358 CONTRIBUTIONS FEOM THE NATIONAL HEEBARIUM. 



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. matthewsii. 

 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. bigelovii. 

 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 less 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. (Tium.) 

 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 refuse 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. drummondii. 



Plants appressed-pubescent. 



Racemes elongated, lax 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. brandegei. 



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. pattersonii. 



