half, and in central: Tama county

Dodecatheon amethystinum Fassett
Rare northeast and east central: Allamakee County, Clayton County, Dubuque county, Jackson county and Winneshiek county

Dodecatheon meadia L. [incl. var. brachycarpum (Small) Fassett]
Common in Iowan Surface; infrequent southeast; rare in Des Moines lobe and in Paleozoic Plateau

Draba nemorosa L.
Rare northeast: Dubuque county

Draba reptans (Lam.) Fern. [incl. var. micrantha (Nutt.) Fern.]
Frequent in sandy places throughout

Draba verna L.
Rare northeast: Buchanan County

Dracocephalum parviflorum Nutt.
Rare north, east central and south central

Drosera rotundifolia L.
Rare north central: Hancock county

Dryopteris cristata (L.) Gray
Rare eastern half

Dryopteris goldiana (Hooker) Gray
Frequent northeast; rare central and south central

Dryopteris intermedia (Wilid.) Gray
Rare central and northeast: Allamakee County, Clayton County, Dubuque county and Webster county 1903

Dryopteris marginalis (L.) Gray
Rare central and northeast: Allamakee County, Dubuque county 1922 and Hardin county

Dryopteris triploidea Wherry
Rare northeast: Allamakee County, Clayton County and Dubuque county; discovered 1979

Dryopteris X boottii (Tuckerman) Underw.
Common northeast; infrequent southeast; rare central

Dryopteris X boottii (Tuckerman) Underw.
Rare northeast: Allamakee County 1980

Dryopteris X uliginosa (A. Br.) Druce
Rare east central: Jackson county 1980

Dulichium arundinaceum (L.) Britton
Rare north central, northeast, southeast and south central

Dyssodia papposa (Vent.) A. S. Hitchc.
Infrequent northwest and southern half of state

Echinacea angustifolia DC.
Common in Loess Hills of west; rare in west and south

Echinacea pallida Nutt.
Common west; infrequent elsewhere

Echinacea purpurea (L.) Moench
Rare in southeast and south central

Echinochloa crusgalli (L.) Beauv.
Common throughout

Echinochloa muricata (Beauv.) Fern. [incl. var. microstachya Wieg.]
Frequent to common throughout

Echinochloa walteri (Pursh) Heller
Rare southeastern quarter

Echinocystis lobata (Michx.) T. & G.
Frequent northwest; infrequent to rare elsewhere

Echinodorus cordifolius (L.) Griseb.
Infrequent southwest; rare northwest, northeast and southeast

Echinops sphaerocephalus L.
Rare northwest and northeast: Bremer County and Clay County 1923

Echium vulgare L.
Rare southwest

Eclipta alba (L.) Hassk.
Frequent eastern half; rare north central

Elaeagnus angustifolia L.
Infrequent escape from cultivation throughout

Elaeagnus umbellata Thunb.
Occasional escape from cultivation

Elatine triandra Schkuhr
Rare northwest: Dickinson county

Eleocharis acicularis (L.) R. & S.
Frequent to infrequent throughout most of state

Eleocharis atropurpurea (Retz.) Kunth
Rare southeast: Jefferson county 1933, Louisa county and Muscatine county

Eleocharis compressa Sulliv.
Infrequent to rare throughout most of state

Eleocharis engelmannii Steudel
Common in Paleozoic Plateau; frequent north central and south central; infrequent to rare elsewhere

Eleocharis erythropoda Steudel
Frequent to common western half; infrequent to rare eastern half

Eleocharis macrostachya Britton
Frequent to common north central and south central; infrequent to rare east

Eleocharis obtusa (Wilid.) Schultes
Common in Paleozoic Plateau; infrequent to frequent elsewhere

Eleocharis olivacea Torrey
Rare east central: Johnson county

Eleocharis ovata (Roth) R. & S.
Rare north central: Hancock county

Eleocharis parvula (R. & S.) Link var. anachaeta (Torrey) Svenson
Rare northwest: Clay County 1936 and Palo Alto county 1940

Eleocharis pauciflora (Lightf.) Link
Rare northwest: Dickinson county and Emmet county

Eleocharis smallii Britton
Frequent to common north central; infrequent to rare northeast

Eleocharis tenuis (Willd.) Schultes [incl. var. verrucosa (Svenson) Svenson]
Rare throughout most of state

Eleocharis wolfii Gray
Rare northwest, east central and southwest: Cedar County, Emmet county 1886, Johnson county and Union county

Eleocharis xyridiformis Fern. & Brackett
Rare southwest: Page county

Eleusine indica (L.) Gaertner
Frequent southern half; rare northern half

Ellisia nyctelea L.
Frequent to common throughout

Elodea canadensis Michx.
Common in lakes area; infrequent remainder of northern half; rare east

Elodea nuttallii (Planchon) St. John
Frequent southeast; infrequent to rare elsewhere

Elymus canadensis L.
Common throughout

Elymus interruptus Buckley
Rare northwest: Dickinson county, Emmet county 1922

Elymus riparius Wieg.
Rare and local central and northeast

Elymus villosus Muhl. ex Willd.
Frequent to common throughout

Elymus virginicus L.
Frequent to common throughout

Elymus wiegandii Fern.
Rare throughout

Elymus X maltei Bowden
Rare in scattered locations

Epilobium angustifolium L.
Infrequent northeastern quarter; rare north central

Epilobium ciliatum Raf.
Common southwest; infrequent to rare elsewhere

Epilobium coloratum Biehler
Frequent to common throughout; not reported from extreme west

Epilobium leptophyllum Raf.
Frequent in lakes area; otherwise rare to infrequent northern half

Epilobium strictum Muhl.
Rare northeast: Black Hawk County, Bremer County, Buchanan County and Chickasaw County

Epilobium X wisconsinense Ugent
Rare northwest: Lyon county 1910

Equisetum arvense L.
Common throughout

Equisetum fluviatile L.
Rare northeast half

Equisetum hyemale L. var. affine (Engelm.) A. A. Eaton
Frequent to common throughout

Equisetum laevigatum A. Br.
Infrequent east; common elsewhere

Equisetum pratense Ehrh.
Frequent northeast; rare central and east central

Equisetum scirpoides Michx.
Rare northeast and east central: Allamakee County, Clayton County, Delaware County, Dubuque county, Jackson county and Winneshiek county

Equisetum sylvaticum L.
Rare central, northeast and east central

Equisetum X ferrissii Clute
Common northwest and north central; infrequent to frequent elsewhere

Equisetum X litorale Kuhl. ex Rupr.
Rare north and east: Allamakee County, Clinton County, Des Moines county, Dickinson county, Jackson county and Mitchell county

Eragrostis capillaris (L.) Nees
Rare in Paleozoic Plateau, north central, southeast and south central

Eragrostis cilianensis (All.) Link ex E. Mosher
Common throughout

Eragrostis frankii C. A. Meyer ex Steudel
Rare west; infrequent elsewhere

Eragrostis frankii C. A. Meyer var. brevipes Fassett
Rare east

Eragrostis hypnoides (Lam.) BSP.
Frequent to common throughout

Eragrostis pectinacea (Michx.) Nees
Common throughout

Eragrostis pilosa (L.) Beauv.
Rare southern half

Eragrostis poaeoides Beauv. ex R. & S.
Rare central and southeast

Eragrostis reptans (Michx.) Nees
Rare central: Hardin county n.d. (ca. 1905)

Eragrostis spectabilis (Pursh) Steudel
Rare northwest; infrequent elsewhere

Eragrostis trichodes (Nutt.) Wood
Rare: scattered in southern half

Erechtites hieracifolia (L.) Raf. ex DC.
Frequent to common southern half; rare north central

Erigeron annuus (L.) Pers.
Common throughout

Erigeron philadelphicus L.
Common north central; frequent elsewhere

Erigeron pulchellus Michx.
Common in Paleozoic Plateau; rare elsewhere

Erigeron strigosus Muhl. ex Willd.
Common throughout

Eriochloa villosa (Thunb.) Kunth
Rare: becoming established in scattered locations throughout

Eriophorum angustifolium Honck.
Infrequent northern half; rare south

Eriophorum gracile W. D. J. Koch
Rare central, northwest and north central: Cerro Gordo County 1917, Dickinson county, Emmet county 1893, Hancock county and Webster county 1905

Eriophorum virginicum L.
Rare northeast: Buchanan County

Erodium cicutarium (L.) L'Her.
Rare central and northwest: Buena Vista County 1920, Cherokee County 1924 and Story county 1914

Eruca sativa P. Miller
Rare escape from cultivation

Erucastrum gallicum (Wilid.) Schulz
Rare west central and northeast: Delaware County, Winneshiek county and Woodbury county

Eryngium yuccifolium Michx.
Infrequent to frequent throughout most of state; rare in western tier of counties

Erysimum asperum (Nutt.) DC.
Rare central, west central and southeast: Ida county 1925, Tama county 1895 and Van Buren county 1940

Erysimum cheiranthoides L.
Frequent to infrequent northern half; infrequent to rare southern half

Erysimum inconspicuum (S. Watson) MacM.
Rare western half, and in central, northwest and northeast: Chickasaw County 1926, Emmet county 1926, Webster county 1906

Erysimum repandum L.
Rare central, northwest and south: Decatur County, Fremont county, Jefferson county 1933, Lee county, Page county and Story county

Erythronium albidum Nutt. [incl. var. mesochoreum (Knerr) Rickett; E. mesochoreum Knerr]
Frequent throughout

Erythronium americanum Ker-Gawl.
Rare northwest, northeast and south central: Allamakee County, Dubuque county, Fayette county, Lucas county, Marion county, O'Brien county 1921 and Winneshiek county

Euonymus alatus (Thunb.) Sieb.
Rare central, east central and west central: Linn county, Webster county and Woodbury county

Euonymus atropurpureus Jacq.
Infrequent west; rare northeast; frequent elsewh

Eupatorium altissimum L.
Frequent south; rare to infrequent north

Eupatorium maculatum L. [incl. var. bruneri (Gray) Breitung]
Common in Paleozoic Plateau; frequent in Iowan Surface; infrequent north central and south central

Eupatorium perfoliatum L.
Infrequent southeast; frequent elsewhere

Eupatorium purpureum L.
Frequent to common throughout

Eupatorium rugosum Houtt.
Common throughout

Eupatorium serotinus Michx.
Frequent southeast; rare southwest

Eupatorium sessilifolium L. var. brittonianum Porter
Rare northeast and east central: Allamakee County, Clayton County, Fayette county 1926 and Jones county 1948

Euphorbia commutata Engelm.
Rare northeast: Winneshiek county 1933

Euphorbia corollata L.
Infrequent northwest; common elsewhere

Euphorbia cyathophora Murray
Frequent to infrequent throughout

Euphorbia cyparissias L.
Frequent to infrequent throughout

Euphorbia dentata Michx.
Frequent to common northwest and southern half ; infrequent to rare elsewhere

Euphorbia esula L.
Frequent northwest; infrequent to rare elsewhere

Euphorbia falcata L.
Rare in Loess Hills: Monona county

Euphorbia geyeri Engelm.
Infrequent to rare eastern half

Euphorbia glyptosperma Engelm.
Frequent to common western half; infrequent to rare eastern half

Euphorbia hexagona Nutt. ex Sprengel
Rare western half; infrequent east

Euphorbia maculata L.
Infrequent west central, northwest and north central; common elsewhere

Euphorbia marginata Pursh
Common west, especially in Loess Hills; infrequent to rare southeast and south central

Euphorbia missurica Raf.
Rare central and west central: Harrison county and Story county 1880's

Euphorbia nutans Lag.
Infrequent north central; frequent to common elsewhere

Euphorbia obtusata Pursh
Rare southern two-thirds, and in northwest: Lyon county 1897

Euphorbia peplus L.
Rare southeast: Muscatine county 1891

Euphorbia prostrata Aiton
Rare west central and southwest: Harrison county, Mills county and Page county

Euphorbia serpens HBK.
Infrequent to rare western half

Euphorbia serpyllifolia Pers.
Infrequent northwest and north central; rare southwest

Euphorbia spathulata Lam.
Rare throughout most of state

Euphorbia stictospora Engelm.
Rare west central and northwest: Monona county, Plymouth county and Woodbury county

Euthamia graminifolia (L.) Nutt. ex Cass.
Rare extreme west; absent northeast; frequent to infrequent elsewhere

Fagopyrum esculentum Moench
Rare escape from cultivation throughout, not persisting

Falcaria sioides (Wibel) Ascherson
Rare west central: Guthrie county 1931

Festuca arundinacea Schreber
Rare: scattered locations in southeastern quarter

Festuca obtusa Biehler
Frequent to common throughout

Festuca octoflora Walter var. tenella (Willd.) Fern.
Rare southeast; infrequent elsewhere

Festuca ovina L.
Rare throughout

Festuca paradoxa Desv.
Rare southeastern half

Festuca pratensis Hudson
Infrequent throughout

Festuca rubra L.
Rare northeast, east central and south central: Allamakee County, Johnson county and Mahaska county 1915

Filipendula rubra (Hill) B. L. Robinson
Rare northeast and southeast: Fayette county and Muscatine county

Fimbristylis autumnalis (L.) R. & S. [incl. var. mucronulata (Michx.) Fern.]
Rare east

Floerkea proserpinacoides Willd.
Rare northeast: Dubuque county

Fragaria vesca L. var. americana Porter
Rare southeast; frequent to common elsewhere

Fragaria virginiana Duchesne [incl. var. illinoense (Prince) Gray; var. glauca S. Watson]
Common throughout

Fraxinus americana L.
Infrequent north central; absent northwest; frequent to common elsewhere

Fraxinus nigra Marsh.
Absent west; infrequent to rare southeast and south central; frequent to common elsewhere

Fraxinus pennsylvanica Marsh, var. lanceolata (Borkh.) Sarg.
Frequent to common throughout

Fraxinus pennsylvanica Marsh.
Common southwest; rare elsewhere

Fraxinus quadrangulata Michx.
Rare southeast: Des Moines county and Lee county

Froelichia floridana (Nutt.) Moq. var. campestris (Small) Fern.
Common southeast; frequent northeast

Froelichia gracilis (Hooker) Moq.
Rare central, east and south central

Fuirena simplex Vahl
Rare southwest: Fremont county 1946

Fumaria officinalis L.
Rare south central and southwest: adventive in Wayne county and Page county

Gaillardia pulchella Foug.
Rare west central and northwest: Emmet county 1954, Woodbury county

Galearis spectabilis (L.) Raf.
Frequent northeast; rare southwest; infrequent elsewhere

Galeopsis tetrohit L.
Rare west central, northeast and southwest

Galinsoga parviflora Cav.
Rare escape from gardens

Galinsoga quadriradiata Ruiz & Pavon
Frequent southwest; infrequent southeast; rare north central

Galium aparine L.
Common throughout

Galium asprellum Michx.
Rare northeast: Allamakee County, Clayton County, Delaware County, Dubuque county and Winneshiek county

Galium boreale L. [incl. var. intermedium DC; var. hyssopifolium (Hoffm.) DC]
Common northeastern quarter; frequent extreme east; infrequent northwest

Galium circaezans Michx. [incl. var. hypomalacum Fern.]
Frequent to common throughout

