Astragalus sect. Reventi-arrecti
Rev. N.-Amer. Astragalus, 158. 1923.
Herbs perennial, caulescent, stems shorter or longer than combined length of peduncles and racemes; caudex usually superficial, rarely slightly subterranean. Hairs basifixed or malpighian. Stems several to many. Stipules distinct. Leaves odd-pinnate, usually petiolate, rarely short-petiolate or subsessile; leaflets (5 or)7–41. Racemes loosely flowered, sometimes initially densely flowered, flowers usually ascending, spreading, or nodding, rarely declined; length of peduncle and raceme combined usually exceeding stem length, sometimes shorter. Calyx tubes short-cylindric or campanulate. Corollas whitish, greenish white, cream, ochroleucous, pink, or purple with pale wing apices, banner 40–90°, keel apex usually round or narrowly triangular, sometimes sharply deltate or beaklike. Legumes persistent, sessile or stipitate, usually erect or incurved-ascending, rarely deflexed, ovoid, oblong-ovoid to ellipsoid, or linear-oblong or -oblanceoloid, obcompressed or dorsiventrally or 3-sided compressed or subterete, unilocular or ± bilocular. Seeds 14–36.
Distribution
w United States, Mexico.
Discussion
Species 14 (12 in the flora).
Section Reventi-arrecti consists of six subsections with distribution in the Columbia and Great basins, eastward to southwestern Montana and northwestern Wyoming, southward to southern Nevada, Arizona, and western New Mexico, and in Baja California.
The subsections are: subsect. Reventi M. E. Jones (Astragalus adanus, A. reventus, A. sheldonii); subsect. Terminales Barneby (A. terminalis); subsect. Arrecti M. E. Jones (A. arrectus, A. riparius); subsect. Eremitici Barneby (A. atropubescens, A. eremiticus, A. remotus, A. scaphoides); subsect. Orcuttiani (Rydberg) Barneby (A. ackermanii); and subsect. Obscuri Barneby (A. obscurus).
Selected References
None.