LEGUMINOSJE. (PULSE FAMILY.) 63 



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



violet. 



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

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

 Mountains of Colorado, northward throughout W. 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. 



■i- f- 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. 

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



gibbous. 



23. A. oroboides, Hornem., var. AmerieanuS, Gray. Subcinereous- 

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

 often linear-oblong : flowers in a long secund 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. 



+- +- 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 12 pairs, 

 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 

 i 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 with yellow- 

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

 the back gibbous and more or less impressed, the ventral sttture 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. — Prom Colorado and Wyoming to Texas, Nebraska, 

 and Hudson 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. 