Galium concinnum T. & G.
Common throughout

Galium labradoricum (Wieg.) Wieg.
Rare north central and northeast: Cerro Gordo County, Chickasaw County, Clayton County, Mitchell county, Winnebago county and Winneshiek county

Galium obtusum Bigelow
Frequent to infrequent throughout

Galium tinctorium L.
Frequent to infrequent eastern half; rare south central

Galium trifidum L.
Rare north central and northeast: Des Moines lobe and Allamakee County, Winneshiek county

Galium triflorum Michx.
Frequent northwest; infrequent north central; common elsewhere

Galium verum L.
Rare west: Cass County 1925, Dickinson county, and Greene county 1929

Gaura biennis L. [incl. var. pitcheri T. & G.]
Frequent to common southern half; infrequent to rare northeastern quarter; rare northwest: Emmet county

Gaura coccinea Pursh
Frequent in Loess Hills

Gaura parviflora Douglas
Infrequent in Loess Hills of southwest; rare southeast, and in central and east central: Iowa county 1940 and Story county 1892

Gaylussacia baccata (Wang.) K. Koch
Rare northeast, east central and southeast: Allamakee County, Cedar County, Clinton County, Linn county and Muscatine county

Gentiana alba Muhl.
Infrequent to rare throughout most of state; not reported northwest

Gentiana andrewsii Griseb.
Frequent in Iowan Surface and central; infrequent to rare east and south central

Gentiana puberulenta J. Pringle
Infrequent to rare throughout most of state; frequent north central

Gentiana X billingtonii Farw.
Rare north central, northeast, east central and south central: Decatur County, Dubuque county and Johnson county

Gentianella quinquefolia (L.) Small ssp. occidentalis (A. Gray) J. Gillett
Infrequent to rare northeastern half

Gentianopsis crinita (Froel.) Ma
Rare north central, northeast and in lakes area

Gentianopsis procera (Holm) Ma
Rare north, and in central: Marshall county 1902

Geranium bicknellii Britton
Rare central, northwest and northeast: Emmet county 1922, Fayette county 1893 and Webster county 1905

Geranium carolinianum L. [incl. var. confertifolium Fern.]
Frequent to rare southwest; infrequent to rare elsewhere

Geranium maculatum L.
Not reported northwest; common elsewhere

Geum aleppicum Jacq. var. strictum (Aiton) Fern.
Infrequent to rare northeast, and in northwest: Dickinson county

Geum canadense Jacq. [incl. var. camporum (Rydb.) Fern. & Weath.]
Common throughout

Geum laciniatum Murray [incl. var. trichocarpum Fern.]
Rare northwest; frequent to infrequent south and east

Geum triflorum Pursh
Infrequent northeast; rare northwest: Dickinson county

Geum vernum (Raf.) T. & G.
Rare northwest and south: Jefferson county 1928, Mahaska county 1938, Page county, Taylor county and Wapello county 1939

Glechoma hederacea L. [incl. var. micrantha Moric]
Rare northwest; infrequent southwest; frequent to common elsewhere

Gleditsia triacanthos L.
Common throughout most of state; infrequent northwest

Glyceria borealis (Nash) Batchelder
Infrequent in lakes area; rare north central and east central: Hancock county and Linn county

Glyceria grandis S. Watson
Common in lakes area; frequent in remainder of northern half

Glyceria septentrionalis A. S. Hitchc.
Infrequent central and southeast

Glyceria striata (Lam.) A. S. Hitchc.
Frequent to common southern half and in lakes area; infrequent elsewhere

Glycine max (L.) Merr.
Common, widely cultivation, not persisting

Glycyrrhiza lepidota Pursh
Frequent to common western half; waif along railroads in eastern half

Gnaphalium obtusifolium L.
Common eastern half and south central; rare north central

Gnaphalium purpureum L.
Rare southeast and south central: Decatur County, Lee county 1931 and Warren county

Goodyera pubescens (Willd.) R. Br.
Rare and local east

Gratiola neglecta Torrey
Frequent south central; infrequent to rare elsewhere

Gratiola virginiana L.
Rare southeast and south central: Decatur County 1900, Lee county and Muscatine county

Grindelia squarrosa (Pursh) Dunal
Frequent to common west, especially in Loess Hills; infrequent to rare elsewhere

Gutierrezia dracunculoides (DC.) Blake
Rare southwest: Ringgold county

Gymnocarpium dryopteris (L.) Newman
Rare in Paleozoic Plateau and in central and east central: Hardin county and Johnson county 1892

Gymnocarpium robertianum (Hoffm.) Newman
Rare northeast: Allamakee County, Clayton County, Dubuque county and Winneshiek county

Gymnocladus dioica (L.) K. Koch
Frequent to infrequent throughout

Hackelia deflexa (Wahl.) Opiz var. americana (Gray) Fern. & I. M. Johnston
Frequent east; infrequent to rare north central and northeast

Hackelia virginiana (L.) I. M. Johnston
Common in Paleozoic Plateau and east; infrequent to frequent elsewhere

Hamamelis virginiana L.
Infrequent extreme east, except common in Paleozoic Plateau

Hedeoma hispidum Pursh
Frequent to common throughout

Hedeoma pulegioides (L.) Pers.
Common southeast; infrequent to rare extreme east, south central and southwest

Hedyotis crassifolia Raf.
Infrequent east

Hedyotis nigricans (Lam.) Fosb.
Frequent to common in Loess Hills and southwest

Helenium amarum (Raf.) H. Rock.
Rare east central: Jones county

Helenium autumnale L.
Frequent to common throughout

Heleochloa schoenoides (L.) Host
Rare central: Polk county

Helianthemum bicknellii Fern.
Frequent to common southern half and northeast; infrequent north central and in lakes area

Helianthemum canadense (L.) Michx.
Common northeast; frequent southwest; rare southeast

Helianthus annuus L.
Common western half; frequent eastern half

Helianthus decapetalus L.
Infrequent to rare northeastern quarter and southern half

Helianthus divaricatus L.
Rare extreme east

Helianthus gigonteus L.
Rare southeast and south central

Helianthus grosseserratus Martens
Frequent to common throughout

Helianthus hirsutus Raf.
Rare north central, southeast and southwest

Helianthus maximiliani Schrader
Common north central; infrequent west

Helianthus mollis Lam.
Rare southeast and south central: Decatur County and Muscatine county 1896

Helianthus occidentalis Riddell
Common in Paleozoic Plateau; infrequent remainder of east

Helianthus petiolaris Nutt.
Rare south central and southwest; frequent southeast

Helianthus rigidus (Cass.) Desf.
Common western half; infrequent eastern half

Helianthus rigidus (Cass.) Desf. ssp. subrhomboideus (Rydb.) Heiser
Common west; infrequent east

Helianthus strumosus L.
Rare northwest; frequent elsewhere

Helianthus tuberosus L.
Infrequent north; frequent to common south

Heliopsis helianthoides (L.) SWeet [incl. var. scabra (Dunal) Fern.]
Frequent to common throughout

Hemerocallis fulva (L.) L.
Common escape from cultivation throughout

Hemicarpha micrantha (Vahl) Pax
Rare north central and northeast; infrequent southeast

Hepatica nobilis P. Miller var. acuta (Pursh) Steyerm.
Common east and north central; frequent south central; rare northwest

Hepatica nobilis P. Miller var. obtusa (Pursh) Steyerm.
Rare northeast and southeast: Allamakee County and Henry county 1942

Heracleum lanatum Michx.
Frequent north central; infrequent western half; rare east

Hesperis matronalis L.
Infrequent to rare western half and east

Heteranthera dubia (Jacq.) MacM.
Infrequent northwest and east; rare elsewhere

Heteranthera limosa (SW.) Willd.
Rare northwest, southeast and southwest: Fremont county 1888, Lyon county and Muscatine county 1894

Heteranthera reniformis R. & P.
Rare south central: Lucas county

Heterotheca villosa (Pursh) Shinners [incl. var. angustifolia (Rydb.) Harms; var. camporum (Greene) Wunderlin; var. hispida (Hooker) Harms]
Rare northwest and east central: Clinton County, Jackson county and Lyon county

Heuchera americana L. var. hirsuticaulis (Wheelock) Rosend., Butters & Lak.
Rare southeast

Heuchera richardsonii R. Br. [incl. var. hispidior Rosend., Butters & Lak.]
Common northeastern quarter and southwest; infrequent to frequent elsewh

Hibiscus laevis All.
Frequent to infrequent east central, southeast and south central; rare north central, southwest and in Paleozoic Plateau

Hibiscus trionum L.
Rare northeast; frequent to common elsewhere

Hieracium aurantiacum L.
Rare north central and northeast: Allamakee County, Clayton County 1935 and Mitchell county

Hieracium canadense Michx. [incl. var. fasciculatum (Pursh) Fern.]
Rare north, and in east central and southeast: Linn county, Muscatine county and Scott county late 1800's

Hieracium longipilum Torrey
Infrequent in Paleozoic Plateau; rare remainder of eastern half

Hieracium scabrum Michx.
Frequent south and in Paleozoic Plateau; rare to infrequent elsewhere

Hieracium umbellatum L.
Common in Paleozoic Plateau; infrequent remainder of north; rare southeast

Hierochloe odorata (L.) Beauv.
Infrequent northern half

Hippuris vulgaris L.
Rare northwest and north central: Cerro Gordo County 1903, Clay County 1936 and Dickinson county 1948

Holcus lanatus L.
Rare central, east central and southeast: Linn county 1919, Louisa county 1919 and Story county 1898

Holosteum umbellatum L.
Rare west central, northeast and southeast: Des Moines county, Dubuque county and Woodbury county

Hordeum jubatum L.
Common throughout

Hordeum pusillum Nutt.
Infrequent to frequent south; rare north

Hordeum vulgare L.
Infrequent escape from cultivation throughout but not persisting

Hudsonia tomentosa Nutt.
Rare east central: Jackson county

Humulus japonicus Sieb. & Zucc.
Frequent southwest; infrequent to rare eastern two-thirds

Humulus lupulus L.
Infrequent to frequent throughout most of state

Hybanthus concolor (T. F. Forster) Sprengel
Rare central, northeast and east central: Allamakee County, Boone County, Clayton County, Dubuque county, Jones county and Winneshiek county

Hydrastis canadensis L.
Rare northeast and east central

Hydrophyllum appendiculatum Michx.
Frequent in Paleozoic Plateau; infrequent southern half, east central and southeast; rare elsewhere

Hydrophyllum virginianum L.
Common northwestern half; frequent southeastern half

Hypericum boreale (Britton) Bickn.
Rare east central: Linn county

Hypericum canadense L.
Rare northeast: Winneshiek county 1933

Hypericum drummondii (Grev. & Hooker) T. & G.
Rare southeast: Van Buren county 1933

Hypericum gentianoides (L.) BSP.
Rare east and south central: Buchanan County, Clinton County 1932, Madison county 1917 and Muscatine county pre-1900

Hypericum majus (Gray) Britton
Infrequent to rare throughout most of state

Hypericum mutilum L.
Frequent southeast; infrequent south central; rare northeastern quarter

Hypericum perforatum L.
Frequent southwest; infrequent to rare elsewhere

Hypericum prolificum (Spach) Steudel
Frequent southeast; rare south central and southwest

Hypericum punctatum Lam.
Frequent to common south and in Iowan Surface; rare north central and in Paleozoic Plateau

Hypericum pyramidatum Alton
Frequent to infrequent northern half; infrequent to rare southern half

Hypericum sphaerocarpum Michx.
Frequent to common eastern half; rare northwest and southwest: Fremont county 1890, Palo Alto county 1939

Hypoxis hirsuta (L.) Cov.
Infrequent northeast; frequent to common elsewhere

Hystrix patula Moench
Rare northwest; common elsewhere

Iberis umbellata L.
Rare escape from cultivation in south central: Madison county 1942

Ilex verticillata (L.) Gray
Rare north central, northeast and east central: Allamakee County, Bremer County, Howard county, Linn county and Mitchell county

Impatiens capensis Meerb.
Frequent to common throughout

Impatiens pallida Nutt.
Infrequent northwest and north central; frequent to common elsewhere

Inula helenium L.
Rare east: Johnson county, Muscatine county and Winneshiek county

Iodanthus pinnatifidus (Michx.) Steudel
Rare to infrequent southern half and northeast

Ipomoea coccinea L.
Rare escape from cultivation

Ipomoea hederacea (L.) Jacq.
Frequent southwest; infrequent to rare elsewhere

Ipomoea lacunosa L.
Rare southwest and southeast: Des Moines county, Fremont county, Muscatine county 1891 and Page county

Ipomoea pandurata (L.) G. F. W. Meyer
Frequent southeast; rare northwest, northeast, east central and south central: Clayton County 1920, Decatur County 1898, Johnson county 1933, Linn county 1902, Lyon county 1896 and Winneshiek county

Ipomoea purpurea (L.) Roth
Frequent north central and south central; infrequent to rare elsewhere

Ipomopsis rubra (L.) Wherry
Rare escape from cultivation in north central, east central and southwest: Cerro Gordo County, Fremont county and Johnson county

Iris shrevei Small
Frequent to common throughout most of state; especially common in lakes area and north central

Iris X germanica L.
Rare: occasionally persists from cultivation

Isoetes melanopoda Gay & Dur.
Rare east central: Clinton County

Isopyrum biternatum (Raf.) T. & G.
Frequent to common central and northeast; infrequent to rare elsewhere

Iva annua L.
Rare southeast and southwest: Des Moines county, Jefferson county 1935 and Pottawattamie county 1898

Iva xanthifolia Nutt.
Frequent to infrequent western half and north central; rare southeast: Muscatine county 1892

Jeffersonia diphylla (L.) Pers.
Rare northeast: Allamakee County, Clayton County, Dubuque county and Fayette county

Juglans cinerea L.
Common east and north central; infrequent southwest

Juglans nigra L.
Common throughout

Juncus acuminatus Michx.
Infrequent southeast; rare northeast and southwest

Juncus alpinus Vill. var. fuscescens Fern.
Rare west central and northwest: Dickinson county, Harrison county 1909 and Woodbury county 1888

Juncus balticus Willd. var. littoralis Engelm.
Infrequent in lakes area; rare elsewhere

Juncus bufortius L.
Rare and scattered, north and southeast

Juncus canadensis J. Gay ex Laharpe
Rare south central and eastern quarter

Juncus dudleyi Wieg.
Frequent to common north central, south central and in lakes area; infrequent elsewhere

Juncus effusus L. [incl. var. solutus Fern. & Wieg.]
Rare east

Juncus greenei Oakes & Tuckerman
Rare northeast and east central

Juncus interior Wieg.
Frequent to common southern half; infrequent northern half

Juncus marginatus Rostk.
Rare east central and southeast: Cedar County, Clinton County, Muscatine county 1892 and Scott county

Juncus nodosus L.
Infrequent to rare throughout

Juncus tenuis Willd.
Rare northwest; common elsewhere

Juncus torreyi Cov.
Frequent to common western half; infrequent to rare eastern half

Juncus vaseyi Engelm.
Rare northeast: Black Hawk County and Howard county

Juncus X nodosiformis Fern.
Rare northwest: Dickinson county

Juniperus communis L. var. depressa Pursh
Infrequent northeast; rare central: Hardin county

