PAPILIONACEAE. 



[VOL. II 



2. Homalobus montanus (Nutt.) Britton. 

 Prickly Milk Vetch. (Fig. 2152.) 



Kentrophyta montana Nutt. ; T. & G. Fl. N. A. i: 353. 1838. 

 Kentrophyta viridis Nutt.; T. & G. Fl. N. A. i: 353. 1838. 

 Astragalus Kentrophyta A. Gray, Proc. Acad. Phil. 1863: 

 60. 1863. 



Densely tufted, intricately branched, 2 / -io / high, 

 finely canescent. Stipules linear-lanceolate, spiny- 

 tipped, 2 // -5 // long; leaflets 3-7, linear, rigid, spiny, 

 widely spreading, 3 // -6 // long, ^ /x wide; flowers 1-4 

 together in the axils, nearly sessile, yellowish-white or 

 bluish-tinged, 2 // ~3 // long; pod sessile or very short- 

 stalked, i-3-seeded, ovoid-oblong, acute, coriaceous, 

 dehiscent,' pubescent, 3 // -4 // long. 



In dry, rocky places, Nebraska to New Mexico, Nevada 

 and the Northwest Territory. June-Sept. 



3. Homalobus caespitdsus Nutt. Tufted 

 Milk Vetch. (Fig. 2153.) 



Homalobus caespitosus Nutt. ; T. & G. Fl. N. A. i: 352. 1838. 

 Astragalus caespitosus A. Gray, Proc. Am. Acad. 6: 230. 1804. 



Silvcry-canesccnt, much tufted from a deep root, $'-6' 

 high. Stipules scarious, much imbricated, lanceolate, 

 acuminate, 4"-6" long; leaves simple, spatulate-linear, 

 acute, i / -2 / long, or some of them 3-5-foliolate, with ob- 

 long-linear leaflets; peduncles scapiform, exceeding or 

 equalling the leaves; flowers purple, 4 // -5 // long, in heads 

 or short spike-like racemes; pod erect, sessile, few-seeded, 

 oblong, acute, coriaceous, slightly curved, pubescent, 4"- 

 5" long; calyx-teeth subulate. 



In dry rocky soil, Nebraska and Colorado, north to the *j 

 Northwest Territory. May-July. 



26. OROPHACA Britton. 



Perennial, silvery or villous-pubescent low tufted herbs, with branched woody caudices, 

 deep roots, membranous scarious stipules, sheathing and united below, and digitately 

 3-foliolate (rarely 5-foliolate) leaves, resembling those of Lupines. Flowers few, capitate or 

 racemose, the clusters sessile or pcdunclcd. Keel of the corolla blunt. Pod coriaceous, 

 completely i-celled, ovoid or oval, few-seeded, villous, partly or wholly enclosed by the calyx. 

 [Greek, mountain vetch.] 



Three known species, the following, and one in Colorado and Wyoming. 



Flowers yellowish, 1-3 together in the axils. 

 Flowers blue-purple, in peduncled racemes. 



1. O. caespitosa. 



2. O. sericea. 



i. Orophaca caespitdsa (Nutt.) Britton. Sessile-flowered Milk Vetch. 



(Fig. 2154.) 



Astragalus /n'/AjV/MJ Pursh, Fl. Am. Sept. 740. 1814. Not 



Pall. 1800. 



Phaca caespitosa Nutt. Gen. 2: 98. 1818. 

 Phaca argophylla Nutt.; T. & G. Fl. N. A. i: 342. 1838. 

 A. hyalinns M. E. Jones, Proc. Cal. Acad. (II. ) 648. 1895. 



Silvcry-canescent, densely tufted from a deep root, 

 2 / -4 / high. Stipules scarious, imbricated, glabrous, 

 ovate-lanceolate, 3 // -4 // long; leaves digitately 3-5- 

 foliolate, slender- petioled; leaflets oblong or oblanceo- 

 late, acute or obtusish at the apex, narrowed or cuneate 

 at the base, 6"-8" long; flowers yellowish, 6"-8" 

 long, sessile in the axils of the leaves; pod i-celled, 

 sessile, ovoid, acute or acuminate, coriaceous, dehiscent, 

 villous-pubescent, enclosed by the calyx, 2 // ~3 // long. 



Prairies, Nebraska and South Dakota to Montana and the 

 Northwest Territory. May-July. 



