Ihsan A. Al-Shehbaz
Tribe: Thelypodieae Prantl in Engler & Prantl, Nat. Pflanzenfam. III. 2: 155. 1891.
Type species: Thelypodium laciniatum (W. J. Hooker) Endlicher (based on Macropodium laciniatum W. J. Hooker).
Pachypodium Nuttall in Torrey & A. Gray, Fl. N. Am. 1: 96. 1838, nom. illeg.; not Pachypodium Lindley, Dewards’s Bot. Reg. 16: t. 1321.1830; nor Pachypodium Webb & Berthelot, Hist. Nat. Iles Canaries (Phytogr.). 3(2.1): 74. 1836, nom. illeg. Type species: P. laciniatum (W. J. Hooker) Nuttall (based on Macropodium laciniatum W. J. Hooker).
Pleurophragma Rydberg, Bull. Torrey Bot. Club 34: 433. 1907. Type species: P. integifolium (Nuttall) Rydberg (based on Pachypodium integrifolium Nuttall).
Stanleyella Rydberg, Bull. Torrey Bot. Club 34: 435. 1907. Type species: S. wrightii (A. Gray) Rydberg (based on Thelypodium wrightii A. Gray).
Herbs, biennial, rarely annual or perennial with caudex. Trichomes absent or simple. Multicellular glands absent. Stems erect or ascending, sometimes decumbent, 1 to several from base, branched basally and/or apically, glabrous or pubescent. Basal leaves rosulate or not, simple, petiolate, entire, dentate, laciniate, lyrate or pinnately lobed, glabrous or pubescent; cauline leaves petiolate or sessile, base cuneate, attenuate, auriculate, or sagittate, margin entire, dentate, or pinnately lobed. Racemes ebracteate, corymbose or lax, slightly to considerably elongated in fruit; rachis straight; fruiting pedicels glabrous, erect to ascending or divaricate, very rarely reflexed, flattened or not at base. Sepals ovate to oblong or linear, free, deciduous, erect to ascending or spreading to reflexed, equal, base of lateral pair slightly saccate or not. Petals white or lavender to purple, erect or spreading, longer than sepals; blade spatulate to obovate or oblanceolate to linear, obtuse at apex, crisped or not; claw not or differentiated from blade, glabrous, unappendaged, entire. Stamens 6, exserted or included, erect to spreading, subequal or tetradynamous; filaments wingless, unappendages, glabrous, free or median ones rarely united; anthers linear or rarely oblong or ovate, not apiculate, often circinately coiled after dehiscence. Nectar glands confluent and subtending bases of all filaments, or 2 or 4 and lateral. Ovules 12–128 per ovary; placentation parietal. Fruit dehiscent capsular siliques, linear, terete or slightly latiseptate, not inflated, unsegmented; valves not thickened, with a distinct midvein, glabrous, not keeled, often torulose, wingless, unappendages; gynophore often distinct, 0.5–8.5 mm; replum rounded; septum complete, membranous, not veined; style distinct, 0.2–5 mm, cylindrical or rarely subclavate or subconical; stigma capitate, entire. Seeds uniseriate, wingless, oblong to rarely ovate, plump or flattened; seed coat minutely reticulate, not mucilaginous when wetted; cotyledons oblique, rarely incumbent or accumbent; n = 13.
Species 16. W United States, sw Canada, n Mexico.
References: Al-Shehbaz (1973), Payson (1923).
See interactive key to the species