Juniperus horizontalis Moench
Rare north central and northeast: Allamakee County and Floyd county

Juniperus virginiana L.
Common eastern half; infrequent to frequent west

Justicia americana (L.) Vahl
Rare southeast: Des Moines county, Henry county, Jefferson county 1935 and Lee county 1931

Kochia scoparia (L.) Schrader
Common north central and southwest; rare eastern half; infrequent elsewhere

Koeleria macrantha (Ledeb.) Schultes
Infrequent east; frequent to common elsewhere

Krigia biflora (Walter) Blake
Rare north; frequent east

Krigia dandelion (L.) Nutt.
Rare southwest: Union county

Krigia virginica (L.) Willd.
Rare east central and southeast: Des Moines county, Clinton County, Jackson county, Louisa county and Muscatine county

Kummerowia stipulacea (Maxim.) Makino
Common southeast; infrequent south central; rare northeast

Kummerowia striata (Thunb.) Schindl.
Rare southeast: Muscatine county

Lactuca biennis (Moench) Fern.
Common in lakes area; rare north central, and in northeast and east central: Jones county and Winneshiek county

Lactuca canadensis L. [incl. var. longifolia (Michx.) Farw.; var. obovata Wieg.; var. latifolia Kuntze]
Infrequent northwest; common elsewhere

Lactuca floridana (L.) Gaertner [incl. var. villosa (Jacq.) Cronq.]
Frequent to common southern half; infrequent to rare northern half

Lactuca ludoviciana (Nutt.) Riddell
Infrequent to frequent western half; rare or absent eastern half

Lactuca saligna L.
Rare southwest: Page county

Lactuca serriola L.
Common southwestern two-thirds; infrequent to rare elsewhere

Lactuca tatarica (L.) C. A. Meyer ssp. pulchella (Pursh) Stebbins
Common west; frequent to infrequent north central and south central

Lamium amplexicaule L.
Infrequent south and north central; rare northwest and northeast: Palo Alto county and Winneshiek county

Lamium purpureum L.
Rare central, east central and southeast: Des Moines county, Johnson county and Story county

Laportea canadensis (L.) Wedd.
Frequent northwest; common elsewhere

Lappula echinata Gilib.
Common northwest; infrequent to rare elsewhere

Lappula redowskii (Hornem.) Greene [incl. var. texana (Scheele) Brand]
Rare throughout

Lathyrus ochroleucus Hooker
Frequent north central; rare northeast and in Paleozoic Plateau

Lathyrus palustris L.
Common north central; infrequent to rare elsewhere

Lathyrus tuberosus L.
Rare southeast, and in southwest: Cass County and Adams County 1947

Lathyrus venosus Muhl. ex Willd.
Common northwest and north central; infrequent to absent elsewhere

Lechea intermedia Leggett
Rare west central, east central and northeast: Allamakee County, Benton County, Dubuque county, Guthrie county and Winneshiek county

Lechea racemulosa Michx.
Rare: old central (Webster county) collection, n.d.

Lechea stricta Leggett
Frequent to infrequent northeast; rare elsewhere

Lechea tenuifolia Michx.
Infrequent south central and southeast; rare north central and northeast

Lechea villosa Ell.
Rare east: Jefferson county 1946, Jones county, Lee county 1923 and Winneshiek county 1932

Leersia lenticularis Michx.
Rare eastern half

Leersia oryzoides (L.) SW.
Rare northwest; frequent to common elsewhere

Leersia virginica Willd.
Common in Paleozoic Plateau; infrequent to frequent elsewhere

Lemna minor L. [incl. i. turionifera Landolt]
Common throughout

Lemna perpusilla Torrey
Rare east central: Johnson county 1915

Lemna trisulca L.
Common in lakes area; infrequent to rare elsewhere

Leontodon autumnalis L.
Rare southwest: Page county

Leonurus cardiaca L.
Frequent to common throughout

Leonurus marrubiastrum L.
Frequent in southwest; rare north central, northeast and east central: Cedar County, Johnson county, Winneshiek county and Wright county

Leonurus sibiricus L.
Rare central: Poweshiek county

Lepidium campestre (L.) R. Br.
Frequent to infrequent southern half; rare north central and southeast

Lepidium densiflorum Schrader
Common northern half; frequent east and south central; rare southeast and southwest

Lepidium perfoliatum L.
Rare central and northwest: Cherokee County 1931 and Story county

Lepidium virginicum L.
Rare northwest; frequent to common elsewhere

Leptochloa fascicularis (Lam.) Gray [incl. var. acuminata (Nash) Gl.]
Rare to infrequent northwestern two-thirds of state

Leptoloma cognatum (Schultes) Chase
Frequent to common eastern quater; rare south central

Lespedeza capitata Michx.
Common throughout

Lespedeza cuneata (Dum.-Cours.) G. Don
Rare southern half

Lespedeza daurica (Laxm.) Schindl.
Rare southeast: Louisa county

Lespedeza leptostachya Engelm.
Rare central, north and south central

Lespedeza repens (L.) Barton
Rare southeast and south central: Henry county 1897, Mahaska county 1921 and Van Buren county 1932

Lespedeza violacea (L.) Pers.
Common southeast; infrequent central and south central; rare northeast and southwest

Lespedeza virginica (L.) Britton
Frequent southeast; rare south central and southwest

Lesquerella ludoviciana (Nutt.) S. Watson
Rare central and northeast: Black Hawk County 1921 and Hardin county 1905

Leucanthemum vulgare Lam.
Frequent to common southwest, south central and in Paleozoic Plateau; infrequent to rare remainder of northeast and southeast

Leucospora multifida (Michx.) Nutt.
Rare east: Fayette county 1894, Lee county n.d. (probably 1890's), Louisa county, Muscatine county and Scott county

Liatris aspera Michx.
Common eastern two-thirds; infrequent elsewhere

Liatris cylindracea Michx.
Rare northeastern third; frequent in Paleozoic Plateau

Liatris ligulistylis (A. Nelson) K. Schum.
Rare north central and northeast

Liatris punctata Hooker
Frequent to common northwest; infrequent rest of western half

Liatris pycnostachya Michx.
Rare or infrequent extreme west; frequent to common elsewhere

Liatris squarrosa (L.) Michx. [incl. var. hirsuta (Rydb.) Gaiser; var. glabrata (Rydb.) Gaiser]
Infrequent western half; rare southeast

Lilium lancifolium Thunb.
Rare escape from gardens

Lilium michiganense Farw.
Frequent to infrequent throughout

Lilium philadelphicum L. var. andinum (Nutt.) Ker-Gawl.
Infrequent to rare throughout

Linaria canadensis (L.) Dum.-Cours.
Infrequent e

Linaria macedonica Griseb.
Rare escape from cultivation in south central: Madison county 1942

Linaria vulgaris Hill
Frequent southeast and southwest; infrequent elsewhere

Lindernia anagallidea (Michx.) Pennell
Rare western two-thirds

Lindernia dubia (L.) Pennell
Common southern half and extreme east; frequent in Paleozoic Plateau; rare elsewhere

Linnaea borealis L. ssp. americana (Forbes) Hulten
Rare northeast: Clayton County and Winneshiek county

Linum medium (Planchon) Britton var. texanum (Planchon) Fern.
Rare southeast: Des Moines county 1925, Jefferson county 1933 and Lee county 1928

Linum perenne L.
Rare escape from cultivation

Linum rigidum Pursh [incl. var. compactum (A. Nelson) Rogers]
Frequent to rare west

Linum sulcatum Riddell
Common southwest; rare southeast; frequent to infrequent elsewhere

Linum usitatissimum L.
Rare escape from cultivation, not persisting

Liparis liliifolia (L.) L. C. Rich, ex Lindley
Infrequent east three-quarters

Liparis loeselii (L.) L. C. Rich.
Rare west central, north and east

Liriodendron tulipifera L.
Commonly planted in southeast; a population is reproducing in Lee county

Lithospermum arvense L.
Rare southeast and south central: Des Moines county 1937, Lee county, Mahaska county 1938 and Muscatine county 1892

Lithospermum canescens (Michx.) Lehm.
Common throughout

Lithospermum caroliniense (Walter) MacM.
Frequent to infrequent northeast; rare to infrequent southern half

Lithospermum incisum Lehm.
Common northern half and southwest; rare elsewhere

Lithospermum latifolium Michx.
Frequent northeastern quarter; infrequent to rare elsewhere

Lobelia cardinalis L.
Frequent northeast and southeast; infrequent south central; rare north central

Lobelia inflata L.
Frequent to common southeastern two-thirds

Lobelia kalmii L.
Rare north: Cerro Gordo County, Clayton County 1921, Clay County, Dickinson county, Emmet county, Howard county and Palo Alto county

Lobelia siphilitica L.
Infrequent northwest; frequent to common elsewhere

Lobelia spicata Lam. [incl. var. hirtella Gray; var. campanulata Mcvaugh; var. leptostachya (A. DC.) Mack. & Bush]
Common north and eastast; frequent to infrequent elsewhere

Lobularia maritima (L.) Desv.
Rare escape from cultivation in central, north central and east central: Cerro Gordo County, Linn county 1937, Poweshiek county, Tama county 1895

Lolium perenne L.
Infrequent to rare throughout

Lolium perenne L. var. italicum Parn.
Common southwest; rare north central and east

Lolium temulentum L.
Rare north central and northeast, not collected since 1922

Lomatium foeniculaceum (Nutt.) Coulter & Rose
Rare northwest and southwest: Fremont county, Lyon county and Sioux county

Lomatium orientale Coulter & Rose
Rare northwest and southwest: Cherokee County, Clay County 1942, Emmet county, Lyon county, O'Brien county, Sioux county and Union county 1926

Lonicera dioica L. var. glaucescens (Rydb.) Butters
Common north central, east and in Paleozoic Plateau; frequent southwest; infrequent to rare elsewhere

Lonicera morrowi Gray
Rare escape from cultivation throughout

Lonicera prolifera (Kirchner) Rehder
Common north central and northeast; infrequent to frequent southeast and south central; rare southwest

Lonicera sempervirens L.
Rare escape in northeast and south central: Delaware County 1891, Mahaska county late 1800's

Lonicera tatarica L.
Frequent escape from cultivation

Lotus corniculatus L.
Infrequent to rare throughout

Lotus purshianus Clem. & Clem.
Rare northwest, north central and southeast; no records since 1926

Ludwigia alternifolia L.
Infrequent southeast and south central

Ludwigia palustris (L.) Ell.
Rare east

Ludwigia peploides (HBK.) Raven ssp. glabrescens (Kuntze) Raven
Rare south: Fremont county, Louisa county and Lucas county

Ludwigia polycarpa Short & Peter
No records from west central; rare northwest and southwest; infrequent to frequent elsewhere

Lupinus perennis L. [incl. var. occidentalis S. Watson]
Rare northeast: Allamakee County and Winneshiek county 1893

Luzula acuminata Raf.
Infrequent e

Luzula multiflora (Retz.) Lej. [incl. var. bulbosa Wood]
Rare northeastern half

Lycium halimifolium P. Miller
Infrequent to rare escape in southern half

Lycopersicon esculentum P. Miller
Not persisting from cultivation

Lycopodium clavatum L.
Rare northeast and east central: Allamakee County, Iowa county and Johnson county

Lycopodium dendroideum Michx.
Rare northeast: Allamakee County, Clayton County and Dubuque county

Lycopodium digitatum A. Br.
Rare northeast and east central

Lycopodium inundatum L.
Rare northeast: Buchanan County

Lycopodium lucidulum Michx.
Rare central, northeast and east central

Lycopodium porophilum Lloyd & Underw.
Rare northeast: Allamakee County, Clayton County and Delaware County 1930

Lycopodium X bartleyi Cusick
Rare northeast: Allamakee County and Clayton County

Lycopus americanus Muhl. ex Barton
Rare in Paleozoic Plateau; infrequent northwest and extreme east; common elsewhere

Lycopus asper Greene
Infrequent west; rare in lakes area and extreme east

Lycopus uniflorus Michx.
Frequent northern half; rare elsewhere

Lycopus virginicus L.
Not reported northwest; infrequent to rare elsewhere

Lygodesmia juncea (Pursh) D. Don
Common in Loess Hills; frequent to infrequent northwest

Lygodesmia rostrata Gray
Rare west central and northwest: Harrison county and Plymouth county 1927

Lysimachia ciliata L.
Infrequent to common throughout

Lysimachia clethroides Duby
Rare escape from cultivation

Lysimachia hybrida Michx.
Rare central and northwest; frequent to common elsewhere

Lysimachia lanceolata Walter
Frequent to infrequent northern half

Lysimachia nummularia L.
Frequent northeastern quarter; infrequent north central; rare southeast and south central

Lysimachia punctata L.
Rare escape from cultivation

Lysimachia quadriflora Sims
Common north central; frequent northeastern quarter; infrequent to rare northwest, east central and southeast

Lysimachia terrestris (L.) BSP.
Not reported from northwest; infrequent to rare elsewhere

Lysimachia thyrsiflora L.
Infrequent north central and in lakes area; rare northeast and southeast

Lythrum alatum Pursh
Common in lakes area; infrequent to rare elsewhere

Lythrum salicaria L.
Rare throughout, escaping from cultivation and spreading rapidly

Machaeranthera spinulosa Greene
Common southwest; frequent west central and northwest

Maclura pomifera (Raf. ex Sarg.) Schneider
Common escape from cultivation, especially in southern half

Madia sativa Molina var. congesta T. & G.
Rare waif from western plains in northwest and south central: Emmet county and Mahaska county 1930's

Maianthemum canadense Desf. [incl. var. interius Fern.]
Common in Paleozoic Plateau, rare in remainder of east

Malaxis unifolia Michx.
Rare central and east: Iowa county 1923, Johnson county 1907, Muscatine county 1893, Story county 1897, Tama county n.d. (pre-1900) and Winneshiek county 1879

Malus ioensis (Wood) Britton
Frequent to common throughout

Malus sylvestris (L.) P. Miller
Rarely escaping from cultivation

Malva neglecta Wallr.
Common southwestern half; infrequent to rare elsewhere

Malva parviflora L.
Rare northwest: Emmet county

Malva rotundifolia L.
Frequent to common throughout

Malva sylvestris L.
Rare escape from cultivation, no records since 1924

Malva verticillata L.
Rare escape from cultivation, last record in 1929

Malvastrum hispidum (Pursh) Hochr.
Rare east central and southeast: Muscatine county 1895 and Scott county 1898

Marrubium vulgare L.
Infrequent south and east central

Marsilea quadrifolia L.
Rare southeast and south central: Decatur County and Van Buren county

Marsilea vestita Hooker & Grev.
Rare northwest: Lyon county

Matricaria chamomilla L.
Rare east central and southeast: Johnson county 1927 and Muscatine county 1895, Scott county

Matricaria maritima L.
Rare southeast: Muscatine county 1925

Matricaria matricarioides (Less.) Porter
Frequent to common northeastern two-thirds; infrequent w

Matteuccia struthiopteris (L.) Todaro var. pensylvanica (Willd.) Morton
Infrequent to frequent east; rare elsewhere

Medicago folcata L.
Rare central and west: Lyon county, Marshall county, Page county, Sac county and Sioux county

