2. Helianthemum canadense (L.) Michx.

Pl. 359 g–i; Map 1554

Stems 10–40 cm long. Leaves 4–30 mm long, those of the main stems longer than those of the branches, the upper surface appearing green, but sparsely to moderately stellate-hairy and sometimes also with a few simple hairs, the undersurface obscured by the dense stellate hairs. Petaliferous flowers 1(2) at each stem tip. Sepals of petaliferous flowers 5–9 mm long, with longer, simple hairs intermixed with the shorter, stellate ones; those of cleistogamous flowers 2–4 mm long, only stellate-hairy. Petals 8–15 mm long. Fruits maturing from petaliferous flowers 4–7 mm long, with numerous seeds; those developing from cleistogamous flowers 2–3 mm long, with 5–12 seeds. Seeds 1.0–1.5 mm long, the surface pebbled to finely tubercled. 2n=20. April–July.

Uncommon, known thus far only from Maries and Stoddard Counties (eastern U.S. west to Minnesota, Missouri, and Alabama; Canada). Ledges of sandstone bluffs and sand blowouts.

Steyermark (1963) excluded H. canadense from the flora based on the likelihood that the only specimen that he encountered attributed to this species (a vegetative collection from Barry County) could not be identified reliably to species. In the research toward their revision of the genus, Daoud and Wilbur (1965) annotated this specimen as H. bicknellii but instead cited one of Steyermark’s own collections (from Maries County) as confirmation that H. canadense is present in Missouri. Since then it has been collected only rarely in the state, presumably in part because plants of Lechea are so infrequently encountered with open flowers.