Platystemon

Bentham
Trans. Hort Soc. London, ser. 2, 1: 405. 1834.
Common names: Cream cups
Etymology: Greek platus, broad, and stemon, stamen
Treatment appears in FNA Volume 3.

Herbs, annual, caulescent, usually distinctly pubescent, from fibrous roots. Stems leafy, erect to decumbent, branching distally. Leaves mostly opposite or whorled, sessile; blade broadly linear, unlobed. Inflorescences axillary or terminal, 1-flowerd; bracts absent; bud nodding. Flowers: receptacle slightly expanded beneath calyx; sepals 3, with overlapping, loosely connivent flaps; petals 6, occasionally more on robust specimens; stamens many in several series; filaments dilated distally; pistil 6-many-carpellate; ovary with each carpel forming almost closed locule with 4-24 ovules; stigmas 1 per carpel. Capsules erect or sometimes nodding, carpels dissociating, each torulose and breaking transversely into 1-seeded segments, sometimes also releasing free seeds. Seeds usually many, aril absent. x = 6.

Distribution

w United States

Discussion

Species 1 (1 in the flora).