Medicago lupulina L.
Frequent to common throughout

Medicago sativa L.
Common escape from cultivation

Megalodonta beckii (Torrey ex Sprengel) Greene
Rare northwest and north central: Cerro Gordo County 1901 and Dickinson county

Melanthium virginicum L.
Infrequent central, southeast and south central; rare northeast

Melica mutica Walter
Rare southwest: Union county 1898

Melica nitens (Scribner) Nutt. ex Piper
Rare central and east

Melilotus alba Medicus
Common throughout

Melilotus officinalis (L.) Pallas
Common throughout

Menispermum canadense L.
Frequent to common throughout

Mentha arvensis L. [incl. var. villosa (Bentham) Stewart; var. glabrata (Bentham) Fern.]
Rare northwest; infrequent in Iowan Surface; frequent to common elsewhere

Mentha spicata L.
Frequent cultivation, occasionally escaping or persisting

Mentha X gentilis L.
Frequent cultivation, occasionally escaping or persisting

Mentha X piperita L.
Frequent cultivation, occasionally escaping or persisting

Mentzelia decapetala (Pursh) Urban & Gilg
Rare west central and northwest: Harrison county, Plymouth county and Woodbury county

Menyanthes trifoliata L.
Rare northern half, and in southeast: Muscatine county

Mertensia paniculata (Aiton) G. Don
Rare northeast: Allamakee County, Clayton County, Fayette county, Howard county and Winneshiek county

Mertensia virginica (L.) Pers. ex Link
Frequent to infrequent eastern half; rare western half

Milium effusum L.
Rare northeast: Allamakee County

Mimulus alatus Aiton
Rare southeast and south central

Mimulus glabratus HBK. var. fremontii (Bentham) Grant
Rare north, east and southwest

Mimulus ringens L. [incl. var. minthodes (Greene) Grant]
Infrequent northwest; common elsewhere

Minuartia michauxii (Fern.) Farw.
Rare northeast and east central: Allamakee County, Clinton County, Delaware County, Dubuque county, Jackson county, Jones county and Winneshiek county 1899

Mirabilis albida (Walter) Heimerl
Rare northwest, north central and south central

Mirabilis hirsuta (Pursh) MacM.
Frequent to infrequent western half

Mirabilis nyctaginea (Michx.) MacM.
Common throughout

Miscanthus sacchariflorus (Maxim.) Hackel
Infrequent escape throughout, but increasing in abundance

Mitchella repens L.
Rare northeast: Dubuque county 1901 and Winneshiek county

Mitella diphylla L.
Frequent to common northeastern quarter; infrequent north central; rare southeast and south central

Mitella nuda L.
Rare northeast: Allamakee County

Moehringia lateriflora (L.) Fenzl
Frequent in Paleozoic Plateau and in Iowan Surface; infrequent southeast

Mollugo verticillata L.
Frequent to common throughout

Monarda didyma L.
Rare east: Allamakee County 1922, Lee county 1924 and Scott county 1880's

Monarda fistulosa L. [incl. var. mollis (L.) Bentham]
Common throughout

Monarda punctata L. var. villicaulis (Pennell) Shinners
Frequent to common east and in Paleozoic Plateau; rare south central, southwest and in Iowan Surface

Monolepis nuttalliana (Roemer & Schultes) Greene
Rare southwest and central: Page county and Story county 1917

Monotropa hypopithys L.
Rare northeast, southeast and south central: Allamakee County, Appanoose County, Clayton County 1921, Dubuque county, Lee county and Winneshiek county 1903

Monotropa uniflora L.
Infrequent to rare throughout most of state

Montia chamissoi (Ledeb. ex Sprengel) Greene
Rare northeast: Fayette county 1898

Morus alba L.
Common throughout

Morus rubra L.
Infrequent to frequent southwestern half

Muhlenbergia asperifolia (Nees & Meyer) Parodi
Rare central, west central and northwest: Boone County, Clay County 1948, Dickinson county, Monona county, Story county 1923 and Woodbury county

Muhlenbergia bushii Pohl
Rare southwest and southeastern quarter

Muhlenbergia cuspidata (Torrey) Rydb.
Common in lakes area and in Loess Hills; rare central and northeast

Muhlenbergia frondosa (Poiret) Fern.
Infrequent to rare west; frequent to common elsewhere

Muhlenbergia glomerata (Willd.) Trin.
Rare north central and east

Muhlenbergia mexicana (L.) Trin.
Common north central; infrequent to rare elsewhere

Muhlenbergia racemosa (Michx.) BSP.
Frequent to common throughout

Muhlenbergia Schreberi J. F. Gmelin
Frequent southeastern two-thirds

Muhlenbergia sobolifera (Muhl. ex Willd.) Trin.
Infrequent to rare southeastern two-thirds

Muhlenbergia sylvatica (Torrey) Torrey ex Gray
Rare east

Muhlenbergia tenuiflora (Willd.) BSP.
Rare east and south central

Myosotis micrantha Pallas
Rare northeast: Dubuque county

Myosotis verna Nutt.
Infrequent to rare southeastern two-thirds

Myosoton aquaticum (L.) Moench
Rare north central, northeast and east central

Myosurus minimus L.
Infrequent east central and south

Myriophyllum exalbescens Fern.
Infrequent north central, in Iowan Surface and in lakes area; rare south central and southwest

Myriophyllum heterophylum Michx.
Rare central, northwest and north central: Clay County 1895, Dickinson county 1901, Emmet county, Palo Alto county 1938, Webster county 1905 and Winnebago county

Myriophyllum pinnatum (Walter) BSP.
Rare northeast and south: Decatur County 1899, Dubuque county 1900, Fremont county, Lee county, Lucas county, Muscatine county and Ringgold county 1898

Myriophyllum spicatum L.
Rare: Hancock county

Myriophyllum verticillatum L.
Rare central, northwest and northeast: Black Hawk County, Dickinson county, Emmet county, Palo Alto county 1938 and Webster county 1906

Najas flexilis (Willd.) Rostk. & schmidt
Frequent southeast and in lakes area of northwest; rare elsewhere

Najas guadalupensis (Sprengel) Magnus
Frequent to infrequent in lakes area of northwest, and also north central, southeast and south central; rare elsewhere

Napaea dioica L.
Rare north central and northeast: Allamakee County, Black Hawk County, Butler County, Fayette county, Floyd county n.d., Howard county and Winneshiek county

Nasturtium officinale R. Br.
Common northeast; widely distributed

Navarretia intertexta (Bentham) Hooker
Rare northwest, and in southwest: Page county 1920

Nelumbo lutea (Willd.) Pers.
Frequent to rare in Mississippi R. basin; rare along Missouri R.; introduced into a few interior lakes

Nepeta cataria L.
Frequent to common throughout

Neslia paniculata (L.) Desv.
Rare central, east central and southwest: Johnson county 1908, Linn county 1949, Mills county 1925 and Webster county 1906

Nicandra physalodes (L.) Gaertner
Rare central, northeast and southeast: Allamakee County, Keokuk county, Muscatine county and Story county

Nothocalais cuspidata (Pursh) Greene
Frequent northwest and north central; infrequent west central and southwest

Nuphar luteum (L.) Sibth. & Smith ssp. variegatum (Engelm. ex Dur.) E. O. Beal
Not reported from southwest; infrequent to rare elsewhere

Nymphaea tuberosa Paine
Frequent in lakes area; infrequent to rare elsewhere

Oenothera biennis L. ssp. centralis Munz
Infrequent to rare eastern half

Oenothera laciniata Hill
Frequent to infrequent southeastern third; rare northwest, south central and southwest

Oenothera parviflora L.
Rare central, north central, northeast and southeast

Oenothera perennis L.
Rare northeast and east central: Delaware County, Fayette county, Howard county, Linn county and Winneshiek county

Oenothera pilosella Raf.
Infrequent southeastern half

Oenothera rhombipetala Nutt. ex T. & G.
Frequent east; infrequent to rare central and south central

Oenothera speciosa Nutt.
Rare north central and south: Clarke County, Fremont county, Kossuth county and Van Buren county

Oenothera villosa Thunb.
Common throughout

Onoclea sensibilis L.
Frequent to common east; infrequent west

Onopordum acanthium L.
Rare central and northeast: Fayette county 1929, Hardin county 1939

Onosmodium molle Michx. var. hispidissimum (Mack.) Cronq.
Rare northeast and southeast

Onosmodium molle Michx. var. occidentale (Mack.) I. M. Johnston
Frequent to common west; rare east

Ophioglossum pus ilium Raf.
Rare central, northeast and east central

Opuntia fragilis (Nutt.) Haw.
Rare central, northwest and northeast: Buchanan County, Hardin county and Lyon county

Opuntia humifusa (Raf.) Raf.
Rare east and south

Opuntia macrorhiza Engelm.
Rare southwest, west central, central, and northeast: Allamakee County, Guthrie county Montgomery county, Page county and Polk county

Orbexilum onobrychis (Nutt.) Rydb.
Rare southeast: Des Moines county and Lee county 1931

Ornithogalum umbellatum L.
Rare escape from cultivation

Orobanche fasciculata Nutt.
Rare northwest and northeast: Allamakee County and Dickinson county 1933

Orobanche ludoviciana Nutt.
Rare northwest: Lyon county 1896

Orobanche uniflora L.
Rare southeastern third, and in west central: Guthrie county

Oryzopsis asperifolia Michx.
Rare northeast: Allamakee County, Clayton County, Delaware County, Dubuque county and Winneshiek county

Oryzopsis pungens (Torrey ex Sprengel) A. S. Hitchc.
Rare northeast: Allamakee County and Clayton County

Oryzopsis racemosa (Smith) Ricker
Common in Paleozoic Plateau and extreme east; rare elsewhere in northeastern two-thirds

Osmorhiza claytonii (Michx.) C. B. Clarke
Common eastern half; infrequent western half

Osmorhiza longistylis (Torrey) DC. [incl. var. villicaulis Fern.; var. brachycoma Blake]
Infrequent southwest; frequent to common elsewhere

Osmunda cinnamomea L.
Rare east: Clayton County 1945, Delaware County, Henry county 1938, Jackson county 1905 and Muscatine county

Osmunda claytoniana L.
Frequent east; infrequent central

Osmunda regalis L. var. spectabilis (Willd.) Gray
Rare east: Allamakee County, Cedar County, Clinton County, Delaware County, Jones county and Muscatine county

Ostrya virginiana (P. Miller) K. Koch
Frequent to common throughout

Oxalis dillenii Jacq.
Infrequent to rare east and south central

Oxalis stricta L.
Frequent southern half; infrequent extreme east and northwest; common northeast

Oxalis violacea L.
Infrequent southwestern quarter; frequent to common elsewhere

Oxypolis rigidior (L.) Raf.
Rare west, northwest and south; infrequent elsewhere

Oxytropis lambertii Pursh
Infrequent west except common in Loess Hills

Panax quinquefolius L.
Frequent northeast and east central; infrequent southeast; rare western half

Panicum capillare L.
Common throughout

Panicum dichotomiflorum Michx.
Infrequent west and northeast; frequent to common elsewhere

Panicum gattingeri Nash
Rare northwest and southeast: Clay County, Dickinson county and Louisa county

Panicum hillmanii Chase
Rare northwest: Pocahontas county

Panicum miliaceum L.
Rare to infrequent southwestern two-thirds

Panicum philadelphicum Bernh. ex Trin.
Rare west, north central and south central: Clay County, Dickinson county 1948, Greene county, Hancock county, Monroe county and Montgomery county

Panicum virgatum L.
Common throughout

Parietaria pensylvanica Muhl. ex Willd.
Infrequent northeast; frequent to common elsewhere

Parnassia glauca Raf.
Rare northeastern half

Paronychia canadensis (L.) Wood
Rare to infrequent north and southwest; frequent southeast

Paronychia fastigiata (Raf.) Fern.
Infrequent southeast and south central

Parthenium integrifolium L.
Infrequent to rare eastern half

Parthenocissus quinquefolia (L.) Planchon
Frequent northwest; rare north central; common elsewhere

Parthenocissus vitacea (Knerr) A. S. Hitchc.
Frequent to common throughout most of state

Paspalum setaceum Michx. var. ciliatifolium (Michx.) Vasey
Rare northern half; infrequent southern half

Paspalum setaceum Michx. var. muhlenbergii (Nash) D. Banks
Infrequent to rare southern half

Paspalum setaceum Michx. var. stramineum (Nash) D. Banks
Infrequent to rare southeastern half

Pastinaca sativa L.
Common throughout

Pedicularis canadensis L. [incl. var. dobbsii Fern.]
Infrequent to rare west; frequent to common elsewhere

Pedicularis lanceolata Michx.
Frequent to common northeastern quarter; rare northwest and southern half

Pediomelum argophyllum (Pursh) Grimes
Frequent to common western half; rare northeast

Pediomelum esculentum (Pursh) Rydb.
Frequent to common west, especially in Loess Hills; infrequent to rare north central and south central

Pellaea atropurpurea (L.) Link
Rare northeast and southeast: Allamakee County and Van Buren county

Pellaea glabella Mett. ex Kuhn
Rare central; common northeast

Peltandra virginico (L.) Schott
Rare west central, east central and southeast: Cedar County, Des Moines county and Greene county

Pennisetum petiolare (Hochst.) Chiov.
Rare central: Story county

Penstemon albidus Nutt.
Rare northwest: Lyon county, Plymouth county and Sioux county

Penstemon cobaea Nutt.
Rare southwest: Fremont county

Penstemon digitalis Nutt.
Frequent southeast; rare northeast, east central, south central and southwest

Penstemon gracilis Nutt.
Rare west central and northwest: Harrison county and Lyon county

Penstemon grandiflorus Nutt.
Frequent to common in Loess Hills and sandy areas of central and east

Penstemon pallidus Small
Frequent southeast; rare extreme east and south central

Penstemon tubiflorus Nutt.
Rare central, east central, southeast and south central: Clarke County, Iowa county, Jefferson county 1932, Linn county and Story county

Penthorum sedoides L.
Infrequent northwest; common elsewhere

Perilla frutescens (L.) Britton
Rare central, east central and southeast: Clinton County, Davis County 1940, Johnson county, Jones county 1948 and Story county

Petunia axillaris (Lam.) BSP.
Rare escape from cultivation

Phalaris arundinacea L.
Common throughout

Phalaris canariensis L.
Rare waif throughout, from birdseed

Philadelphus pubescens Loisel
Rare northeast: Dubuque county

Phleum pratense L.
Common throughout

Phlox bifida Beck
Rare eastern half

Phlox divaricata L. [incl. ssp. laphamii (Wood) Wherry]
Infrequent northwest; frequent to common elsewhere

Phlox maculata L.
Frequent northeast; infrequent north central; rare east central, and in south central: Warren county

Phlox paniculata L.
Infrequent to rare escape from cultivation throughout

Phlox pilosa L. [incl. ssp. fulgida (Wherry) Wherry]
Infrequent southeast; frequent to common elsewhere

Phlox subulata L.
Rare escape from cultivation

Phragmites australis (Cav.) Trin. ex Steudel
Common central and north central; infrequent to rare elsewhere

