LEGUMINOS^E. (PULSE FAMILY.) 63 



+- Pod long-stipitate, not sulcate, cross-section oval : flowers white or bluish, keel 



violet. 



20. A. aboriginum, Rich. Hoar //-pubescent or subvillous : stems numer- 

 ous, rigid : leaflets 3 to 6 pairs, linear or oblong-lanceolate : pod semi-elliptic. 

 Mountains of Colorado, northward throughout VV. British America. 



21. A. glabriusculus, Gray. Like the last: glabrous or with short 

 scattered hairs: leaflets thinner, green, linear-lanceolate: pod lanceolate-subfal- 

 cate, the stipe 2 to 3 times longer than the calyx. Proc. Am. Acad. vi. 204. 

 Mountains of Colorado and British America. 



H- -t- Pod short-stipitate, cross-section obovate, pubescent with more or less nigres- 

 cent hairs: flowers white. 



22. A. Robbinsii, Gray, var. OCCidentalis, Watson. Pod much com- 

 pressed, tapering at base to a very short stipe, with no indication of a dorsal 

 sulcus. Bot. King's Exp. 70. S. W. Colorado and Nevada. 



# # Pod more coriaceous, black- or rarely cinereous-pubescent, more or less triangu- 

 lar and semi 2-celled, the dorsal suture sulcate-impressed. 



t- Pod lens-shaped, the cross-section obcordate, the ventral suture a little the more 



gibbous. 



23. A. Oroboides, Hornem., var. AmericanuS, Gray. Subcinereous- 

 puberulent : steins 1 to l feet high : leaflets 5 to 7 pairs, oblong and oval or 

 often linear-oblong : flowers in a long secuud raceme, the wings exceeding the 

 keel : pod with gray pubescence ; stipe very short. Proc. Am. Acad. vi. 205. 

 In the Rocky Mountains from Colorado northward into British America, 

 thence eastward to Labrador. 



H- *- Pod triangular, more impressed, the cross-section deeply obcordate, rather 

 straight or incurved, gibbous on the back. 



24. A. alpinus, L. Hairy-pubescent or glabrous: leaflets 6 to Impairs, 

 oval or oblong : racemes short or subcapitate, many-flowered : wings little if at 

 all exceeding the rather large keel: pod straight or recurved, black-villous or 

 -pubescent ; stipe usually exceeding the calyx. Colorado, Wyoming, and north- 

 ward to Arctic America; also in Maine and Vermont. 



25. A. sparsiflorus, Gray. Slightly appressed-pilose, glabrate : leaflets 

 4 to 6 pairs, obovate or subrounded : peduncles 3 to 10-flowered: the emargi- 

 nate or bifid banner and the wings much exceeding the incurved keel: pod in- 

 curved, mottled; stipe very short. Proc. Acad. Philad. 1863, 60. Colorado. 



11. Closely resembling the last, but villous or canescent, lower, and ivith yellow- 

 ish flowers: pod semi-ovate or oblong, turgid, coriaceous, subtriangular, with 

 the back gibbous and more or less impressed, the ventral suture prominent. 



26. A. lotiflorus, Hook. Heads few-flowered : corolla little exceeding 

 the calyx : the cross-section of the pod obovate, retuse, or usually broadly ob- 

 cordate toward the base. From Colorado and Wyoming to Texas, Nebraska, 

 and Hudson's Bay. 



12. Pod sessile, mostly thick coriaceous and obcompressed, the impressed dorsal 

 suture more or less approaching the ventral, not 2-celled, pubescent. Low, 

 white-silky or hoary : flowers spicate or subcapitate, usually violet or purplish. 



