136 KEY AND FLORA 



palmately compound, with 3-5 linear to obovate-oblong leaflets, cov- 

 ered with glandular dots. Flowers |- in. long, loosely racemed. 

 Pod rough with glands. Prairies W. 



3. P. argophylla Pursh. SILVER-LEAVED PSORALEA. Densely 

 silvery downy, with white, close-lying hairs. Stem often zigzag, 1-3 

 ft. high. Leaves palmate ; leaflets 3-5, elliptical-lanceolate, oval or 

 obovate. Spikes interrupted, the peduncles longer than the leaves. 

 Flowers blue or purplish, j in. or more long. Pod ovate, beak straight. 

 Prairies, especially N.W. 



4. P. esculenta Pursh. POMME BLANCHE, TIPSIN, DAKOTA TURNIP. 

 Clothed with roughish hairs. Stem 5-15 in. high, erect and stout. 

 Root turnip-shaped, starchy, eatable. Leaves palmately compound, 

 with 5 lance-oblong leaflets. Flowers \ in. long, in a dense ellipsoidal 

 spike. Pod hairy, with a pointed tip. High prairies or plains, 

 especially N.W. 



XVI. AMORPHA L. 



Small shrubs, glandular-dotted. Leaves odd-pinnate. Flowers 

 purple, blue, or white, in slender spikes or racemes. Calyx 

 5-toothed, persistent. Standard obovate, concave; wings and 

 keel none. Stamens monadelphous, projecting much. Ovary 

 sessile. Pod curved, glandular-roughened, 1-2-seeded, never 

 opening.* 



1. A. canescens Pursh. LEAD PLANT, SHOE STRINGS. A bushy, 

 white, silky-downy shrub, 1-3 ft. high. Leaflets small and crowded, 

 21-49, oval or oblong-elliptical. Spikes mostly clustered at the sum- 

 mit, rather showy. Standard bright blue, roundish. Pod 1-seeded, 

 slightly longer than the calyx. Prairies. Roots very long and tough, 

 hence one common name. 



2. A. microphylla Pursh. A bushy shrub about 1 ft. high. Leaves 

 many, short-petioled ; leaflets 13-19, rigid, oval or oblong. Racemes 

 mostly solitary. Flowers fragrant; standard purplish. Prairies, 

 especially N.W. 



3. A. fruticosa L. FALSE INDIGO. A shrub, 6-15 ft. high, with 

 smooth, dark -brown bark. Leaves petioled; leaflets 15-21, short- 

 stalked, oblong, obtuse or notched, sparingly punctate with clear dots. 

 Slender flowering spikes, panicled or solitary, 4-6 in. long. Flowers 

 blue or purple. Calyx teeth short, nearly equal, downy. Pod glandu- 

 lar. River banks.* 



XVII. ROBINIA L. 



Trees or shrubs. Leaves odd-pinnate ; stipules often spiny. 

 Flowers showy, in axillary racemes. Calyx short, 5-toothed, 