Phryma leptostachya L.
Frequent to common throughout

Phyla lanceolata (Michx.) Greene
Infrequent northwest and in Iowan Surface; frequent to common elsewhere

Physalis heterophylla Nees
Frequent to common throughout

Physalis ixocarpa Brotero ex Hornem.
Rare escape from cultivation

Physalis pubescens L.
Rare throughout

Physalis pubescens L. var. integrifolia (Dunal) Waterfall
Rare escape from cultivation

Physalis virginiana P. Miller [incl. var. subglabrata (Mack. & Bush) Waterfall; var. sonorae (Torrey) Waterfall]
Frequent to common throughout

Physocarpus opulifolius (L.) Maxim.
Frequent to infrequent east and south central; rare north central

Physostegia parviflora Nutt. ex Gray
Frequent to common northeastern half; infrequent southeast and southwest

Physostegia virginiana (L.) Bentham
Rare northwest; infrequent elsewhere

Phytolacca americana L.
Frequent southeast; infrequent south central; rare north central, northeast and southwest

Picris echiodes L.
Rare south central: Clarke County 1924

Pilea fontana (Lunell) Rydb.
Rare in lakes area and east

Pilea pumila (L.) Gray [incl. var. deamii (Lunell) Fern.]
Rare northwest; frequent to common elsewhere

Pinus strobus L.
Rare eastern half; frequent in Paleozoic Plateau

Plantago aristata Michx.
Common southern half; infrequent elsewhere

Plantago cor data Lam.
Rare east central: Scott county (an 1847 collection by Parry from northeastar Davenport)

Plantago indica L.
Rare southeast: Jefferson county 1933

Plantago lanceolata L.
Rare northeast; infrequent extreme east; frequent to common elsewhere; spreading rapidly

Plantago major L.
Common west; infrequent to rare elsewhere

Plantago patagonica Jacq.
Common west; infrequent elsewhere

Plantago rugelii Dene.
Common throughout

Plantago virginica L.
Frequent southeast; infrequent south central; rare southwest

Platanthera clavellata (Michx.) Luer
Rare east: Fayette county 1894, Linn county, and Muscatine county 1894

Platanthera flava (L.) Lindley var. herbiola (R. Br.) Luer
Rare north central and east

Platanthera hookeri (Torrey ex Gray) Lindley
Rare and local northeast

Platanthera hyperborea (L.) R. Br. var. huronensis (Nutt.) Luer
Rare central, northwest and northeast: Cherokee County, Clay County, Dickinson county, Emmet county, Howard county, Story county 1890 and Winneshiek county n.d. (pre-1900)

Platanthera lacera (Michx.) G. Don ex Sweet
Rare southeast: Des Moines county and Lee county 1929

Platanthera leucophaea (Nutt.) Lindley
Rare east: Black Hawk County 1894, Clayton County, Delaware County, Henry county 1843, Iowa county 1903, Johnson county, Linn county 1921 and Muscatine county 1908

Platanthera praeclara Sheviak & Bowles
Rare in scattered locations throughout

Platanthera psycodes (L.) Lindley
Rare and local northeast and southeast

Platanus occidentalis L.
Frequent to common southern half and east; rare in Paleozoic Plateau

Poa annua L.
Frequent to common throughout, though rarely collected

Poa arida Vasey
Rare northwest: Lyon county

Poa bulbosa L.
Rare central, northwest and southeast: Plymouth county, Muscatine county 1922 and Story county 1929

Poa chapmaniana Scribner
Rare east central and southeast: Johnson county 1889, Louisa county n.d. (pre-1900) and Wapello county 1899

Poa compressa L.
Common throughout

Poa languida A. S. Hitchc.
Rare central and east: Allamakee County, Scott county n.d. (pre-1900), Story county 1897 and Muscatine county

Poa nemoralis L.
Rare central and east central: Boone County, Scott county, Story county

Poa paludigena Fern. & Wieg.
Rare northeast: Allamakee County, Dubuque county and Winneshiek county

Poa palustris L.
Common in lakes area and in Paleozoic Plateau; infrequent to rare elsewhere

Poa pratensis L.
Common throughout

Poa sylvestris Gray
Rare southeastern half of state

Poa trivialis L.
Rare central and northeast: Allamakee County, Clayton County and Story county

Poa wolfii Scribner
Rare: scattered locations in eastern half

Podophyllum peltatum L.
Common eastern two-thirds

Polanisia dodecandra (L.) DC.
Frequent to common north central, southeast and south central; infrequent elsewhere

Polanisia dodecandra (L.) DC. ssp. trachysperma (T. & G.) litis
Common north central; frequent to infrequent elsewhere

Polanisia jamesii (T. & G.) Iltis
Rare east central and southeast: Cedar County, Jackson county and Muscatine county

Polemonium reptans L.
Common eastern half; infrequent to rare western half

Polygala cruciata L.
Rare northeast and southeast: Buchanan County and Muscatine county 1898

Polygala incarnata L.
Rare east and southwest

Polygala polygama Walter var. obtusata Chodat
Rare east: Allamakee County, Buchanan County, Clinton County, Jackson county, Linn county and Wapello county 1941

Polygala sanguinea L.
Frequent to infrequent eastern two-thirds

Polygala senega L. [incl. var. latifolia T. & G.]
Frequent in Iowan Surface; infrequent in Paleozoic Plateau; rare central and southeast

Polygala verticillata L. [incl. var. isocycla Fern.; var. sphenostachya Pennell; var. ambigua (Nutt.) Wood]
Frequent southwest; rare north central; infrequent elsewhere

Polygonatum biflorum (Walter) Ell.
Common throughout

Polygonatum pubescens (Willd.) Pursh
Rare northeast: Allamakee County and Winneshiek county

Polygonella articulata (L.) Meisner
Rare central and east: Allamakee County, Buchanan County, Clinton County, Hardin county 1902, Jackson county, Louisa county 1910, Muscatine county and Winneshiek county

Polygonum achoreum Blake
Frequent to common throughout

Polygonum amphibium L. var. emersum Michx.
Common north central, south central and southwest; infrequent northwest and east central; rare in Paleozoic Plateau

Polygonum amphibium L. var. stipulaceum (Coleman) Fern.
Common north central, south central, and in lakes area

Polygonum aviculare L.
Frequent to common throughout

Polygonum cespitosum Blume var. longisetum (DeBruyn) Stewart
Rare southwest: Mills county

Polygonum convolvulus L.
Frequent to common throughout

Polygonum cuspidatum Sieb. & Zucc.
Infrequent east; rare elsewhere

Polygonum douglasii Greene
Rare northeast: Allamakee County

Polygonum erectum L.
Infrequent to rare east

Polygonum hydropiper L.
Not reported from extreme northwest counties; frequent to common elsewhere

Polygonum hydropiperoides Michx.
Rare central, east central, southeast and south central

Polygonum lapathifolium L.
Common western half and in Paleozoic Plateau; frequent elsewhere

Polygonum orientale L.
Infrequent south and east

Polygonum pensylvanicum L. var. laevigatum Fern.
Common throughout

Polygonum persicaria L.
Infrequent to rare northeastern quarter; frequent to common elsewhere

Polygonum punctatum Ell. [incl. var. confertiflorum (Meisner) Fassett]
Rare northwest; frequent to common elsewhere

Polygonum ramosissimum Michx.
Common southwest; frequent north central; infrequent eastern half

Polygonum sagittatum L.
Frequent northeastern quarter; infrequent southeast and south central

Polygonum scandens L. [incl. var. cristatum (Engelm. & Gray) Gl.; var. dumetorum (L.) Gl.]
Common north central and southwest; frequent eastern half; rare northwest

Polygonum tenue Michx.
Frequent in Paleozoic Plateau; infrequent to rare elsewhere

Polygonum virginianum L.
Common north central and east central; infrequent northwest; frequent elsewh

Polymnia canadensis L.
Frequent extreme east; infrequent to rare remainder of eastern half

Polypodium virginianum L.
Absent southwest and south; rare to infrequent elsewhere

Polystichum acrostichoides (Michx.) Schott
Frequent southeast; rare northeast

Polytaenia nuttallii DC.
Infrequent northeast and south central; rare elsewhere

Pontederia cordata L.
Infrequent to rare throughout

Populus alba L.
Infrequent escape from cultivation throughout

Populus balsamifera L.
Rare escape from cultivation north

Populus deltoides Bartram ex Marsh, ssp. monilifera (Aiton) Eckenw.
Infrequent west

Populus deltoides Bartram ex Marsh.
Common throughout

Populus grandidentata Michx.
Frequent to common north central, northeast and east central; rare southeast

Populus nigra L. var. italica Moench
Occasionally persists from cultivation

Populus tremuloides Michx.
Frequent to common northern half; infrequent to frequent southern half

Populus X rouleauiana Boivin
Infrequent to rare eastern half

Portulaca grandiflora Hooker
Widely cultivation, rarely escapes, not persisting

Portulaca oleracea L.
Common throughout

Potamogeton amplifolius Tuckerman
Rare central, northwest, north central and southeast: Cerro Gordo County 1896, Dickinson county, Floyd county 1880's, Hancock county, Muscatine county 1894 and Tama county 1891

Potamogeton crispus L.
Rare and local, though spreading

Potamogeton diversifolius Raf.
Rare northeast, southeast and south central

Potamogeton epihydrus Raf.
Rare north central, northeast and southeast: Bremer County, Fayette county 1894, Muscatine county 1896 and Winnebago county 1896

Potamogeton foliosus Raf.
Frequent to common throughout

Potamogeton friesii Rupr.
Rare northwest, north central and south central

Potamogeton gramineus L.
Infrequent north central and in lakes area

Potamogeton illinoensis Morong
Frequent north central and in lakes area; rare southeast and southwest

Potamogeton natans L.
Infrequent north central and in lakes area; rare northeast and southeast

Potamogeton nodosus Poiret
Common in lakes area and north central; infrequent elsewhere

Potamogeton pectinatus L.
Common in lakes area; infrequent elsewhere

Potamogeton praelongus Wulfen
Rare northwest and north central: Cerro Gordo County 1896, Dickinson county and Emmet county 1895

Potamogeton pusillus L.
Frequent in lakes area and southeast; infrequent to rare south central and southwest

Potamogeton pusillus L. var. tenuissimus Mert. & Koch
Rare in lakes area, and in west central: Greene county

Potamogeton richardsonii (A. Benn.) Rydb.
Common in lakes area; rare remainder of northwest and in Paleozoic Plateau

Potamogeton spirillus Tuckerman
Rare north central and southeast: Hancock county 1896, Muscatine county 1896 and Winnebago county 1896

Potamogeton strictifolius A. Benn.
Rare north central and in lakes area, last collected in 1917

Potamogeton vaseyi Robbins
Rare north central, east central and south: Linn county, Louisa county, Lucas county, Ringgold county and Worth county

Potamogeton zosteriformis Fern.
Frequent north central and in lakes area; rare northeast, and in east central, southeast and southwest: Fremont county 1905, Linn county 1895, Louisa county and Muscatine county 1895

Potentilla anserina L.
Rare central, northwest and north central: Dickinson county, Emmet county, Hamilton county 1886, Hardin county ca. 1900 and Wright county 1904

Potentilla argentea L.
Rare central and east, and in northwest: Dickinson county and Emmet county 1930

Potentilla arguta Pursh
Rare northeast; frequent to infrequent elsewhere

Potentilla fruticosa L.
Rare northeast and east central: Allamakee County, Jackson county, Jones county and Winneshiek county

Potentilla intermedia L.
Rare northeast: Black Hawk County

Potentilla norvegica L.
Common throughout

Potentilla palustris (L.) Scop.
Rare in north part of Des Moines lobe, and in north central, northeast and east central: Black Hawk County, Bremer County, Buchanan County, Cerro Gordo County and Jones county

Potentilla paradoxa Nutt. ex T. & G.
Frequent in north part of Des Moines lobe; infrequent northwest; rare southwest

Potentilla pensylvanica L.
Rare northwest: Lyon county and O'Brien county

Potentilla recta L.
Frequent to infrequent throughout most of state

Potentilla rivalis Nutt. [incl. var. millegrana (Engelm.) S. Watson; var. pentandra (Engelm.) S. Watson]
Rare north and east

Potentilla simplex Michx. [incl. var. calvescens Fern.]
Common eastern half; infrequent to rare western half

Potentilla tridentata (Solander) Aiton
Rare northeast: Allamakee County and Winneshiek county

Prenanthes alba L.
Frequent to common throughout most of state; not reported from northwest

Prenanthes aspera Michx.
Frequent to infrequent west; rare elsewhere

Prenanthes racemosa Michx. [incl. ssp. multiflora Cronq.]
Frequent to common north central and in lakes area; infrequent to rare elsewhere

Primula mistassinica Michx.
Rare central: Hardin county 1921

Prionopsis ciliata Nutt.
Rare central and southeast: HAR and Muscatine county

Proboscidea louisianica (P. Miller) Thell.
Rare northwest, east central, southeast and south central: Dickinson county 1912, Emmet county 1883, Keokuk county 1897, Madison county 1910, Muscatine county 1884 and Scott county

Proserpinaca palustris L. [incl. var. creba Fern. & Griseb.]
Rare east central and southeast: Clinton County and Muscatine county

Prunella vulgaris L.
Rare west; occasional elsewhere

Prunella vulgaris L. var. lanceolata (Bartram) Fern.
Rare northwest; common elsewhere

Prunus americana Marsh.
Common throughout

Prunus besseyi Bailey
Rare northwest: Lyon county

Prunus hortulana Bailey
Rare southeast: Lee county and Van Buren county

Prunus mexicana S. Watson
Infrequent throughout

Prunus nigra Aiton
Rare central, northwest and northeast: Allamakee County, Boone County 1936, Clay County 1934, Clayton County and Winneshiek county

Prunus pensylvanica L. f.
Common in Paleozoic Plateau; frequent north central; rare in Iowan Surface and south central

Prunus persica (L.) Batsch
Rare escape from cultivation

Prunus pumila L.
Rare north and southeast: Allamakee County, Buchanan County, Cerro Gordo County 1946, Delaware County, Dickinson county 1928, Louisa county, Lyon county, Muscatine county and Winneshiek county

Prunus serotina Ehrh.
Frequent to common throughout

Prunus virginiana L.
Common throughout

Psoralidium batesii Rydb.
Rare to infrequent southern half and north central

Psoralidium lanceolatum (Pursh) Rydb.
Rare west: Harrison county, Monona county, Pottawattamie county, Sioux county and Woodbury county

Ptelea trifoliata L.
Frequent southeast and extreme east; rare north central

Pteridium aquilinum (L.) Kuhn var. latiusculum (Desv.) Underw. ex Heller
Common northeast to rare central and southeast

Puccinellia distans (L.) Pari.
Rare central: Hamilton county

Pulsatilla patens (L.) P. Miller ssp. multifida (Pritz.) Zamels
Common northwest; infrequent in Iowan Surface; rare in Paleozoic Plateau

Pycnanthemum pilosum Nutt.
Frequent southeast; rare northwest: Emmet county 1923

Pycnanthemum tenuifolium Schrader
Frequent to common southern half; infrequent to rare northern half

Pycnanthemum virginianum (L.) Dur. & Jackson
Common eastern two-thirds; infrequent to rare west

