Cistaceae
Rockrose Family
Helianthemum bicknellii Fern.
- Stem: perennial; 6” to 1 1/2’ tall; numerous short branches toward the top; hairy; lower leaves often drop, upper leaves very crowded.
- Leaves: alternate; oblong, widest above the middle, tapering bases and rounded tips; lower, 1” by 1/4”, upper, 1/2” by 1/8”; sessile; short hairs above and below.
- Inflorescence: first flowers in a terminal raceme and with petals, later flowers in clusters in the leaf axils and without petals.
- Flowers: petals yellow, 1/2” long, triangular; sepals hairy; many stamens; flowering from mid-June to early July; later flowers develop without petals.
- Fruits: tiny capsules 1/16” in diameter, within the calyx; fruiting begins in early July.
- Habitat: frequent on sandy or rocky prairies.
- Notes: Another frost weed, Helianthemum canadense (L.) Michx., barely enters Iowa. It is very similar to H. bicknellii except the outer two sepals are shorter than the inner three on the flowers bearing petals. In H. bicknellii, all the sepals are the same height. H. canadense is rare in northeast Iowa.
- Bibliography from Biodiversity Heritage Library
- Vascular Plants of Iowa
