510 FABACEAE 



Calyx-teeth about as broad as long, triangular; leaflets linear or linear-oblong, 



obtuse. 23. H. junciformis. 



Calyx white-hairy; teeth triangular; legumes linear; leaflets, if any, narrowly linear 



to filiform. 24. H. junceus. 



Coralla white, pink, purplish, or rarely ochroleucous, at least the keel tipped with dark 

 purple; terminal leaflet usually well developed; leafy plants with a cespitose cau- 

 dex. 



Legume strigose, rarely becoming glabrate in age. 

 Legume arcuate. 



Leaflets 5 ; plant pulvinate-cespitose. 7. H. detritalis. 



Leaflets 7-11; plant cespitose, decumbent, but not pulvinate. 



25. H. decumbens. 



Legume straight, or the end slightly curved upwards in H. oblongifolius. 

 Leaflets strigose on both sides, usually densely canescent. 

 Leaflets narrowly linear or narrowly lance-linear. 



Calyx-teeth almost as long as the tube; corolla purplish; plant 2-4 dm. 



high. 26. H. strigosus. 



Calyx-teeth much shorter than the tube; corolla ochroleucous, only 

 the keel tipped with purple; plant less than 2 dm. high. 



27. H. tenuifolius. 

 Leaflets narrowly lanceolate or lance-oblong, 4-8 mm. long, 1-2.5 mm. 



wide; plant less than 1 dm. high. 28. H. diver gens. 



Leaflets usually glabrous above, green. 



Calyx white-hairy, its teeth one-third as long as the tube; leaflets linear 



to lance-oblong; racemes long and lax. 29. H. serotinus. 



Calyx usually black-hairy, its teeth fully half as long as the tube. 



Legumes 2-2.5 cm. long; corolla about 1 cm. long; leaflets ample; plant 



erect, 2-4 dm. high. 



Leaflets elliptic or oblong, obtuse, the terminal one short-stalked 

 and similar to the rest; lower suture of the legume decidedly 

 curved. 30. H. oblongifolius. 



Leaflets lanceolate or oblanceolate, somewhat falcate, the terminal 

 one long-stalked, longer and tapering into the rachis without a 

 distinct articulation. 31. H. decurrens. 



Legumes less than 2 cm. long; corolla 6-8 mm. long; leaflets small, less 

 than 1 cm. long; plant decumbent-cespitose, less than 2 dm. 

 high. 

 Leaflets 1-5, the terminal narrowly oblanceolate, falcate, gradually 



tapering into the rachis. 32. H. paucijugus. 



Leaflets 717, the terminal one resembling the rest, short-stalked. 

 Legumes linear with parallel sutures, 3 mm. wide. 



33. H. microcarpus. 

 Legumes obliquely oblanceolate, fully 3.5 mm. wide near the 



apex. 34. H. humilis. 



Legume glabrous from the beginning. 



Legumes about 1.5 cm. long; calyx-teeth less than half as long as the tube; leaf- 

 lets linear or narrowly lance-linear. 35. H. Palliseri. 

 Legumes 2-2.5 cm. long; calyx-teeth more than half as long as the tube; leaves 

 lanceolate to oval. 36. H. hylophilus. 



V. STENOPHYLLI. 



Calyx-teeth obtuse; leaflets many, the terminal one present. 37. H. stenophyllus. 



Calyx-teeth very acute; leaflets few, the terminal one wanting or contimious with the 

 rachis. 38. H. Episcopus. 



VI. COLLTNI. 



Pod straight. 39. H. collinus. 



Pod curved one-half to two-thirds of a circle. 40. H. curvicarpus. 



VII. FLEXUOSI. 

 Pod oblong, over 5 mm. in diameter. 



Inflorescence short; flowers about 15 mm. long; pod glabrous. 41. H. Hallii. 

 Inflorescence elongate and lax; flowers about 10 mm. long; pod pubescent. 



42. H. Fendleri. 

 Pod linear, 2-3 mm. in diameter. 



Pod abruptly contracted into a short or obsolete stipe. 



Stem decumbent ; stipe minute or obsolete. 43. H. flexuosus. 



Stem erect; stipe almost equalling the calyx. 44. H. proximus. 



Pod gradually tapering into the short stipe. 45. H. Salidae. 



VIII. MACROCARPI. 

 One species. 46. H. macrocarpus. 



1. H. lingulatus (Sheld.) Rydb. 'Leaves numerous, simple, 2-3.5 cm. long, 

 Ungulate or linear-spatulate; peduncles slender, shorter than the leaves, 1-2- 

 flowered; calyx-tube striate; teeth subulate, spreading; corolla about 1 cm. 

 long. Astragalus lingulatus Sheld. Foot-hills: Wyo. Submont. 



2. H. exilifolius (A. Nels.) Rydb. Leaves numerous, narrowly linear to 

 filiform, pungent, 2-4 cm. long, sparingly strigose; peduncles about equalling 



