70 LEGUMINOS^E. (PULSE FAMILY.) 



long: peduncles much surpassing the leaves : flowers rather small (about 

 inch long), iii a short and close or in fruit lengthened and open spike : pod 

 oblong-lanceolate, not stipitate, 1-celled, much surpassing the calyx. In the 

 mountains from British America to S. Colorado and westward to Utah. Sub- 

 alpine forms are often depauperate and almost stemless. 

 2. Stipules adnate to the petiole, imbricated on the short branches of the caudex 



which bears the scapes and leaves : no other ascending stems. 

 # Most of the numerous leaflets as if verticillate or fascicled in threes or fours or 



more along the rachis: scape spicately several to many-flowered: pod ovate, 



2-celled, hardly surpassing the very villoas caljjx. 



2. O. SplendenS, Dougl. Silvery silky-villous, 6 to 12 inches high: 

 flowers erect-spreading : pod erect. Whole length of the Rocky Mountains, 

 and plains along their eastern base, to the Saskatchewan. 



* * Leaflets simply pinnate. 



*- Pod wholly enclosed in the bladdery ovate-globose calyx, turgid-ovate, one-celled : 

 peduncles weak, 1 to ^-flowered. 



3. O. multieeps, Nutt. Matted cespitose, subcaulescent, 1 to 3 inches 

 high, canescently silky : leaflets 3 to 4 pairs : flowers purple : pod short-stipi- 

 tate. Alpine region of the Rocky Mountains, S. Wyoming and Colorado. 

 Nuttall's specimens are larger-leaved and less cespitose than those of subse- 

 quent collectors distributed as var. minor, Gray. 



-i - Pod nearly or quite enclosed in and completel // filling the distended and often 

 split fructiferous cali/x, turgid, pubescent, half two-celled : scapes capitately few 

 to several-flowered, surpassing the leaves, a span high : flowers over ^ inch long. 



4. O. liana, Nutt. Silvery with oppressed silky pubescence: leaflets 3 or 4 

 or rarely 6 pairs, narrowly lanceolate : flowers purple or whitish : pod turgid- 

 oblong, somewhat coriaceous, the acuminate tip barely projecting out of the 

 undivided lightly villous calyx. Torr. & Gray, Fl. May be 0. argentea, Pursh, 

 Fl. ii. 473. Mountains of Wyoming and Montana. 



5. O. lagopus, Nutt. White silky with looser and more villous hairs: leaf- 

 lets 4 or 5 pairs, lanceolate or obJong: flowers bright violet: pod ovate, thin-mem- 

 branaceous and almost bladdery, obtuse, abruptly tipped with the persistent 

 style, slightly surpassing the calyx which soon splits down one side. Jour. 

 Acad. Philad. vii. 17. Mountains of Wyoming and Montana. 



H- -)- -- Poo? well surpassing the calyx ; this at length split down one side or re- 

 maining unchanged. 



w- Bladdery-inflated and membranaceous, ovate, one-celled: scapes or peduncles 

 few-flowered, in fruit usually decumbent: very low and depressed-tufted plants. 



6. O. podocarpa, Gray. Villous, or in age glabrate: leaflets 5 to 11 

 pairs, linear-lanceolate (3 or 4 lines long) : peduncles 2-flowered, not surpassing 

 the leaves: flowers comparatively large (7 or 8 lines long), violet : pod large 

 (often an inch long), broadly ovate, puberulent, short-stipitate, neither suture at 

 all introflexed. Proc. Am. Acad. vi. 234. 0. Hallii, Bunge. Alpine and 

 subalpine, from S. Colorado to British America and perhaps to the Arctic 

 regions. 



7. O. oreophila, Gray. Silky-canescent: leaflets 3 to 5 pairs, lanceolate to 

 oblong (2 to 4 lines long) : scapes commonly surpassing the leaves, capitately 4 to 



