Actinomorphic: Flowers with radial symmetry with several to many planes through the flower giving mirror images; contrast to zygomorphic.
Acute: Forming an acute angle (less than 90°).
Alternate: Leaves or branches arranged so that only one arises at the same level (node) on the stem (see opposite and whorl).
Angle: Ridge (see Galium and Scutellaria).
Annual: Having one growth and flowering period, usually germinating in the spring and flowering and dying before fall.
Anther: Pollen-producing part of the stamen at the tip of the filament.
Appressed: Lying flat against another structure.
Auricles: Paired “ears” projecting sideways at the sheath-blade junction of grass leaves.
Awn: Wiry bristle sometimes attached to the tips of bracts (lemmas or glumes) surrounding grass florets.
Axil: The point where two parts meet, such as leaf and stem.
Basal: Located near the base of a structure, such as basal leaves located at the base of the stem.
Beak: Pointed projection on a fruit or seed.
Berry: Fleshy fruit with several seed chambers, e.g., tomato.
Biennial: Having two growth periods and then flowering; germinating and growing the first year, resuming growth the following spring, then flowering and dying that year.
Blade: The flattened portion of the leaf.
Bract: Small leaflike structures, usually associated with flowers in the inflorescence.
Bulb-based: Hairs with a swollen base.
Calyx: The collective sepals, the lower whorl of leaflike bracts at the base of the flower: Sometimes colored as in iris and lily.
Capsule: A dry fruit made up of several sections and opening by splitting from the top.
Catkin: An inflorescence type where reduced flowers (without sepals or petals) are closely bunched on an unbranched axis.
Chordate: Heart shaped.
Clasping: Structure partially surrounding another to which it is attached at the base.
Composite: A member of the daisy family (Asteraceae or Compositae).
Compound leaf: Leaf made up of three or more separate leaflets.
Conical: Cone shaped.
Corolla: The collective petals of the flower.
Corymb: Flat-topped inflorescence whose flowers or heads are on flower stalks of varying lengths, the outer flowers having longer flower stalks (see umbel).
Corymbiform: An inflorescence in the shape of a corymb.
Cyme: Inflorescence type with successive flowers arising from below earlier blooming flowers, the oldest flower in the center of the flower cluster.
Disk flowers: Central flowers in composite (daisy family) heads, having five-parted, tubular corollas rather than straplike petals of ray flowers.
Ears: In grasses, tiny appendages on either side at the base of the leaf blade (auricles).
Fen: Boglike area with continuous groundwater seepage, sometimes with hard water, and having a characteristic flora.
Fertile: Producing functional reproductive structures.
Filament: Stalk of the stamen that bears the anther.
Fillaries: Bracts surrounding the heads of composites (Asteraceae); also called involucral bracts.
Floral cup: A cup at the base of a flower with sepals, petals, and stamens attached at the margin.
Floral tube: Similar to a floral cup except the structure is more elongate.
Floret: Diminutive of flower, used to designate grass and sedge flowers.
Flower: Sexual reproductive structure consisting of ovary(s) or stamens or usually both and usually with surrounding petals and sepals producing fruits containing seeds.
Follicle: Dry fruit opening on one side; a milkweed pod is a follicle.
Frond: Leaf of a fern.
Fruit: Structure containing mature seeds; the ripened ovary; either dry as in milkweed pods or fleshy as in rose hips.
Fruiting: The process of fruit ripening, producing mature seeds.
Glandular: Areas where hairs or specialized cells secrete substances, such as glandular hairs secreting sticky materials or nectaries secreting nectar.
Glumes: Pairs of bracts attached at the base of grass spikelets, lower (first glume) attached just below and across from the upper (second glume).
Habitat: Type of environment within which an organism lives; examples are moist prairie and open woods.
Head: Tight cluster of flowers, round or elongate; especially in the daisy, pea, and mint families.
Hip: Fleshy, red growth surrounding the fruits (“seeds”) of roses.
Hood: On milkweed flowers, an upward extension of the petal forming a hoodlike structure.
Horn: On milkweed flowers, a curved petal appendage attached within the hood.
Inferior ovary: Ovary with the sepals, petals, and stamens attached at the top.
Inflorescence: Collective flower cluster.
Involucre: Whorl of bracts attached below a head of flowers, especially in the daisy family.
Leaf: Usually flat, green appendage attached to the stem consisting of leaf stalk (petiole) and blade or sheath and blade (in grasses and sedges).
Leaflet: Segment of a compound leaf (a leaf composed of individual leaflets).
