480 FABACEAE 



2. A. nana Nutt. Undershrub, 1-4 dm. high, glabrate or minutely strigose; 

 leaflets 15-31, elliptic or oval, rounded at both ends, mucronate, 5-10 mm. long; 

 racemes solitary, 3-6 cm. long; calyx about 3 mm. long, glabrous; lobes lance- 

 olate, acuminate, subequal; banner broadly oboyate, purple; pod about 5 mm. 

 long. A. microphylla Pursh. Hills and prairies: Man. Ida. Colo. Wyo. 

 Plain Submont. My-Je. 



3. A. canescens Pursh. Undershrub, 3-10 dm. high, white-canescent; 

 leaflets 15-47, crowded, oval or ovate-lanceolate, 9-18 mm. long, rounded at 

 the base, acute or obtuse at the apex; racemes clustered, dense, 5-18 cm. long; 

 calyx about 5 mm. long; lobes lance-subulate; banner obovate, 5 mm. long, blue; 

 pod about 4 mm. long. Dry prairies and plains: Man. Mich. La. N.M. 

 Mont. Plain. Je-Au. 



13. PS OR ALE A L. POMME DE PRAIRIE, POMME BLANCHE, 

 BREAD-ROOT, INDIAN TURNIP. 



Perennial herbs (all ours) or shrubs, with glandular-punctate foliage. Leaves 

 alternate, 3-5-foliolate, with entire or toothed leaflets. Flowers perfect, in 

 peduncled spikes or racemes. Calyx campanulate, lobes equal, or the lower 

 longer. Corolla in ours white or purplish; banner usually broad and auricled 

 at the base; wings clawed, scythe-shaped; keel shorter than the other petals, 

 incurved. Stamens diadelphous or monadelphous; anther alike. Pods broad, 

 indehiscent, or circumscissile or bursting irregularly, mostly 1 -seeded; ovules 1 or 2. 



Flowers small, less than 8 mm. long, In racemes or interrupted spikes; root not tuberous; 



pod indehiscent. (PSORALIDIUM.) 



Stem-leaves reduced to scales. 1. P. juncea. 



Stem leaves all 3-5-foliolate. 



Flowers in racemes, i. e., distinctly pedicelled. 



Pods globose; corolla white, only the keel tipped with purple. 



Racemes short and dense, elliptic 01 oblong; calyx-lobes obtuse. 



Leaflets linear to lance-oblong; fruit glabrous or sparingly strigose. 

 Leaflets lance-oblong to linear. 2. P. lanceolata. 



Leaflets narrowly linear. 3. P. micrantha. 



Leaflets spatulate or obovate; fruit long-villous. 4. P. Purshii. 

 Racemes lax, elongate, calyx-lobes acute. 



Leaves oblanceolate; pod densely villous. 5. P. stenostachys. 



Leaves narrowly linear; pod strigose. 6. P. stenophylla. 



Pods ovoid; coroJla blue or purplish; raceme elongate, lax. 



Leaflets from linear-oblanceolate to obovate; pods with short beaks. 



7. P. tenuiflora. 



Leaflets narrowly linear; pods with longer beaks. 8. P. linearifolia. 



Flowers in interrupted spikes. 



Leaves not silvery below; flowers about 6 mm. long; bracts minute. 



9. P. coJlina. 

 Leaves silvery- white at least below; flowers 7-8 mm. long; bracts at least half 



as long as the calyx. 

 ' Leaflets oval; bracts lanceolate, acuminate; calyx not inflated in fruit. 



10. P. argophylla. 



Leaflets linear ; bracts obovate ; calyx inflated in fruit. 1 1 . P. digitata. 

 Flowers large, over 1 cm. long, in dense, head-like spikes; plant with a deep-seated, 

 tuberous, farinaceous root; pod long-beaked, circumscissile or bursting irregularly. 



(PEDIOMELUM.) 



Tall, leafy and branched, usually over 4 dm. high; strigose throughout; lower calyx- 

 teeth cuspidate-acuminate. 12. P. cuspidata. 

 Low and more simple, 1-3 dm. high ; lower calyx-teeth not cuspidate-acuminate. 

 PJants with long scattered hairs, not cinereous ; leaflets linear to obovate. 



Stem and peduncles hirsute, with spreading pubescence; lower calyx-lobe not 



much larger than the rest. 13. P. esculenta. 



Stem, short peduncles and pedicels, with appressed pubescence; lower calyx- 

 lobe much broader than the rest. 14. P. hypogaea. 

 Plant cinereous, with short appressed pubescence; leaflets broadly obovate or 



rounded-spatulate. 

 Lowest calyx-lobe not much longer than the rest. 



Petioles with appressed pubescence; corolla nearly 2 cm. long. 



15. P. megalantha. 

 Petioles with spreading or reflexed hairs; corolla about 12 mm. long. 



16. P. mephitica. 

 Lowest calyx-lobe obovate or spatulate, obtuse, much larger than the rest. 



17. P. castorea. 



or 



1. P. juncea Eastw. Stem 6-10 dm. high, with virgate branches, glabrous 

 sparingly strigose; basal leaves, if present, digitately 3-5-foliolate; leaflets 



