KEY TO THE SPECIES 41 



5. Trifolium. Flowers in heads ; pods membranaceous. 



* * * * Leaves unequally pinnate ; stamens 5, monadelphous. 



6. Petalostenion. Flowers in dense spikes ; pods 1 or 2 seeded. 

 ***** Leaves unequally pinnate ; stamens 10, diadelphous. 



7. Glycyrrhiza. Foliage glandular-punctate ; flowers in dense spikes ; pod 

 1-celled, covered with hooked prickles. 



8. Astragalus. Foliage not punctate ; keel of corolla blunt ; pod fleshy, 

 leathery or membranous, 2-celled, only partially so, or 1-celled. 



9. Aragallus. Much like Astragalus, except that the keel of the corolla is 

 acute or tipped with a point. 



****** Leaves evenly pinnate, with tendrils ; stamens diadelphous. 



10. Vlcla. Style filiform, a tuft of hair at the summit. 



11. ]l<atliyrus. Style flattened, hairy down the inside. 



1. THERMOPSIS (Thermopsis) 



Stout perennial herbs with clustered stems from rhizomes, large free stipules 

 and entire leaflets, campanulate calyx cleft to the middle, the standard shorter 

 than the wings and the straight keel, and with narrow flattened pods. 



1. Thermopsis montana Nutt. (Mountain Thermopsis). Erect, 4-7 dm. 

 high ; leaflets oblong, silky-pubescent becoming glabrate ; the stipules exceeding 

 the petioles ; pod softly cinerous-pubescent, erect, 4-6 cm. long, about 6 mm. 

 broad, 10-12 seeded. Open woods and copses. 



2. Thermopsis dlvaricarpa Aven Nelson (River-bank Thermopsis). Leaf- 

 lets elliptic or obovate ; nearly glabrous ; the large stipules ovate, somewhat 

 Inequilateral, longer than the petiole ; pods pubescent when young, at length 

 glabrous, 8-10 cm. long, about 7 mm. broad, slightly curved and becoming widely 

 divaricate. Wet banks and bottom lands. 



3. Thermopsis arenosa Aven Nelson (Sand-dune Thermopsis). Smaller, 

 a-4 dm. high, branching ; leaflets oblanceolate to obovate ; stipules ovate to sub- 

 orbicular ; pod stipitate, divaricate from the first, sometimes drooping, slightly 

 curved, constricted between the few large seeds. Dry sandy ravines and dunes in 

 the foothills. 



3. LUPINUS (Lupine) 



Perennial herbs with palmately 5-15 foliolate leaves, showy flowers in terminal 

 racemes, a deeply 2-lipped calyx, a scythe-shaped pointed keel, and an oblong 

 flattened pod. 



1. Liupinus Plattensls Wats. (Nebraska Lupine). Simple stemmed ; 

 appressed silky-villous except on the upper face of the 7-10 spatulate leaflets ; 

 raceme terminal ; corolla blue, with a conspicuous dark spot on the standard ; 

 ovules 5-8. Sandy plains and ridges. 



2. Iiupinus hnmlcola Aven Nelson (Wyoming Lupine). Stems simple, 

 numerous, in dense tufts, with crowded, long-petioled root-leaves ; finely 

 appressed-pubescent throughout ; leaflets 7-12, oblanceolate, acute ; raceme ter- 

 minal ; flowers blue ; pods villous-pubescent, about 6-seeded. Early spring ; in 

 moist copses and wet canons. 



3. !Lupinus arg^entens Pursh. (Silvery Lupine). Bushy-branched, 3-5 dm. 

 high, appressed-silvery-pubescent, leaflets 6-8, linear-lanceolate ; racemes ter- 

 minating the branches ; flowers purple ; pods silky, 3-5 seeded. Open plains, 

 banks of ravines, etc. 



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