Part 1, 1919] FABACEAE: PSORALEAE 17 



A perennial, with a rootstock; stem erect, 3-5 dm. high, silvery -canescent. divaricately 

 branched; leaves digitately 3-5-foliolate; stipules 5-10 mm. long, lanceolate; petioles 2-5 cm. 

 long; leaflets 1.5-4 cm. long, 5-20 mm. broad, elliptic to broadly obovate, obtuse, often mu- 

 cronate, more or less silky on both sides, usually silvery-white beneath; peduncles 3-8 

 cm. long; spikes interrupted, 2-4 cm. long; bracts ovate-lanceolate, 5-10 mm. long, long- 

 acuminate; flowers 2-4 at each node; calyx densely white-silky; tube about 2 mm. long, cam- 

 panulate; upper four lobes lanceolate, acute, about 3 mm. long, the lowest lobe lanceolate, 

 long-acuminate, 6-7 mm. or in fruit more than 1 cm. long; corolla dark-blue or purple, 8-9 

 mm. long; banner broadly obovate; pod ovoid, densely silky, 7-8 mm. long, with a flat straight 

 beak; seed brown, oval, compressed, 4 mm. long. 



Type locality: Banks of the Missouri [Dakota]. 



Distribution: Wisconsin to Saskatchewan, Wyoming, New Mexico, and Missouri. 



Illustrations: Hook. Ft. Bor. Am. pi. 52; Britt. & Brown, 111. Fl. /. 2094; ed. 2. /. 2497. 



14. Psoralidium junceum (Eastw.) Rydberg. 



Psoralea juncea Eastw. Proc. Calif. Acad. II. 6: 286. 1897. 



A perennial, with a rootstock, tufted; stem 6-10 dm. high, with numerous nearly erect vir- 

 gate branches, sparingly strigose or nearly glabrous, sparingly glandular-dotted, striate; lower 

 leaves digitately 3-5-foliolate; petioles 5-7 cm. long; leaflets oblanceolate, acute at both ends 

 or acuminate at the apex, 3-4 cm. long, those of the stem and branches reduced to small subu- 

 late scales, 3-4 mm. long, glandular-dotted and strigose; peduncles 1-1.5 dm. long; racemes 1-3 

 cm. long, few-flowered; flowers 1 or 2 at each node; bracts minute, ovate, acuminate; pedicels 

 about 1 mm. long; calyx canescent-strigose, 2 mm. long; teeth nearly equal, rounded at the 

 apex; corolla dark-blue, 5 mm. long; banner suborbicular, emarginate; pod ovoid, with a short 

 erect beak, densely silky. 



Type locality: Epsom Creek, Southeastern Utah. 

 Distribution: Southern Utah. 

 Illustration: Proc. Calif. Acad. II. 6: pi. 44. 



8. PEDIOMELUM* Rydberg, gen. nov. 



Perennials, with deep-seated round or fusiform, tuberous, farinaceous and edible roots 

 Leaves alternate, usually digitately 3-7-foliolate, but in one group with the terminal leaflet 

 borne on a prolonged rachis more or less glandular-punctate. Flowers borne in axillary pedun- 

 cled dense spikes or racemes. Calyx gibbous at the base on the upper side, 5-lobed, its tube 

 usually deeply campanulate, and the lowest lobe usually longest. Corolla blue or purple, its 

 petals not strongly veined; banner broadly oblanceolate or obovate, tapering into the claw, 

 which is broad above, attenuate towards the base, decidedly curved and boat-shaped; blades of 

 the wings obliquely usually oblong-oblanceolate, each with a distinct basal lobe and usually twice 

 as long as the claw; blades of the keel-petals similar, broader and shorter, united at the rounded 

 apex and each adnate to that of the adjacent wing at the base. Staminal tube nearly as in 

 Orbexilum but usually longer. Style abruptly bent above. Stigma capitate. Pod with an 

 oval compressed body and a long flat sword-shaped beak, as long as or longer than the body ; 

 pericarp of the body thin, free from the seed, irregularly or regularly bursting around the 

 middle, the upper part together with the beak falling off, thus setting the seed free or carrying 

 it along in falling. 



Type species, Psoralea esculenta Pursh. 



Rachis not produced beyond the lowest leaflets; leaves therefore truly digi- 

 tate; calyx and claw of the banner long. Subgenus Eupediomelum. 

 Stem usually comparatively tall, 2-10 dm. high, leafy. 



Plant with comparatively short, mostly appressed pubescence. 



Leaflets broadly obovate, distinctly petioluled, canescent beneath; 



bracts 4-6 mm. long, not exceeding the pedicels in length. 1. P. canescens. 



Leaflets narrower, sessile or nearly so, green; bracts 6-25 mm. long, 

 usually longer than the pedicels. 

 Leaflets linear; bracts shorter than the calyx. 2. P. cyphocalyx. 



* From nt&wv, plain, and ii-q\ov, apple, equivalent to the French name of the type, " Pomme de 

 Prairie." 



