290 LEGUMINOSAE (PEA FAMILY) 



nent, 10-15 mm. long, pendulous, glabrous, cuspidate. Colorado to Nebraska 

 and far northward. 



54. Astragalus Grayi Parry, Wats. Am. Nat. 8: 212. 1873. Distinguished 

 from the last by the broader leaflets, quite strongly veined, and by the some- 

 what thinner ascending pod: flowers light yellow. Through the western half 

 of Wyoming. 



55. Astragalus flaviflorus (OK.) Sheld. 1. c. 158. Canescent with appressed 

 I hairs; diffusely branched and decumbent: leaflets 5-11, oblong or lanceolate- 

 ,' linear, subacute, glabrate above: peduncles longer than the leaves; spikes 



becoming elongated and loose: the subulate calyx-teeth nearly as long as the 

 campanulate tube: corolla yellow: pod short, mostly included in the calyx, 

 strongly obcompressed and with a broad furrow below. A. flavus. Western 

 Wyoming and Colorado and westward. 



56. Astragalus gracilis Nutt. Gen. 2: 100. 1818. Subcinereous; stems 

 slender, virgate, 2-4 dm. high: leaflets 11-17, linear or filiform: racemes dense, 

 elongated, long-peduncled ; flowers pale purple or whitish: pods spreading, 

 coriaceous, elliptic-ovate, strongly concave dorsally, white-hairy or at length 

 glabrous, transversely rugose-veined, wholly 1-celled, the ventral suture 

 thick and prominent, 4-5 mm. long. Extending from the mountains east to 

 the Missouri. 



57. Astragalus microlobus Gray, Proc. Am. Acad. 6: 203. 1866. Closely 

 allied to the foregoing but the stems diffuse : leaflets shorter, linear or oblong- 

 linear: racemes rather short and usually loosely flowered; flowers deep purple: 

 pods reflexed, thick-cartilaginous, puberulent, finely rugulose, a little flat- 

 tened on the back, the ventral suture very thick. Same range as the pre- 

 ceding. 



58. Astragalus viridis (Nutt.) Sheld. 1. c. 118. Caulescent but depressed- 

 spreading, intricately branched from a long root, hoary with a short silky 

 pubescence: leaflets 5-7, linear-subulate, usually rigid am} divaricate, pungent: 

 flowers 1-3, sessile in the axils of the leaves, ochroleucous or tinged with 

 violet: pods ovate, sessile, compressed, pubescent, acuminate, somewhat in- 

 curved, usually 1-seeded. A. Kentrophyta. (A. viridis impensa Sheld. 1. c.) 

 New Mexico to Canada and west to Nevada. 



59. Astragalus aculeatus A. Nels. Bull Torr. Bot. Club 26: 10. 1899. 

 Very similar to the foregoing, even more caespitose-depressed, greener with 

 merely a sparse hirsutulous pubescence: leaflets 5-7, plane, involute, or some- 

 what channeled, pungently long-mucronate : flowers purple, 6-8 mm. long: 

 calyx-lobes slender, as long as the campanulate tube, hirsute (a few of the 

 hairs black): pod narrowly ovate, acuminate, scarcely exceeding the calyx- 

 lobes. [A. Wolfii Rydb. Bull. Torr. Bot. Club 31: 562. 1904.] Mostly alpine 

 and subalpine; Colorado to Montana and Idaho. 



60. Astragalus caespitosus (Nutt.) Gray, 1. c. 230. Silvery-canescent and 

 densely depressed-caespitose, forming broad mats: leaves crowded on the 

 crowns, simple, or more rarely 3-5-foliolate, linear-lanceolate to linear-spatu- 

 late, tapering to a slender petiole-like base: peduncles slender, 3-8 cm. long, 

 much surpassing the leaves; the raceme several-flowered; flowers small, pur- 

 ple: pod oblong-lanceolate, acuminate, compressed and thin-edged above, pu- 

 bescent when young. A. spatulatus Sheld. 1. c. 22. Colorado to Montana. 



61. Astragalus simplicifdlius (Nutt.) Gray, Proc. Am. Acad. 6: 231. 1866. 

 Appressed silky-pubescent, growing in broad cushioned mats: leaves simple, 

 6-12 mm. long, spatulate-lanceolate, acute, frequently involute, crowding 

 the extremities of the short branches: scapes 2-3-flowered, scarcely if at all 

 exceeding the leaves; flowers purple: calyx-teeth nearly as long as the tube: 

 pod coriaceous, the ventral suture straight and acute, the dorsal gibbous. 

 (A. lingulatus Sheld. 1. c.; A. exilifolius A. Nels. Bull. Torr. Bot. Club 26: 10. 

 1899.) Dry 'sterile slopes and plains; Colorado and Wyoming. 



62. Astragalus tenellus Pursh, Fl. Am. Sept. 2: 473. 1814. Perennial, 

 somewhat glabrous: stems several, branched, 2-4 dm. high: stipules dark, at 

 least the lower sheathing; leaflets 11-21, linear or narrowly cbiong, acute or 

 obtuse, 7-12 mm. long: peduncles not exceeding the leaves, few-flowered; 



