456 FABACEAE 



Tribe X. VICIEAE. 



Style fliiform, hairy all around and below the apex; stamen-tube usually obUque at the 

 summit. 42. Vicia. 



Style flattened towards the apex, hairy on the inner side; stamen-tube usually trimcate 

 or nearly so. 43. L.\THYRUS. 



Tribe XI. PHASEOLEAE. 



Leaves 5-7-foliolate; style glabrous. 44. Apios. 



Leaves 3-follolate; style bearded along the inner side. 45. Strophostyles. 



1. SOPHORA L. 



Trees or shrubs, or (ours) perennial herbs, with rootstocks. Leaves odd- 

 pinnate, with bristle-like stipules. Flowers perfect, in racemes. Calyx cam- 

 panulate, 5-lobed. Petals clawed, white, yellow, or violet, nearly equal in 

 length; banner suborbicular, notched at the apex; keel 2-beaked at the apex. 

 Stamens 10; filaments distinct or nearly so. Pod nearly terete, usually monili- 

 form, indehiscent or tardily dehiscent. Seeds globose. 



1. S. sericea Nutt. Perennial, with a creeping rootstock; stem 1-3 dm. 

 high, silky-canescent, leafy; leaflets 15-23, elliptic or obovate, canescent; caljoc 

 gibbous on the upper side; lobes lanceolate to triangular; corolla about 15 mm. 

 long, ochroleucous; keel with two subulate beaks; pod 3-5 cm. long, constricted 

 between the seeds. Dry prairies, plains, and hills: S.D. — Tex. — Ariz. — Wyo. 

 Plain — Submont. Ap-Je. 



2. THERMOPSIS R. Br. Yellow Pea, Golden Pea, Prairie Bean. 



Perennial herbs, with creeping rootstocks. Leaves alternate, with foUaceous 

 stipules, digitately 3-foliolate, with entire leaflets. Flowers perfect, in racemes. 

 Calyx campanulate, 5-lobed, the lobes nearly equal, or the upper two united. 

 Corolla in ours yellow; banner with a broad spreading blade and reflexed margins; 

 keel as long as the wings or longer. Stamens 10, distinct; anthers nearly alike. 

 Pod narrow, flat, 2-valved, many-seeded. 



Legume erect or ascending. 

 Fruit straight. 



Legume strictly erect and aopressed to the peduncle, densely pubescent. 



Leaves strongly ascending; leaflets lance-oblong or oblanceolate; stipules 

 lanceolate oi oblong, more than twice as long as broad; raceme dense. 



1. T. montana. 

 Leaves spreading; leaflets rhombic-elliptic to elliptic-oblong; lower stipiiles at 

 least ovate, very oblique, less than twice as long as broad. 

 Raceme lax; legume straight. 2. T. ovnta. 



Raceme dense; legume somewhat curved. 4. T. xylorrhiza. 



Legume ascending, sparingly pubescent; stipules broad; raceme few-flowered. 



3. T. pinetorum. 

 Fruit arcuate with spreading tips. 



Legume 4-6 cm. long. 4. T. xi/lorrhiza. 



Legume 8-10 cm. long. 5. T. diraricarpa. 



Legume strongly divaricate or reflexed; inflorescence short. 



Fruit mostly horizontal, merely arcuate. 6. T. arenosa. 



Fruit reflexed, curved into half a circle or more. 



Leaves glabrous above. 7. T. rhombifoUa. 



Leaves silvery on both sides. 8. T. annulocarpa. 



1. T. montana Nutt. Stem 3-6 dm. high, slightly angled, glabrous or 

 sparingly hairy; leaflets 3-6 cm. long, glabrous above, sparsely pubescent beneath; 

 inflorescence rather dense, 1-1.5 dm. long; corolla 15-20 mm. long; pod linear, 

 4—6 cm. long, 5 mm. wide. T. slricla Greene. Meadows: Mont. — Colo. — Utah 

 —Ore.— Wash. Submont.— Monl. My-Jl. 



2. T. ovata (B. L. Robins.) Rydb. Stem 3-7 dm. high, strict, branched 

 above; leaflets rhombic-elliptic or elliptic-oblong, 6-10 cm. long, glabrous; 

 racemes 1-2 dm. long; corolla 2-2.5 cm. long; pod straight, about 6 cm. long, 

 sparingly villous. T. montana ovata B. L. Robins. Valleys: Wash. — Ida. — 

 Utah. Submont. Ap-Je. 



3. T. pinetorum Greene. Stem 2-4 dm. high, striate, glabrous or si)ar- 

 ingly pubescent above; stipules ovate, 2-4 cm. long; leaflets oblong or obovate- 

 oblong, 3-5 cm. long, obtusish, glabrous above, si)aringly pubescent beneath; 

 racemes short, 3-5 cm. long; fruit linear, 5-7 cm. long, 6 mm. wide, appressed- 