Lemma: Larger of two bracts that surround the grass floret (see palea).
Ligule: Tiny membrane of tissue or row of hairs on the upper side at the junction of the blade and sheath of grass leaves.
Lobe: Outward growth, usually rounded.
Mesic: Soil neither excessively moist nor excessively dry.
Nectar guide: Colored dots within the corolla that apparently assist insects in locating nectar in flowers.
Nectary: Nectar-secreting structures, usually at the base of the petals.
Node: Portion of the stem from which leaves arise; often somewhat swollen.
Nutlet: Tiny hard fruit.
Opposite: Situation where two leaves or branches arise on opposite sides of the stem at a node, as in members of the mint family (see alternate and whorl).
Ovary: Expanded lower portion of the pistil where seeds will develop in the flower.
Ovate: Egg shaped; wider or thicker below the middle.
Palea: Membranous bract surrounding the grass floret, opposite and smaller than the lemma.
Palmate: Parts originating at a common point and radiating out.
Panicle: Inflorescence type that is highly branched with flowers at the tips of the branches.
Perennial: Producing growth and flowers year after year (see annual and biennial).
Perigynium: Tubular membrane (open at the top) that encloses the pistil in sedges.
Petal: White or colored lamina surrounding (or growing from the top of) the ovary in the flower. Sometimes sepals are also petallike (e.g., lily), and occasionally only one whorl is present (Anemone), then termed sepals.
Petiole: Stalk of a leaf, the portion connecting the leaf blade with the stem.
Pinnate: Having parts attached on both sides of a central axis.
Pioneer: opportunistic species that quickly invades into disturbed places.
Pistil: The female portion of the flower, in the center of the flower and containing the ovary where the seeds are produced.
Pod: generic name for dry fruits that open by splitting at one to several places; often used to designate pea family fruits.
Pollen: Male spores produced by the stamens.
Raceme: Unbranched inflorescence type with the flowers attached to the axis by short stalks.
Ray: Straplike “petals” surrounding composite (daisy family) heads, such as the rays (“petals”) on sunflower heads.
Ray flowers: Flowers of composites (daisy family) on the perimeter of heads (sunflower) or making up all the flowers of the head (false dandelion); sometimes lacking, as in blazing star (see disk flowers).
Receptacle: Top of the flower stalk to which the flower parts are attached.
Recurved: Bending backward upon itself.
Reflexed: Curving backward upon itself.
Reticulate: Netlike.
Rhizome: Horizontal underground stem, usually giving rise to new shoots.
Rosette: Cluster of leaves attached to a short stem in a whorled fashion.
Sepal: Outer (lower) leaflike bract at the base of the flower; usually green but occasionally white or colored (see calyx).
Sessile: Attached directly, without a stalk; a sessile leaf has no leaf stalk (petiole).
Sheath: Cylinder of tissue surrounding the stem or other plant part, especially prominent on sedges and grasses; in sedges and a few grasses the sheath edges grow together forming a cylinder, termed a “closed sheath.”
Spike: Inflorescence type with flowers sessile on an unbranched axis.
Spikelet: Cluster of one or more grass florets, subtended by two sterile bracts (glumes); in sedges consisting of floret with perigynium and single subtending bract.
Spindle-shaped: Widest at the middle and tapering to both ends.
Spore: Tiny reproductive structure of ferns and horsetails.
Spur: Elongate, hollow, curved growth, often containing a nectary.
Stamen: Male structure in the flower producing pollen; almost always more than one and frequently three, four, five, six, or ten to many per flower.
Sterile: Not producing reproductive structures.
Stigma: Upper portion of the pistil that captures pollen (see pistil, ovary, and style).
Stipule: Paired leaflike bracts at the base of the leaf, one on each side of the leaf stalk (petiole) at the junction with the stem.
Style: Stalk at the top of the ovary that carries the stigma at the upper end.
Tendril: Hairlike growth that winds around whatever it touches, usually substituting for a leaf or leaflet.
Terminal: Referring to the tip of a structure.
Umbel: Flat-topped inflorescence with flowers or flower clusters at the ends of stalks originating at the same point on the stem (see corymbiform).
Whorl: Leaves or branches arranged so that more than two leaves arise at the same level (node) on the stem (see alternate and opposite).
Zygomorphic: Flowers having bilateral symmetry, that is, having only one plane through the flower, which produces mirror images; contrast to flowers with radial symmetry (actinomorphic) with several to many planes giving mirror images.