358 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Mature pods pubescent. 
Plants sparingly appressed-pubescent with short hairs; pods 
small, not inflated, sparingly villous. ..... 8. A. goniatus. 
Plants densely pubescent; pods much larger, more or less in- 
flated, densely hairy. 
Plants small; leaves appressed silky-villous. throughout; 
pods inflated, sulcate along both sutures. 
9. A. matthewsir. 
Plants large and coarse; leaves densely tomentulose; pods 
not so much inflated, usually not sulcate. 
Leaflets large, more than 15 mm. long, oval. 
10. A. bigelovit. 
Leaflets small, mostly 10 mm. long or less, broadly 
obovate or suborbicular.......12. A. thompsonae. 
Pods not completely 2-celled. 
Dorsal suture of pod more or Jess introverted in various ways (or often not so in 
A. missouriensis). 
Lower (dorsal) suture strongly intruded, making the pod obcordate or inverted 
V-shaped in cross section; pods mostly membranous. (T1um.) 
Stipes very short (1 mm. long) or none. 
Flowers very small, barely 5 mm. long; pods sessile, only slightly 
longer than the flowers, puberulent.......... 11. A. vaccarum. 
Flowers more than 5 mm. long; pods short-stipitate and much 
larger. 
Leaflets broadly obovate, mostly retuse or obcordate; pods not 
curved, the sulcus narrow............... 13. A. cobrensis. 
Leaflets oblong-lanceolate, acute; pods strongly curved; sulcus 
broad and shallow ...........------- 14. A. humistratus. 
Stipes conspicuous, as long as the calyx or longer. 
Flowers purple, never yellow; plants slender, weak.15. A. alpinus. 
Flowers yellowish; plants erect, though sometimes slender. 
Plants loosely villous.........-...-.--------52. A. drummondit. 
Plants appressed-pubescent. 
Racemes elongated, lax.........-.--..--22+-- 16. A. rusbyi. 
Racemes short, flowers numerous and more or less crowded. 
Flowers small, hardly 10 mm. long; plants slender. 
17. A. altus. 
Flowers larger, 15 mm. long or more; plants stout. 
18. A. scopulorum. 
Lower suture not intruded as in the previous section, but intruded either as 
an interior growth forming a partial partition or as the result of dorso- 
ventral flattening; pods various. 
Lower suture slightly intruded inside the pod, forming a partial septum; 
pods not flattened exteriorly, 
Plants low, pubescent; pods rather thin (on slender peduncles, scat- 
tered) stipitate. (ATELOPHRAGMA.).......-- 19. A. brandeget. 
Plants tall, stout, almost glabrous (malodorous); pods thick and 
fleshy, becoming woody, not stipitate. (PHacopsis.) 
Plants early glabrate, only the very young parts ever pubescent. 
20. A. praelongus. 
Plants sparingly hispidulous-strigose on the stems and the lower 
surface of the leaves.............--.+-- 21. A. pattersonit. 