Pyrola asarifolia Michx.
Rare northeast: Allamakee County and Winneshiek county

Pyrola elliptica Nutt.
Common in northeastern quarter; infrequent east; formerly found in north central and southeast

Pyrola secunda L.
Rare northwest and northeast: Allamakee County, Delaware County, Emmet county 1928, Winneshiek county

Pyrrhopappus carolinianus (Walter) DC.
Rare east central, southeast and southwest: Jefferson county 1934, Page county and Scott county

Pyrus communis L.
Rare central, east central and southeast: Clinton County 1921, Dallas County, Des Moines county, Johnson County and Lee county

Quercus alba L.
Rare southwest; absent northwest; common elsewhere

Quercus bicolor Willd.
Infrequent to frequent eastern two-thirds

Quercus borealis Michx. f. var. maxima (Marsh.) Ashe
Rare northwest; frequent to common elsewhere

Quercus ellipsoidalis E. J. Hill
Frequent to common northeast; infrequent extreme e

Quercus imbricaria Michx.
Common in extreme southeast; infrequent in southern tier of counties

Quercus macrocarpa Michx.
Frequent to common throughout

Quercus marilandica Muench.
Rare southeast

Quercus muhlenbergii Engelm.
Common east and southwest; frequent southeast and south central; rare central

Quercus palustris Muench.
Common southeast; infrequent east; rare south central and southwest

Quercus prinoides Willd.
Rare south central and southwest

Quercus stellata Wang.
Rare southeast and south central: Appanoose County, Decatur County, Henry county 1941, Lee county and Van Buren county 1941

Quercus velutina Lam.
Common southeastern two-thirds; frequent central; rare northwest

Quercus X bebbiana Schneider
Rare southeast: Muscatine county 1895

Quercus X bushii Sarg.
Frequent southeast and south central

Quercus X deamii Trel.
Rare southeast: Des Moines county 1929

Quercus X exacta Trel.
Rare southeast: Des Moines county

Quercus X fernowii Trel.
Rare southeast: Lee county

Quercus X hawkinsii Sudw.
Rare south central: Appanoose County 1906

Quercus X leana Nutt.
Rare southeast: Des Moines county and Keokuk county

Quercus X paleolithicola Trel.
Rare southeast: Keokuk county

Quercus X schuettei Trel.
Rare northeast: Bremer County

Ranunculus abortivus L.
Common throughout

Ranunculus acris L.
Rare throughout

Ranunculus aquatilis L. var. capillaceus (Thuill.) DC.
Frequent in Paleozoic Plateau

Ranunculus circinatus Sibth. var. subrigidus (Drew) Benson
Rare northwest: Clay County 1936, and Lyon county 1899

Ranunculus cymbalaria Pursh
Frequent north central and in lakes area; infrequent to rare rest of western half

Ranunculus fascicularis Muhl. [incl. var. apricus (Greene) Fern.]
Common east central; frequent in northeast; rare central and southeast

Ranunculus flabellaris Raf.
Common in lakes area; infrequent central and extreme east; rare south central

Ranunculus gmelinii DC. var. hookeri (D. Don) Benson
Rare northwest: Dickinson county 1950

Ranunculus longirostris Godron
Common in lakes area; infrequent central, east and in Paleozoic Plateau; rare elsewhere

Ranunculus pensylvanicus L. f.
Common in lakes area; infrequent north central and northeast; rare southern half

Ranunculus recurvatus Poiret
Infrequent extreme east; not reported from northwest; rare elsewhere

Ranunculus repens L.
Rare central, east central and southeast: Des Moines county, Johnson county 1909, Scott county and Tama county

Ranunculus rhomboideus Goldie
Infrequent to rare north

Ranunculus sceleratus L.
Frequent in lakes area; infrequent to rare elsewhere

Ranunculus septentrionalis Poiret
Rare northwest; frequent to common elsewhere

Ranunculus testiculatus Crantz
Rare east central and southwest: Cass County and Johnson county

Raphanus raphanistrum L.
Rare throughout

Raphanus sativus L.
Rare escape from cultivation throughout

Ratibida columnifera (Nutt.) Wooton & Standiey
Common northwest; rare remainder of western half

Ratibida pinnata (Vent.) Barnh.
Frequent to common throughout most of state

Reseda luteola L.
Rare central, and in west central: Harrison county 1930, Ida county and Monona county 1931

Rhamnus alnifolia L'Her.
Rare in Paleozoic Plateau

Rhamnus cathartica L.
Frequent northern half; rare southeast

Rhamnus davurica Pallas
Rare northeast: Winneshiek county

Rhamnus frangula L.
Rare escape from cultivation

Rhamnus lanceolata Pursh [incl. var. glabrata Gl.]
Frequent to common southern half and extreme east; rare or absent elsewhere

Rhexia virginica L.
Rare east central and southeast: Cedar County, Clinton County and Muscatine county

Rhus aromatica Aiton [incl. var. serotina (Greene) Rehder; var. illinoensis (Greene) Rehder; var. arenaria (Greene) Fern.]
Common southeast; rare northeast

Rhus copallina L.
Rare southeast and south central: Davis County 1943, Madison county 1930 and Van Buren county 1940

Rhus glabra L.
Common throughout

Rhus typhina L.
Common in Paleozoic Plateau; rare remainder of northeast; frequent extreme east central

Rhynchospora capillacea Torrey
Rare north

Ribes americanum P. Miller
Frequent northeastern quarter; infrequent extreme east and northwest; rare elsewhere

Ribes cynosbati L.
Infrequent to rare northwest and southern half; frequent to common elsewhere

Ribes hirtellum Michx.
Rare southeast: Van Buren county

Ribes hudsonianum Richardson
Rare northeast: Allamakee County, Clayton County, Delaware County and Dubuque county

Ribes missouriense Nutt. ex T. & G.
Common throughout

Ribes odoratum Wendl.
Rare west and south central

Ribes sativum (Reichenb.) Syme
Rare escape from cultivation

Robinia pseudoacacia L.
Frequent to common throughout most of state; often escaping from cultivation

Rorippa austriaca (Crantz) Besser
Rare central and west: Emmet county 1932, Ida county, Page county and Story county

Rorippa palustris (L.) Besser [incl. ssp. fernaldiana (Butters & Abbe) Jonsell; ssp. glabra (Schulz) R. Stuckey; ssp. hispida (Desv.) Jonsell]
Infrequent to common throughout

Rorippa prostrata (Bergeret) Schintz & Thell.
Rare northwest: Emmet county

Rorippa sessiliflora (Nutt.) A. S. Hitchc.
Frequent to infrequent throughout most of state; rare in Paleozoic Plateau

Rorippa sinuata (Nutt.) A. S. Hitchc.
Rare west, and in northeast, southeast and south central: Black Hawk County 1929, Fremont county 1888, Harrison county 1907, Henry county 1928, Lyon county, Marion county 1898,and Page county

Rorippa sylvestris (L.) Besser
Rare throughout most of state; absent northwest and south central

Rosa acicularis Lindley [incl. ssp. sayi (Schwein.) W. H. Lewis]
Rare northeast: Allamakee County, Clayton County, Delaware County and Winneshiek county

Rosa arkansana Porter var. suffulta (Greene) Cockerell
Infrequent to frequent throughout

Rosa blanda Aiton
Infrequent to frequent throughout

Rosa Carolina L. [incl. var. grandiflora (Baker) Rehder; var. villosa (Best) Rehder]
Common eastern half; frequent north central; infrequent to rare elsewhere

Rosa eglanteria L.
Infrequent escape from cultivation in north central, in lakes area and southeast

Rosa multiflora Thunb. ex Murray
Frequent to common southern half; rare north

Rosa palustris Marsh.
Rare southwest: Taylor county

Rosa setigera Michx. [incl. var. tomentosa T. & G.]
Rare southwest and southeast

Rosa woodsii Lindley [incl. var. fendleri (Crepin) Rydb.]
Rare northern half

Rotala ramosior (L.) Koehne
Rare north, central and east

Rubus allegheniensis Porter ex Bailey [incl. R. ostryifolius Rydb. & R. pensilvanicus Poiret]
Common throughout

Rubus flagellaris Willd.
Infrequent to rare northern half

Rubus hispidus L.
Rare northeast: Black Hawk County

Rubus idaeus L.
Rare escape from cultivation in southwest, north central and extreme east

Rubus occidentalis L.
Common throughout

Rubus pubescens Raf.
Rare northeast

Rubus strigosus Michx.
Infrequent northeast, except common in Paleozoic Plateau

Rudbeckia hirta L. [incl. var. pulcherrima Farw.]
Common throughout most of state; rare northwest

Rudbeckia laciniata L.
Common north central and in Paleozoic Plateau; frequent to infrequent elsewhere

Rudbeckia subtomentosa Pursh
Apparently absent west central and northwest; rare to infrequent elsewhere

Rudbeckia triloba L.
Frequent to common eastern two-thirds; infrequent southwest

Ruellia humilis Nutt. [incl. var. frondosa Fern.; var. longiflora (Gray) Fern.; var. expansa Fern.]
Frequent to common southern half; infrequent to rare northern half

Ruellia strepens L.
Infrequent to rare southern half

Rumex acetosella L.
Infrequent south central; frequent to common elsewhere

Rumex altissimus Wood
Infrequent in Paleozoic Plateau; frequent to common elsewhere

Rumex crispus L.
Infrequent south central and southwest; frequent to common elsewhere

Rumex maritimus L. var. fueginus (Phil.) Dusen
Frequent north central and in lakes area; rare elsewhere

Rumex mexicanus Meisner
Not reported southwest; infrequent to rare elsewhere

Rumex obtusifolius L.
Infrequent to rare throughout

Rumex occidentalis S. Watson
Rare northeast: Allamakee County

Rumex orbiculatus Gray
Infrequent to rare throughout

Rumex patientia L.
Infrequent north and east

Rumex venosus Pursh
Rare northeast and southeast: Des Moines county, Dubuque county 1936

Rumex verticillatus L.
Frequent eastern half

Ruppia maritima L.
Rare northwest: Dickinson county

Sabatia campestris Nutt.
Rare east central and southeast: Jackson county 1924 and Lee county 1931

Sagittaria brevirostra Mack. & Bush
Rare to infrequent eastern half; infrequent to common western half

Sagittaria calycina Engelm.
Infrequent southwestern two-thirds

Sagittaria cristata Engelm.
Rare southeastern two-thirds; frequent in lakes area

Sagittaria cuneata Sheldon
Rare northern half except frequent in lakes area

Sagittaria graminea Michx.
Rare southeastern two-thirds; frequent in lakes area

Sagittaria latifolia Willd. [incl. var. obtusa (Engelm.) Wiegand]
Common northeastern half; rare to infrequent elsewhere

Sagittaria rigida Pursh
Apparently absent from northwest, southwest and extreme northeast; infrequent elsewhere

Salix alba L.
Infrequent to rare escape from cultivation throughout

Salix amygdaloides Andersson
Frequent northeastern quarter; common elsewhere

Salix babylonica L.
Rarely persists from cultivation

Salix bebbiana Sarg.
Infrequent northeastern quarter; rare north central and extreme e

Salix Candida Fluegge ex Willd.
Rare northeastern third

Salix discolor Muhl.
Common north central and northeast; infrequent to rare elsewhere

Salix exigua Nutt. ssp. interior (Rowlee) Cronq.
Common throughout

Salix fragilis L.
Infrequent to frequent escape from cultivation throughout

Salix humilis Marsh, [incl. var. hyporhysa Fern.; var. microphylla (Andersson) Fern.]
Frequent to common throughout

Salix lucida Muhl.
Rare north

Salix nigra Marsh.
Infrequent northwest and extreme east; common elsewhere

Salix pedicellaris Pursh
Rare north central and northeast

Salix pentandra L.
Rarely persists from cultivation

Salix petiolaris Smith
Common north central and northeast; rare east central and southeast

Salix purpurea L.
Rare escape from cultivation

Salix rigida Muhl. [incl. var. angustata (Pursh) Fern.; var. watsonii (Bebb) Cronq.; var. vestita Andersson]
Frequent to common throughout

Salix sericea Marsh.
Rare e

Salix X subsericea (Andersson) Schneider
Rare northwest: Emmet county

Salsola collina Pallas
Rare central: Story county

Salsola iberica Sennen & Pau
Common north central and extreme west; rare to infrequent elsewhere

Salvia nemorosa L.
Rare west central and northwest: Dickinson county, Emmet county and Guthrie county

Salvia pitcheri Torrey ex Bentham
Rare west and east central: Clay County, Fremont county, Harrison county and Linn county

Salvia reflexa Hornem.
Frequent to common western half; infrequent to rare southeastern quarter

Salvia sylvestris L.
Rare northwest: Dickinson county 1920

Sambucus canadensis L.
Common throughout

Sambucus racemosa L. ssp. pubens (Michx.) House
Rare northeast and east central

Sanguinaria canadensis L.
Frequent to common throughout

Sanguisorba annua (Nutt. ex Hooker) T. & G.
Rare escape from cultivation

Sanicula canadensis L.
Frequent to common throughout

Sanicula gregaria Bickn.
Infrequent northwest; common elsewhere

Sanicula marilandica L.
Common in Paleozoic Plateau and southeast; infrequent to rare northern half

Sanicula trifoliata Bickn.
Common in Paleozoic Plateau; absent elsewhere

Saponaria officinalis L.
Frequent to common throughout

Sassafras albidum (Nutt.) Nees
Rare southeast: a single station in Lee county

Satureja vulgaris (L.) Fritsch
Rare northeast and east central: Allamakee County and Johnson county 1907

Saxifraga forbesii Vasey
Frequent in Paleozoic Plateau

Saxifraga pensylvanica L.
Frequent northeastern quarter; rare southeast and south central: Marion county and Muscatine county

Schedonnardus paniculatus (Nutt.) Trel.
Rare west: Guthrie county 1928, Harrison county, Lyon county, Page county, Plymouth county and Woodbury county

Scheuchzeria palustris L. var. americana Fern.
Rare northwest: Emmet county 1884

Schizachne purpurascens (Torrey) Swallen
Frequent in Paleozoic Plateau; rare elsewhere

Schizachyrium scoparium (Michx.) Nash
Common throughout

Schrankia nuttallii (DC. ex Britton & Rose) Standiey
Rare central, west central and southwest: Harrison county 1926, Mills county, Tama county 1895

Scirpus acutus Muhl. ex Bigelow
Frequent to common throughout most of state; rare northeast

Scirpus americanus Pers.
Frequent north central; rare northwest; rare to infrequent southwestern half

Scirpus atrovirens Willd.
Common throughout

Scirpus cyperinus (L.) Kunth [incl. var. brachypodus (Fern.) Gilly; var. rubricosus (Kunth) Gilly; var. laxus (Gray) Beetle]
Frequent to common northeast; infrequent to rare south

Scirpus fluviatilis (Torrey) Gray
Frequent to infrequent throughout most of state

Scirpus hallii Gray
Rare southeast: Louisa county and Muscatine county 1890

Scirpus heterochaetus Chase
Infrequent to rare throughout most of state

Scirpus maritimus L.
Rare northwest: Dickinson county and Palo Alto county 1943

Scirpus mucronatus L.
Rare southwest: Page county

Scirpus pallidus (Britton) Fern.
Infrequent western half

Scirpus pedicellatus Fern.
Rare east: Muscatine county, Scott county and Winneshiek county 1933

