LEGUMINOS.E. (PULSE FAMILY.) 141 



* * Pods straight and linear, fiat : peduncles short, 1 -few-flowered at the summit : 



flowers small : keel less incurved. 



4. P. paucifibrus, Benth. Annual ; stems diffuse, but twining, slender, 

 pubescent ; leaflets varying from oblong-lanceolate or ovate-oblong to linear. 

 (P. leiospermus, Torr. $- Gr.) River-banks, Illinois (Mead) and southwest- 

 ward. July - Sept. Flowers 3" long, purple. Pod 1' long, pubescent. 



26. CENTBOSEMA, DC. SPURRED BUTTERFLY-PEA. 



Calyx short, 5-cleft. Corolla, &c. much as in Clitoria, but the spreading 

 standard with a spur-shaped projection on the back near the base : keel broad. 

 Style bearded at the apex around the terminal stigma. Pod long and linear, 

 flat, pointed with the awl- shaped style, many-seeded, thickened at the edges, 

 the valves marked with a raised line on each side next the margin. Twining 

 perennials, with 3-folidlate stipellate leaves, and large showy flowers. Stipules, 

 bracts, and bractlets striate, the latter longer than the calyx. (Name from 

 /teVrpoi/, a spur, and o-^/xa, the standard. ) 



1. C. Virginianum, Benth. Bather rough with minute hairs; leaflets 

 varying from oblong-ovate to lanceolate and linear, very veiny, shining ; pedun- 

 cles 1 -4-flowered ; calyx-teeth linear-awl-shaped. Sandy woods, from Mary- 

 land southward. July. Corolla 1 ' long, violet. Pods straight, 4 y - 5' long. 



27. CLITOBIA, L. BUTTERFLY-PEA. 



Cajyx tubular, 5-toothed. Standard much larger than the rest of the flower, 

 erect, rounded, notched at the top, not spurred on the back : keel small, shorter 

 than the wings, incurved, acute. Stamens monadelphous below. Style bearded 

 down the inner face. Pod linear-oblong, flattish, knotty, several-seeded, pointed 

 with the base of the style. Erect or twining perennials, with mostly pinnately 

 3-foliolate stipellate leaves, and very large flowers. Peduncles 1 - 3-flowered : 

 bractlets opposite, striate. (Derivation recondite.) 



1. C. Mariana, L. Smooth; leaflets oblong-ovate or ovate-lanceolate; 

 stipules and bracts awl-shaped ; peduncles short, 1 - 3-flowered. Dry banks, 

 E. New York to Virginia and southward. July. Low, ascending or twining ; 

 the showy pale-blue flowers 2' long. 



28. AMPHICABPJ3A, Ell. HOG PEA-NUT. 



Flowers of 2 kinds ; those of the racemes from the upper branches perfect, but 

 seldom ripening fruit ; those near the base and on creeping branches with the 

 corolla none or rudimentary, and few free stamens, but fruitful. Calyx about 

 equally 4- (rarely 5-) toothed : bractlets none or minute. Keel and wing-petals 

 similar, almost straight ; the standard partly folded round them. Stamens dia- 

 delphous. Style beardless. Pods of the upper flowers, when formed, somewhat 

 scymetar-^haped, 3 - 4-seeded ; of the lower ones commonly subterranean, obo- 

 vate or pear-shaped, fleshy, ripening usually but one large seed. Low and 

 slender perennials; the twining stems clothed with brownish hairs. Leaves 

 pinnately 3-foliolate : leaflets rhombic-ovate, stipellate. Flowers small, in clus- 



