146 LEGUMINOSAE. 



lanceolate, tapering at base, 4-5 cm. long, acutish and mucronate; petioles 

 10-15 cm. long; stipules linear-lanceolate; racemes about 15 cm. long, rather 

 loose with the flowers somewhat in whorls; pedicels with appressed pubescence; 

 calyx silky; corolla blue; standard glabrous; keel bearded. Gravelly or sandy 

 soil, banks of the Clearwater River near Lewiston, Idaho. 



Lupinus sericeus Pursh. Stems stout, villous, 40-70 cm. tall; leaves 

 canescent and somewhat villous, not silvery; leaflets 6-8, oblanceolate, acute, 

 3-5 cm. long, about equalling the petioles; bracts not exceeding the buds; 

 flowers 10-12 mm. long, bluish-purple, in rather loose racemes; standard 

 pubescent. In the canyons of Snake River and its tributaries. 



Lupinus omatus Dougl. Pubescence silky or silky- villous, the whole plant 

 silvery-green, 30-40 cm. high; leaflets 6-8, oblanceolate, acute, pubescent on 

 both sides, 2—4: cm. long; petioles as long or longer; racemes rather loose, 

 short-peduncled ; flowers almost 10 mm. long, stout-pedicelled ; standard hairy. 

 Abundant on the high prairies. 



Lupinus flexuosus Agardh. (Z. omatus bracteatus Robinson; L. subulatus 

 Rydb.) Very similar to L. omatus, but usually taller, 40-70 cm. high; stems 

 usually leafless on the lower part and radical leaves few or absent; bracts 

 subulate, often recurved, conspicuously exceeding the buds, somewhat per- 

 sistent. In gravelly soil near Spokane, Piper. 



207. PSORALEA. 



Perennial herbs, usually glandular-dotted; leaves mostly 3-5- 

 foliolate, with stipules; flowers in spikes or racemes; calyx-lobes 

 5, the lower longest; corolla papilionaceous; stamens 10, dia- 

 delphous or sometimes monadelphous ; anthers of two kinds; 

 ovary sessile or short-stalked, 1-ovuled; pod seldom longer than 

 the calyx, thick, often wrinkled, indehiscent, 1-seeded. 



Leaflets broadly ovate. P. physodes. 



Leaflets lanceolate. P. lanceolata. 



Psoralea physodes Dougl. Erect or ascending, bushy, 30-50 cm. high, 

 sparsely hairy; leaflets ovate, acute, 3-4 cm. long, somewhat glandular; 

 peduncles as long as or longer than the leaves; flowers in dense short racemes; 

 bracts small; calyx black-hairy, 8-10 mm. long, in age becoming larger and 

 inflated; corolla dirty- white, the keel tipped with purple; pod membranaceous, 

 pubescent, suborbicular, enclosed in the calyx. Near Troy, Idaho, one of 

 two stations where this plant occurs east of the Cascade Mountains; west of 

 these mountains it is common. 



Psoralea lanceolata scabra (Nutt.) Piper. Erect or ascending, 30-60 cm. 

 high, sparsely puberulent, dotted throughout with coarse black glands; 

 leaflets 3, entire, narrowly or broadly oblanceolate, acute, obtuse or emarginate 

 at apex, cuspidate, 1-3 cm. long; petioles at least as long as the leaflets; pe- 

 duncles barely exceeding the leaves; racemes short, dense; flowers bluish- 

 white, 5 mm. long, short-pedicelled; calyx-teeth shorter than the tube; pod 

 subglobose, 5-6 mm. long, glandular and white-hairy. Sandy banks of Snake 

 River. 



208. TRLFOLIUM. Clover. 



Tufted or diffuse herbs; leaves mostly palmately, sometimes 

 pinnately, 3-foliolate; stipules united with the petiole; flowers in 