Scirpus pendulus Muhl.
Frequent to infrequent north central and south; rare northeast

Scirpus smithii Gray
Rare north central and northeast: Cerro Gordo County and Delaware County

Scirpus torreyi Olney
Rare east central: Clinton County 1878

Scirpus validus Vahl var. creber Fern.
Frequent to common throughout most of state

Scleria triglomerata Michx.
Infrequent to rare eastern half and southwest

Scleria verticillata Muhl. ex Willd.
Rare central, northwest and northeast: Chickasaw County, Clay County, Emmet county, Fayette county and Grundy county

Sclerochloa dura (L.) Beauv.
Rare southwest: Page county

Scolochloa festucacea (Wilid.) Link
Frequent in lakes area; rare north central

Scrophularia lanceolata Pursh
Frequent to common north and eastxtreme east; infrequent to rare elsewhere

Scrophularia marilandica L.
Infrequent northwest; frequent to common elsewhere

Scutellaria galericulata L.
Common in lakes area; infrequent to rare elsewhere

Scutellaria incana Biehler
Rare southeast: Louisa county 1892

Scutellaria lateriflora L.
Common northeastern two-thirds; frequent south central and southwest; rare northwest

Scutellaria leonardii Epling
Infrequent to frequent throughout

Scutellaria nervosa Pursh [incl. var. calvifolia Fern.]
Rare east central and southeast: Jefferson county 1930 and Linn county

Scutellaria ovata Hill [incl. var. versicolor (Nutt.) Fern.]
Frequent southeast; infrequent to rare northeast, east central and in Paleozoic Plateau

Scutellaria parvula Michx.
Common in Paleozoic Plateau; infrequent northwest; frequent elsewhere

Secale cereale L.
Infrequent escape from cultivation throughout

Sedum acre L.
Rare northeast: Dubuque county

Sedum ternatum Michx.
Rare east central: Cedar County 1950

Selaginella eclipes Buck
Rare southeast: Muscatine county and Worth county

Selaginella rupestris (L.) Spring
Rare extreme northwest, northeast and southeast

Senecio aureus L.
Frequent north central and in Paleozoic Plateau; rare elsewhere

Senecio congestus (R. Br.) DC.
Rare north central, northeast and in lakes area

Senecio glabellus Poiret
Rare southwest: Fremont county

Senecio integerrimus Nutt.
Rare north central and in lakes area

Senecio pauperculus Michx.
Frequent north central and southeast; rare northeast

Senecio plattensis Nutt.
Infrequent southwest; frequent to common elsewhere

Senecio pseudaureus Rydb. var. semicordatus (Mack. & Bush) T. Barkley
Rare central, west central and north: Clay County 1936, Dickinson county 1949, Emmet county 1882, Hancock county, Monona county, Story county 1907, and Winneshiek county

Senecio vulgaris L.
Rare central: Boone County

Setaria faberi Herrm.
Infrequent northern half; common southern half

Setaria geniculata (Lam.) Beauv.
Rare east central: Jones county

Setaria glauca (L.) Beauv.
Common throughout

Setaria italica (L.) Beauv.
Rare throughout

Setaria verticillata (L.) Beauv.
Rare northeast; infrequent to frequent elsewh

Setaria viridis (L.) Beauv.
Common throughout

Shepherdia argentea (Pursh) Nutt.
Rare west central and northwest: Emmet county, Harrison county, Monona county, Plymouth county and Woodbury county

Sibara virginica (L.) Roll.
Rare northeast: Winneshiek county

Sicyos angulatus L.
Frequent southeast and east; infrequent to rare western two-thirds of state

Sida spinosa L.
Infrequent to frequent southern half

Silene antirrhina L.
Infrequent to frequent north; frequent to common south

Silene cserei Baumg.
Rare eastern half; rare to infrequent northwest

Silene dichotoma Ehrh.
Frequent north central; rare southern half

Silene nivea (Nutt.) Otth
Infrequent in Paleozoic Plateau; rare elsewhere

Silene noctiflora L.
Infrequent escape from cultivation throughout; common in some areas

Silene pratensis (Rafn) Gren. & Godron
Infrequent south central and southwest; frequent to common elsewhere

Silene stellata (L.) Aiton f.
Common northwest and north central; frequent south; rare northeast

Silene virginica L.
Rare northeast and central: Black Hawk County 1949 and Boone County 1989

Silene vulgaris (Moench) Garcke
Frequent north central; rare south central

Silphium integrifolium Michx.
Frequent to common southern half; infrequent to rare northeastern quarter

Silphium laciniatum L.
Common western half; frequent to infrequent eastern half

Silphium perfoliatum L.
Frequent to common throughout most of state; infrequent northwest

Silphium terebinthinaceum Jacq.
Rare northeast and east central: Dubuque county and Jackson county

Sinapis alba L.
Rare central and northeast: Chickasaw County 1926 and Story county 1894

Sinapis arvensis L.
Common west; rare in Paleozoic Plateau; infrequent to frequent elsewhere

Sisymbrium altissimum L.
Frequent to common southern half; frequent north central; infrequent to rare elsewhere

Sisymbrium loeselii L.
Rare central and west: Emmet county 1925, Ida county, Monona county, Page county, Plymouth county, Story county and Woodbury county

Sisymbrium officinale (L.) Scop.
Frequent to common southern half; frequent to infrequent northern half

Sisyrinchium angustifolium P. Miller
Rare southern half

Sisyrinchium campestre Bickn. [incl. var. kansanum Bickn.]
Common throughout

Sium suave Walter
Common in lakes area; frequent to infrequent southern half; rare elsewhere

Smilacina racemosa (L.) Desf.
Infrequent northwest; common elsewhere

Smilacina stellata (L.) Desf.
Infrequent northwest; common elsewhere

Smilax ecirrhata (Engelm. ex Kunth) S. Watson
Infrequent east; frequent to common elsewhere

Smilax herbacea L. [incl. var. lasioneura (Hooker) A. DC]
Frequent to common throughout

Smilax hispida Muhl.
Infrequent northwest; common elsewhere

Solatium americanum P. Miller
Common throughout

Solatium carolinense L.
Infrequent to rare northeast; common elsewhere

Solatium dulcamara L.
Infrequent south central; rare north central, extreme east and southeast; spreading throughout

Solatium interius Rydb.
Rare: Harrison county

Solatium rostratum Dunal
Frequent to common western half and southeast; infrequent to rare northeast

Solidago canadensis L. [incl. var. gilvocanescens Rydb.; var. hargeri Fern.; var. scabra (Muhl.) T. & G.]
Frequent to common throughout

Solidago flexicaulis L.
Not reported from northwest; infrequent in Iowan Surface; frequent to common elsewhere

Solidago gigantea Aiton [incl. var. serotina (Kuntze) Cronq.]
Frequent to common throughout

Solidago hispida Muhl. ex Willd.
Rare in Paleozoic Plateau and extreme east

Solidago missouriensis Nutt. [incl. var. fasciculate Holz.]
Common western two-thirds; infrequent to rare east

Solidago nemoralis Aiton [incl. var. longipetiolata (Mack. & Bush) Palmer & Steyerm.]
Frequent to common throughout most of state; infrequent northwest

Solidago patula Muhl. ex Willd.
Rare southeast: Muscatine county

Solidago ptarmicoides (Nees) Boivin
Absent south central; infrequent to rare elsewhere

Solidago riddellii Frank ex Riddell
Frequent north central and in lakes area; rare northeast, and in southeast: Muscatine county 1895

Solidago rigida L. [incl. var. humilis Porter]
Infrequent southeast; frequent to common elsewhere

Solidago sciaphila Steele
Frequent to common in Paleozoic Plateau; rare east central: Jackson county and Clinton County

Solidago speciosa Nutt. [incl. var. jejunifolia (Steele) Cronq.; var. rigidiuscula T. & G.]
Common north central; rare southeast; frequent to infrequent elsewhere

Solidago uliginosa Nutt.
Rare northeast: Allamakee County

Solidago ulmifolia Muhl. ex Willd.
Rare northwest; common elsewhere

Sonchus arvensis L. [incl. ssp. uliginosus (Bieb.) Nyman]
Rare eastern quater; infrequent elsewhere

Sonchus asper (L.) Hill
Infrequent to rare eastern quater; frequent to common elsewhere

Sonchus oleraceus L.
Frequent southern half, north central and in lakes area; rare extreme east

Sorbaria sorbifolia (L.) A. Br.
Rare escape from cultivation in northeast: Allamakee County

Sorbus aucuparia L.
Occasional escape from cultivation

Sorghastrum nutans (L.) Nash
Common throughout

Sorghum bicolor (L.) Moench
Rare escape from cultivation

Sorghum halepense (L.) Pers.
Rare escape from cultivation in extreme south

Sorghum sudanense (Piper) Stapf
Rare escape from cultivation

Sparganium americanum Nutt.
Infrequent southeast; rare northeast, south central and southwest

Sparganium androcladum (Engelm.) Morong
Rare east central and southeast: Johnson county, Muscatine county 1922

Sparganium chlorocarpum Rydb.
Infrequent north central and in lakes area

Sparganium eurycarpum Engelm.
Rare northeast; frequent to infrequent elsewhere

Spartina pectinata Link
Frequent to common throughout

Spermolepis inermis (Nutt.) Math. & Const.
Rare central, northeast and southeast: Dubuque county, Lee county, Marshall county 1929 and Muscatine county

Sphaeralcea coccinea (Nutt.) Rydb.
Rare west central, northwest and southwest: Harrison county, Plymouth county and Pottawattamie county

Sphenopholis obtusata (Michx.) Scribner
Frequent to common north central and south central; infrequent to rare elsewhere

Sphenopholis obtusata (Michx.) Scribner var. major (Torrey) K. S. Erdman
Common southeast; rare western quarter; infrequent to frequent elsewhere

Spiraea alba Du Roi
Frequent to common northeastern half; infrequent to rare elsewhere

Spiranthes cernua (L.) L. C. Rich.
Infrequent eastern two-thirds; rare west central: Harrison county and Woodbury county

Spiranthes lacera (Raf.) Raf.
Rare north central, east and south central

Spiranthes lucida (H. H. Eaton) Ames
Rare northeast: Allamakee County

Spiranthes magnicamporum Sheviak
Rare north central, northeast and south central: Allamakee County, Delaware County, Dubuque county, Floyd county and Marion county

Spiranthes ovalis Lindley
Rare central, east central, southeast and south central: Henry county, Jackson county, Linn county, Marion county, Muscatine county and Polk county

Spiranthes romanzoffiana Cham.
Rare northwest: Dickinson county and Emmet county

Spiranthes vernalis Engelm. & Gray
Rare west central and southwest: Fremont county 1915, Harrison county 1918, Monona county and Woodbury county

Spirodela polyrhiza (L.) Schleiden
Frequent to common throughout most of state

Sporobolus asper (Michx.) Kunth
Infrequent to rare northeast; frequent to common elsewhere

Sporobolus clandestinus (Biehler) A. S. Hitchc.
Rare southeast: Henry county 1935, Jefferson county 1935 and Muscatine county

Sporobolus cryptandrus (Torrey) Gray
Frequent to common throughout

Sporobolus heterolepis (Gray) Gray
Common north central and southwest; infrequent elsewhere

Sporobolus neglectus Nash
Frequent north central and southwest; infrequent to rare elsewhere

Sporobolus vaginiflorus (Torrey ex Gray) Wood [incl. var. inaequalis Fern.]
Frequent to infrequent throughout

Stachys aspera Michx.
Rare northeast, east central and south central: Clayton County, Johnson county and Mahaska county

Stachys palustris L. [incl. var. pilosa (Nutt.) Fern.; var. homotricha Fern.; var. phaneropoda Weath.]
Infrequent northwest; frequent to common elsewhere

Stachys tenuifolia Willd. [incl. var. hispida (Pursh) Fern.]
Common east; infrequent to rare elsewhere

Staphylea trifolia L.
Rare northwest and north central; frequent to common elsewhere

Stellaria graminea L.
Rare central, northwest and east: Allamakee County, Emmet county 1923, Hardin county, Jefferson county 1935, Johnson county, Louisa county and Poweshiek county

Stellaria longifolia Muhl. ex Willd.
Infrequent north central and south central; rare northeast and southeast

Stellaria media (L.) Vill.
Rare northeast; common elsewhere

Stipa comata Trin. & Rupr.
Rare west central and northwest: Harrison county, O'Brien county, Osceola county and Woodbury county

Stipa spartea Trin.
Frequent to common throughout

Stipa viridula Trin.
Rare northern two-thirds, possibly native only in north Loess Hills

Streptopus roseus Michx.
Rare northeast and east central: Allamakee County, Clayton County, Delaware County, Dubuque county, Fayette county, Jackson county and Winneshiek county

Strophostyles helvula (L.) Ell.
Common southeast and southwest; frequent to infrequent elsewhere

Strophostyles leiosperma (T. & G.) Piper
Frequent to common southern half; infrequent to rare northern half

Stylisma pickeringii (Torrey ex M. A. Curtis) Gray var. pattersonii (Fern. & Schub.) Myint
Rare southeast: Muscatine county

Sullivantia sullivantii (T. & G.) Britton
Rare northeast and east central: Allamakee County, Clayton County, Delaware County, Dubuque county, Fayette county, Jackson county, Jones county and Linn county

Symphoricarpos albus (L.) Blake
Rare northeast: native in Allamakee County, rare escape from cultivation elsewhere

Symphoricarpos occidentalis Hooker
Common northwest, north central and southwest; infrequent to rare elsewhere

Symphoricarpos orbiculatus Moench
Common south; rare to infrequent north

Symplocarpus foetidus (L.) Nutt.
Rare e

Syringa vulgaris L.
Frequent persists from cultivation

Taenidia integerrima (L.) Drude
Infrequent to rare throughout

Talinum parviflorum Nutt. ex T. & G.
Rare northwest: Lyon county

Talinum rugospermum Holz.
Rare northeast: Allamakee County

Tanacetum vulgare L.
Rare escape from cultivation

Taraxacum laevigatum (Willd.) DC.
Infrequent to frequent throughout

Taraxacum officinale Weber
Common throughout

Taxus canadensis Marsh.
Infrequent to frequent northeast and east; rare southeast

Tephrosia virginiana (L.) Pers.
Infrequent east; rare northwest and northeast

Teucrium canadense L. [incl. var. virginicum (L.) Eaton]
Frequent to common throughout

Teucrium canadense L. var. boreale (Bickn.) Shinners
Infrequent northwest; common elsewhere

Thalictrum dasycarpum Fischer & Ave-Lall.
Common throughout

Thalictrum dioicum L.
Frequent to common northern half; rare in Paleozoic Plateau and south central

Thalictrum revolutum DC.
Rare east central and southeast: Des Moines county, Johnson county 1913, Lee county and Scott county

Thalictrum thalictroides (L.) Eames & Boivin
Frequent to common throughout

Thaspium barbinode (Michx.) Nutt.
Frequent eastern half; rare northwestern quarter

Thelypteris hexagonoptera (Michx.) Weath.
Rare to infrequent east; rare central: Hardin county 1901

Thelypteris palustris Schott var. pubescens (Lawson) Fern.
Frequent northeast; infrequent central and southeast

Thelypteris phegopteris (L.) Slosson in Rydb.
Rare northeast and southeast: Allamakee County, Delaware County 1878, Jones county and Muscatine county 1897

Thlaspi arvense L.
Frequent to common throughout

Thuja occidentalis L.
Rare: scattered populations

Thymelaea passerina (L.) Cosson & Germ.
Rare west: Harrison county, Mills county, Monona county, Plymouth county, Pottawattamie county and Woodbury county

Tilia americana L. [incl. var. neglecta (Spach) Fosb.]
Common throughout

Tilia heterophylla Vent.
Widely cultivation

Tomanthera auriculata (Michx.) Raf.
Rare east and south central

Torilis arvensis (Hudson) Link
Infrequent throughout

Toxicodendron radicans (L.) Kuntze ssp. negundo (Greene) Gillis
Common throughout

Toxicodendron rydbergii (Small ex Rydb.) Greene
Frequent to common northern half

Tradescantia bracteata Small
Common western two-thirds; rare to frequent northeast; infrequent southeast

Tradescantia occidentalis (Britton) Smyth
Rare west central: Woodbury county

Tradescantia ohiensis Raf.
Rare northwest but absent in lakes area; frequent to common southeastern two-thirds

Tradescantia virginiana L.
Rare southeast and south central: Davis County 1939, Jefferson county 1935, Keokuk county 1897, Mahaska county 1938, Wapello county 1902 and Washington county

Tragopogon dubius Scop. [incl. ssp. major (Jacq.) Voll.]
Infrequent northeast; common elsewhere

Tragopogon porrifolius L.
Rare north central and southeast

Tragopogon pratensis L.
Rare northwest and northeast; infrequent elsewhere

Triadenum fraseri (Spach) Gl.
Rare north and east

Tribulis terrestris L.
Infrequent southern half; rare northwest: Emmet county, Plymouth county and Sioux county

Trichostema brachiatum L.
Common extreme east; infrequent to rare elsewhere

Trichostema dichotomum L.
Rare: Madison county 1917

Tridens flavus (L.) A. S. Hitchc.
Common southeast; infrequent to rare extreme south and along Missouri R.

