LEGUMINOS^ 535 



1. ZYGIA, P. Br. 



Trees or shrubs, with slender branches armed with the persistent spinescent stip- 

 ules. Leaves petiolate, bipinnate, the pinnse few-foliolate, their rachises generally 

 marked by numerous glands between the pinnse and between the leaflets. Flowers 

 perfect or polygamous, from the axils of minute bracts, in pedunculate globose heads 

 or oblong cylindrical spikes, their peduncles in terminal panicles or axillary fascicles; 

 calyx campanulate, short-toothed; corolla funnel-shaped, the petals as many as the 

 teeth of the calyx, joined for more than half their length; stamens numerous, united 

 at the base into a tube free from the corolla; anthers minute, versatile; ovary stipi- 

 tate, contracted into a slender filiform style, with a minute terminal stigma. Legume 

 compressed, 2-valved, dehiscent, the valves continuous or interrupted within. Seeds 

 compressed, suspended transversely; funicle filiform or expanded into a fleshy aril; 

 hilum near the base of the seed; seed-coat thin or thick, marked on each of the 2 

 surfaces of the seed by a faint oval ring or oblong depression ; embryo filling the 

 cavity of the seed; the radicle included or slightly exserted. 



Zygia with more than a hundred species is widely distributed through the tropical 

 and subtropical regions of the two worlds, and is most abundant in tropical America. 

 Of the four species found within the territory of the United States three are arbo- 

 rescent. 



The generic name, from C^y6s, is the classical name of some other tree. 



CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES. 



Pinnas with 1 pair of leaflets ; valves of the leg-urae much contorted after opening ; seeds 

 surrounded by the enlarged ariloid f unicles. 1. Z*. Unguis-cati (D). 



Pinnaa with more than 1 pair of leaflets ; valves of the legume not contorted after opening ; 

 funicle of the seed not enlarged and ariloid. 



Pinnae with 3-5 pairs of leaflets ; leg'ume short-stalked, the valves submembranaceous ; 



seeds not in separate compartments. 2. Z. brevif olia (E). 



Pinnae with 2-3 pairs of leaflets ; legume sessile, the valves thick and woody, tardily 



dehiscent ; seeds in separate compartments. 3. Z. flexicaulis (E). 



1, Zygia Unguis-cati, Sudw. Cat's Claw. 



Leaves persistent, long-petiolate, with a single pair of bifoliolate pinnae, and slen- 

 der petioles faintly grooved on the upper side, ^'-1' long, and slightly and abruptly 

 enlarged at the base; rachis glandular between the short stout petiolules and between 

 leaflets; leaflets obtuse, orbicular or broadly oblong, very oblique and obtuse or rarely 

 emarginate at the apex, entire, membranaceous or somewhat coriaceous, reticulate- 

 veined, bright green and lustrous on the npper and paler on the lower surface, |'-2' 

 long and ^'-1^' wide. Flowers polygamous, pale yellow, glabrous or slightly puber- 

 ulous, opening in Florida in March and continuing to appear until midsummer, in 

 globular heads, on slender peduncles I'-l^' long fascicled in the axils of upper leaves 

 or collected in ample terminal panicles, their bracts lanceolate, acuminate, chartaceous, 

 Y long, caducous ; calyx rather less than ^^' long, broadly toothed, one quarter as long 

 as the acuminate petals barely exceeding the tube formed by the union of the fila- 

 ments; stamens purple, ^' long; ovary glabrous, long-stalked, minute or rudimentary 

 in the sterile flower. Fruit compressed, slightly torulose, stipitate, rounded or acute 

 at the apex, 2'^' long* V~i' wide, the valves reticulate-veined, thickened on the mar- 

 gins, bright reddish brown and after opening greatly and variously contorted ; seeds 



