Proc. Linn. Soc. London 1: 48. 1839
Herbs, from slender, knotty rhizomes with fibrous roots, generally pubescent throughout. Stems branched distally, with 2–5 papery bracts sheathing proximally. Leaves sessile or subsessile; blade broadly ovate to oblanceolate, veinlets forming loose reticulum. Inflorescences strictly terminal. Flowers 1–4(–7) in a cluster, nodding, pedicellate; tepals deciduous, distinct, weakly gibbous proximally; stamens hypogynous, basally adnate to tepals; filaments filiform to basally dilated; anthers linear-oblong, extrorse; ovary superior, sessile, 3-locular, narrowly ellipsoid to obovoid, ovules 2–6 per locule, pendulous or horizontal; style included or exserted, filiform; stigma not lobed or weakly 3-lobed; pedicel slender. Fruits baccate, straw-colored to red, ± fleshy. Seeds light yellow to orangish brown, ellipsoid to oblong, smooth. x = 6, 8, 9, 11.
Species 5 (5 in the flora).
The American species have long been treated as section Prosartes of the otherwise Asian genus Disporum (H. Hara 1988; Q. Jones 1951). However, cytological, morphological, and molecular evidence indicates a degree of difference that justifies generic status for this group (M. N. Tamura et al. 1992; Z. K. Shinwari et al. 1994; T. Fukuhara and Z. K. Shinwari 1994). Within Prosartes there are two disjunct, east-west pairs: P. lanuginosa and P. hookeri, and P. trachycarpa and P. maculata (F. H. Utech et al. 1995; C. E. Wood Jr. 1970).
|1||Ovary broadly ovoid to obovoid or obconic to obpyriform, becoming 3-lobed after anthesis, papillose, sometimes also with ascending, stellate glandular hairs; ovules horizontal; leaf margins moderately pubescent, hairs scattered, flattened.||> 2|
|1||Ovary ellipsoid or ovoid to obovoid, glabrous or somewhat pubescent; ovules pendulous; leaf margins glabrous or short-pubescent.||> 3|
|2||Leaf apex acute, with 7–9 prominent veins; tepals lacking purple spots and basal claws, 8–15 mm; ovary finely papillose; berries reddish orange to bright red; cordilleran and interior North America.||Prosartes trachycarpa|
|2||Leaf apex acuminate, with (3–)5 prominent veins; tepals spotted with purple, narrowly clawed basally, 15–25 mm; ovary papillose with stellate glandular hairs; berries pale straw-colored; e North America.||Prosartes maculata|
|3||Stems freely branched; leaf margins glabrous or sparsely pubescent; perianth cylindrical, truncate basally; tepals 15–28 mm; berries 3–6-seeded; coastal w North America.||Prosartes smithii|
|3||Stems sparingly branched; leaf margins short-pubescent, hairs pointed sharply forward; perianth turbinate, narrowed basally; tepals 8–22 mm; berries 1–4(–6)-seeded; e, w North America.||> 4|
|4||Tepals greenish yellow, linear-lanceolate, apex long-acuminate; ovary glabrous; stigma weakly 3-lobed; abaxial leaf surface lanulose, densely so on veins; e North America.||Prosartes lanuginosa|
|4||Tepals creamy white, oblanceolate, apex short-acuminate; ovary glabrous or somewhat pubescent; stigma unlobed or rarely 3-lobed; abaxial leaf surface scabrous or puberulent, especially on veins; w North America.||Prosartes hookeri|