136 LEGUMINOS^. (pulse FAMILY.^ 



-H- -1- Pod not completely 2-ceUed. 

 -w- Pod stipitate, pendent. 



8. A= alpinus, L. Diffuse (6- 12' high), smooth or slightly hairy ; leaf- 

 lets 13 - 25 ; lowers violet-purple, or at least the keel tipped with \iolet or blue ; 

 calyx campanulate ; pod narrowly oblong, short-acuminate, black-pubescent, 

 triangular-turgid, deeply grooved on the back, straight or curved, its stipe usu- 

 ally rather exceeding the calyx. — Rocky banks, Lab. to Maine and X. Vt. 



9. A. Robbinsii, Gray. Nearly smooth and erect (1° high), slender; 

 leaflets 7-11 ; calyx more ohlong; flowers white; pod oblong (6" long), ob- 

 tuse or acutish, minutely darkish-pubescent, somewhat laterally compressed, not 

 dorsally sulcate or obsoletely so, straight or somewhat incurved, rather ab- 

 ruptly narrowed at base into the often included stipe. — Rocky ledges, Vt, 



10. A. racemosus, Pursh. Stout (1-2° high), erect or ascending, ap- 

 pressed-pubescent or glabrate ; leaflets 13-25; flowers numerous, white, pen- 

 dent ; calyx campanulate, gibbous, white-pubescent ; pod straight, narrow, 

 r long, acute at both ends, triangular-compressed, deeply grooved on the back, 

 the ventral edge acute. — Neb. to Mo., and westward. 



4H- ++ Pod sessile. 



11. A. gracilis, Xutt. Subcinereous, slender (1° high or more); leaflets 

 11-17, linear, obtuse or retuse ; racemes loose; flowers small (3" long) ; pods 

 pendent, 2 - 3" long, coriaceous, elliptic-ovate, concave on the back, the ventral 

 suture prominent, white-hairy, at length glabrous, transversel y veined. — Minn, 

 to Neb. and ]Mo., and westward. 



12. A. distortus, Torr. & Gray. Low, diffuse, many-stemmed, subglsr 

 brous ; leaflets 17-25, oblong, emarginate ; flowers in a short spike, pale-purple ; 

 pod ovate- or lance-oblong, curved, 6 - 9" long, glabrous, thick-coriaceous, some- 

 what grooved on the back, the ventral suture nearly flat. — 111. to Iowa, Mo., 

 Ark. and Tex. 



13. A. lotifl6rus, Hook. Hoary or cinereous with appressed hairs ; stems 

 very short ; leaflets 7-13, lance-oblong ; flowers yellowish, in few-flowered 

 heads, with peduncles exceeding the leaves or very short ; calyx campanulate, 

 the subulate teeth exceeding the tube ; pod oblong-ovate, 9-12" long, acuminate, 

 acute at base, canescent, the back more or less impressed, the acute ventral 

 suture nearly straight. — Sask. to Neb. and Tex., west to the mountains. 



14. A. Missouriensis, Nutt. Short-caulescent, hoary with a closely 

 appressed silky pubescence ; leaflets 5-15, oblong, elliptic or obovate ; flowers 

 few, capitate or spicate, 5 - 8" long, violet : calyx oblong, the teeth very slender ; 

 pod oblong (1' long), acute, obtuse at base, pubescent, nearly straight, obcom- 

 pressed or obcompressed-triangular, depressed on tlie back and the ventral su- 

 ture more or less prominent, transversely rugulose. — Sask. to Neb. and N. Mex. 



II. Pod l-celled, neither suture being inflexed or the ventral more intruded than 



the dorsal. — Phaca. 



15. A. Cooperi, Gray. Nearly smooth, erect (1 -2° high) ; leaflets 11-21, 

 elliptical or oblong, somewhat retuse, minutely hoary l)eneatli ; flowers white, 

 rather numerous in a short spike ; calyx dark-pubescent ; pod coriaceous, in- 

 flated, ovate-globose (Q -9" long), acute, glabrous, slightly sulcate on both sides, 

 cavitv webbv. — Out. and western N. Y. to Minn, and Iowa. 



