130 LEGUMINOS.E. (PULSE FAMILY.) 



9. PETALOSTEMON, Michx. Prairie Cloveb. 



Calyx 5-toothed. Corolla indistinctly papilionaceous : petals all on thread- 

 shaped claws, 4 of them nearly similar and spreading, borne on the top of the 

 monadelphous and cleft sheath of filaments, alternate with the 5 anthers ; the 

 fifth (standard) inserted in the bottom of the calyx, heart-shaped or oblong. 

 Pod membranaceous, enclosed in the calyx, indehiscent, 1 -seeded. — Chiefly 

 perennial herbs, upright, glandular-dotted, with crowded odd-pinnate leaves, 

 minute stipules, and small flowers in very dense terminal and peduncled heads 

 or spikes. (Name combined of the two Greek words for petal and stamen, al- 

 luding to the peculiar union of these organs in this genus. ) 



1 . P. violaceus, Michx. Smoothish : leaflets 5, narrowly linear ; heads 

 globose-ovate, or oblong-cylindrical when old ; bracts pointed, not longer than 

 the silky-hoary calyx ; corolla rose-purple. — Dry prairies, Michigan to Minnesota 

 and southward. July. 



2. P. candidus, Michx. Smooth; leaflets 7-9, lanceolate or linear-ob- 

 long ; heads oblong, when old cylindrical ; bracts awned, longer than the nearly 

 glabrous calyx ; corolla white. — With No. 1 . July. 



3. P. villosus, Nutt. Soft-downy or silky all over; leaflets 13-17, linear 

 or oblong, small (4" - 5" long) ; spikes cylindrical ( 1' - 5' long), short-peduncled, 

 soft-villous ; corolla rose-color. — N. Wisconsin (Lake Pepin, &c. T.J. Hale) and 

 westward. 



10. AMORPHA, L. False Indigo. 



Calyx inversely conical, 5-toothed, persistent. Standard (the other petals en- 

 tirely wanting !) wrapped around the stamens and style. Stamens 10, monadel- 

 phous at the very base, otherwise distinct. Pod oblong, longer than the calyx, 

 1 - 2-seeded, roughened, tardily dehiscent. — Shrubs, with odd-pinnate leaves ; 

 the leaflets marked with minute dots, usually stipellate. Flowers violet or pur- 

 ple ; crowded in clustered terminal spikes. (Name, apop(pn, wanting form, from 

 the absence of four of the petals.) 



1. A. fruticdsa, L. (False Indigo.) Rather pubescent or smoothish; 

 leaflets 8-12 pairs, oval, scattered; pods 2-sefeded. — River-banks S. Penn. to 

 Wisconsin and southward. June. — A tall shrub : very variable. 



2. A. candscens, Nutt. (Lead-Plant.) Low (l°-3° high), whitened 

 with hoary down; leaflets 15-25 pairs, elliptical, crowded, small, smoothish above 

 with age ; pods 1 -seeded. — Prairies and crevices of rocks, Michigan to Wiscon- 

 sin and southwestward. July. — Supposed to indicate lead-ore. 



11. ROBINIA, L. Locust-tree. 



Calyx short, 5-toothed, slightly 2-lipped. Standard large and rounded, 

 turned back, scarcely longer than the wings and keel. Stamens diadelphous. 

 Pod linear, flat, several-seeded, margined on the seed-bearing edge, at length 2- 

 valved. — Trees or shrubs, often with prickly spines for stipules. Leaves odd- 

 pinnate, the ovate or oblong leaflets stipellate. Flowers showy, in hanging 

 axillary racemes. Base of the leaf-stalks covering the buds of the next year. 

 (Named in honor of John Robin, herbalist to Henry IV. of France, and his son 

 Vespasian Robin, who first cultivated the Locust-tree in Europe. ) 