Trifolium arvense L.
Rare throughout

Trifolium aureum Pollich
Rare east and southwest

Trifolium campestre Schreber
Frequent to common north central and south central; infrequent to rare eastern half

Trifolium dubium Sibth.
Rare east central and southeast: Cedar County, Jefferson county 1935 and Washington county

Trifolium hybridum L.
Frequent to common throughout

Trifolium incarnatum L.
Rare central, northeast and east central: Dallas County 1924, FA 1898 and Iowa county 1903

Trifolium pratense L.
Common throughout

Trifolium reflexum L.
Rare east central and south

Trifolium repens L.
Common throughout

Trifolium resupinatum L.
Rare southeast: Jefferson county 1935

Triglochin maritimum L.
Rare central and north

Triglochin palustris L.
Rare northwest and northeast: Chickasaw County, Clay County, Dickinson county, Emmet county, Osceola county and Palo Alto county 1948

Trillium cernuum L.
Infrequent north central and in Iowan Surface; rare southeast

Trillium flexipes Raf.
Common northeast; rare elsewhere

Trillium nivale Riddell
Rare eastern half; infrequent western half

Trillium recurvation Beck
Infrequent to rare east

Triodanis leptocarpa (Nutt.) Nieuw.
Rare: Page county

Triodanis perfoliata (L.) Nieuw.
Common southeast; infrequent to rare northwestern half

Triosteum aurantiacum Bickn. [incl. var. illinoense (Wieg.) Palmer & Steyerm.]
Infrequent to rare eastern half, except common northeast

Triosteum perfoliatum L.
Infrequent northwest; frequent to common elsewhere

Triphora trianthophora (SW.) Rydb.
Rare and local northeast and east central

Triplasis purpurea (Walter) Chapman
Frequent southeast and southwest; infrequent to rare northeast and extreme east

Tripsacum dactyloides (L.) L.
Infrequent south

Triticum aestivum L.
Rare escape from cultivation, not persisting

Typha angustifolia L.
Frequent throughout

Typha latifolia L.
Infrequent to frequent throughout

Typha X glauca Godron
Frequent to common throughout

Ulmus americana L.
Common throughout

Ulmus pumila L.
Frequent escape from plantings

Ulmus rubra Muhl.
Infrequent northwest; frequent to common elsewhere

Ulmus thomasii Sarg.
Infrequent to rare northern half, and in southeast and south central: Decatur County 1900, Lee county 1939, Mahaska county 1928 and Van Buren county 1940

Urtica dioica L. [incl. ssp. gracilis (Aiton) Selander]
Common throughout

Urtica urens L.
Rare west central and northeast: Allamakee County 1925 and Carroll County 1921

Utricularia gibba L.
Rare east central and southeast: Johnson county and Muscatine county 1878

Utricularia intermedia Hayne
Rare northwest: Clay County 1939 and Emmet county 1904

Utricularia minor L.
Rare northwest and north central: Cerro Gordo County, Dickinson county, Emmet county 1880 and Hancock county

Utricularia vulgaris L.
Frequent northwest and north central; infrequent to rare elsewhere

Uvularia grandiflora Small
Infrequent northwest and south central; common elsewhere

Uvularia sessilifolia L.
Rare north central, northeast and southeast

Vaccaria pyramidata Medicus
Infrequent southwest; rare north central

Vaccinium angustifolium Aiton
Rare northeast and east central: Allamakee County, Clayton County and Jones county

Vaccinium myrtilloides Michx.
Rare northeast: Allamakee County and Clayton County

Valeriana edulis Nutt. ex T. & G. ssp. ciliata (T. & G.) F. G. Meyer
Rare northeastern third

Valeriana officinalis L.
Rare escape from cultivation

Vallisneria americana Michx.
Frequent in Mississippi R.; rare north central and in lakes area

Veratrum woodii J. W. Robbins
Rare south

Verbascum blattaria L.
Frequent north central; infrequent southeast and south central; rare northwest

Verbascum lychnitis L.
Rare south central: Madison county 1917

Verbascum phlomoides L.
Rare east, and in central and west central: Polk county and Sac county

Verbascum thapsus L.
Common throughout

Verbena bracteata Lag. & Rodr.
Infrequent northeast; frequent to common elsewhere

Verbena canadensis (L.) Britton
Rare northeast and south central: Dubuque county, Lucas county and Warren county

Verbena hastata L.
Common throughout

Verbena simplex Lehm.
Frequent northeast and extreme east; infrequent southeast; rare central and northwest: Story county and Lyon county 1928

Verbena stricta Vent.
Common throughout

Verbena urticifolia L.
Frequent to common throughout

Verbena X blanchardi Moldenke
Rare northeast and southwest: Black Hawk County and Cass County

Verbena X deamii Moldenke
Rare northeast: Allamakee County

Verbena X engelmannii Moldenke
Rare southeast: Louisa county, Muscatine county and Van Buren county

Verbena X moechina Moldenke
Rare east: Black Hawk County 1930, Clinton County, Jones county and Muscatine county 1929

Verbena X rydbergii Moldenke
Rare northwest, northeast, southeast and south central: Black Hawk County, Decatur County, Dickinson county, Louisa county 1927 and Muscatine county

Verbesina alternifolia (L.) Britton
Common south central; frequent southeast; rare north central

Verbesina encelioides (Cav.) Bentham & Hooker f. ex Gray ssp. exauriculata (B. L. Robinson & Greenman) Coleman
Rare central, west central and northwest: Emmet county 1934, Harrison county 1942, Palo Alto county 1934 and Story county 1934

Vernonia baldwinii Torrey [incl. var. interior (Small) Schub.]
Frequent to common southern half; rare north central

Vernonia fasciculata Michx. [incl. ssp. corymbosa (Schwein. ex Keating) S. B. Jones]
Infrequent northwest and south central; frequent to common elsewhere

Vernonia gigantea (Walter) Trel. ex Branner & Cov.
Frequent to infrequent southwestern quarter

Vernonia missurica Raf.
Frequent southeast; rare northwest

Veronica agrestis L.
Rare northwest, and in southwest: Page county

Veronica americana (Raf.) Schwein. ex Bentham
Rare northeast and southeast: Allamakee County, Lee county n.d. (ca. 1887), Muscatine county pre-1900 and Winneshiek county

Veronica anagallis-aquatica L.
Rare north and eastast central

Veronica arvensis L.
Frequent to common southeast; frequent southwest; infrequent to rare elsewhere

Veronica catenata Pennell
Frequent in Des Moines lobe; rare or absent elsewh

Veronica officinalis L.
Rare east central: Clinton County

Veronica peregrina L. [incl. var. xalapensis (HBK.) St. John & Warren]
Rare northwest; frequent to common elsewhere

Veronica persica Poiret
Rare northwest and east: Chickasaw County 1926, Johnson county 1926, Sioux county and Van Buren county

Veronica scutellata L.
Rare east central: Clinton County

Veronica serpyllifolia L.
Infrequent east

Veronicastrum virginicum (L.) Farw.
Infrequent northwest; common elsewhere

Viburnum dentaturn L.
Infrequent southwestern quarter

Viburnum lentago L.
Frequent to infrequent southern half; rare northwest; common elsewhere

Viburnum molle Michx.
Rare southeast and southwest: Henry county, Jefferson county, Pottawattamie county and Van Buren county

Viburnum opulus L.
Rare escape from cultivation

Viburnum prunifolium L.
Rare central, east central, southeast and southwest: Jackson county, Johnson county, Lee county, Poweshiek county, Taylor county and Van Buren county

Viburnum rafinesquianum Schultes [incl. var. affine (Bush) House]
Common northeast; frequent southeast; infrequent to rare western half

Viburnum trilobum Marsh.
Frequent in Paleozoic Plateau

Vicia americana Muhl. ex Willd.
Frequent to common northern half; infrequent to rare southern half

Vicia americana Muhl. ex Willd. var. minor Hooker
Rare west

Vicia cracca L.
Rare northwest: Clay County 1945

Vicia sativa L.
Rare east central: Scott county

Vicia sativa L. var. nigra L.
Frequent in Paleozoic Plateau; rare remainder of northeast and north central

Vicia villosa Roth
Infrequent to rare throughout most of state

Vinca minor L.
Rare escape from cultivation

Viola adunca J. E. Sm.
Rare northeast: Allamakee County

Viola canadensis L. var. rugulosa (Greene) C. L. Hitchc.
Infrequent to rare throughout most of state

Viola incognita Brainerd
Rare northeast and southeast: Allamakee County, Muscatine county 1935 and Winneshiek county

Viola lanceolata L.
Rare east: Benton County, Buchanan County, Cedar County, Johnson county, Jones county, Linn county, Scott county and Muscatine county 1923

Viola macloskeyi Lloyd ssp. pollens (Banks ex DC.) M. S. Baker
Rare east, and in northwest: Dickinson county

Viola missouriensis Greene
Frequent extreme east; infrequent to rare in remainder of eastern half

Viola missouriensis Greene X V. sororia Willd.
Rare central, east central and southeast: Benton County, Boone County, Clinton County, Jefferson county 1933, Story county and Van Buren county

Viola nephrophylla Greene
Infrequent throughout much of state; rare north central and southwest

Viola nephrophylla Greene X V. sororia Willd.
Rare east central: Clinton County, Johnson county

Viola pedata L. [incl. var. lineariloba DC]
Common in Paleozoic Plateau; frequent southwest; infrequent elsewhere

Viola pedatifida G. Don
Common northwest and north central; frequent to infrequent elsewhere

Viola pratincola Greene
Infrequent northwest and extreme east; frequent to common elsewhere

Viola pratincola Greene X V. pedatifida G. Don
Rare central, west central, northwest and e

Viola pubescens Aiton
Absent northwest and north central; rare to infrequent elsewhere

Viola rafinesquii Greene
Rare central, southeast and south central

Viola renifolia Gray
Rare northeast: Allamakee County, Clayton County, Dubuque county and Winneshiek county

Viola sagittata Aiton
Rare to infrequent east and south central; rare northwest: Lyon county 1896

Viola sagittata Aiton X V. pedatifida G. Don
Rare east central and southeast: Johnson county and Muscatine county

Viola sororia Willd.
Common throughout

Viola striata Aiton
Rare southeast: Jefferson county and Van Buren county

Viola tricolor L.
Rare escape from cultivation

Viola viarum Pollard
Rare southern half

Viola X bernardii Greene
Rare central, north central, east and south central

Viola X napae House
Rare central and southeast: Story county 1946 and Muscatine county 1924

Viola X sublanceolata House
Rare east central and southeast: Jones county and Muscatine county 1935

Vitis aestivalis Michx. [incl. var. argentifolia (Munson) Fern.]
Rare east: Clayton County, Dubuque county, Fayette county, Jackson county, Jones county, Lee county and Louisa county

Vitis cinerea Engelm.
Rare s

Vitis riparia Michx.
Common throughout

Vitis vulpina L.
Rare central, southeast and south central: Decatur County 1942, Lee county, Mahaska county, Poweshiek county and Van Buren county

Wisteria frutescens (L.) Poiret
Rare escape from cultivation in central: Boone County and Hardin county

Wolffia columbiana Karsten
Common in lakes area; infrequent to rare elsewhere

Wolffia punctata Griseb.
Infrequent to rare northeastern half

Woodsia ilvensis (L.) R. Br.
Rare northeast: Allamakee County and Winneshiek county

Woodsia obtusa (Sprengel) Torrey
Infrequent to frequent east; rare central and south central

Woodsia oregana D. C. Eaton
Rare northwest and northeast: Allamakee County, Lyon county and Winneshiek county

X Agrohordeum macounii (Vasey) LePage
Frequent northwest; rare southwest

X Elyhordeum iowense Pohl
Rare central: Story county

X Elyhordeum montanense (Scribner) Bowden
Rare north central: Humboldt county 1896

Xanthium spinosum L.
Rare central: Story county and Dallas County

Xanthium strumarium L. [incl. var. canadensis (P. Miller) T. & G.; var. glabratum (DC.) Cronq.]
Frequent to common throughout

Xyris torta J. E. Sm.
Rare east: Benton County, Buchanan County, Cedar County, Fayette county 1894, Linn county and Muscatine county

Yucca glauca Nutt. ex Fraser
Frequent to common in Loess Hills

Zannichellia palustris L.
Frequent in lakes area; infrequent northeastern quarter; rare southeast: Muscatine county 1894

Zanthoxylum americanum P. Miller
Common throughout

Zea mays L.
Infrequent escape from cultivation, not persisting

Zigadenus elegans Pursh
Infrequent north

Zigadenus glaucus Nutt.
Rare northeast

Zizania aquatica L. [incl. var. angustifolia A. S. Hitchc; var. interior Fassett]
Rare: scattered in northern two-thirds

Zizia aptera (Gray) Fern.
Infrequent to rare northern half; not reported elsewhere

Zizia aptera (Gray) Fern. X Z. aurea (L.) Koch
Rare northwest and northeast: Delaware County and Emmet county

Zizia aurea (L.) Koch
Frequent to common throughout