TO LEGUMINOS^. (PULSE FAMILY.) 



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

 ^ inch long), in 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 villous calyx. 



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 2-foicered. 



3. O. multiceps, 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. AVyoming and Colorado. 

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

 quent collectors distributed as var. minor, Gray. 



1- -H- Pod nearly or quite enclosed in and completely filing the distended and often 

 split fructiferous calyx, turgid, pubescent, half two-celled: scapes capitately few 

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



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

 or rarely 6 pairs, narrowly lanceolate : flowers purple or Avhitish : 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. jNIountains of Wyoming and iNIontana. 



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

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

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

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

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



-♦-■*--(- Pod ivell surpassing the calyx ; this at length split down one side or re- 

 maining unchanged. 

 4H- 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 Tbng), broadly ovate, puberulent,short-stipitate, neither suture at 

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

 subalpiue, 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 



