586 TREES OF NORTH AMERICA 



Stamens distinct. 



Flowers in racemes; legume terete, contracted between the seeds. 11. Sophora. 



Flowers in panicles; legume compressed. 12. Cladrastis. 



Stamens diadelphous (9 and 1). 

 Flowers in racemes. 

 Leaves glandular-dotted. 



Leaves many-foliolate; petals free and distinct. 13. Eysenhardtia. 



Leaves simple; wings and keel-petals adnate to the tube of the stamens. 14. Dalea. 

 Leaves without glandular dots. 



Legume compressed; stipules becoming spinescent, persistent. 15. Robinia. 

 Legume turgid, -the valves unequally convex by the growth of the seeds. 

 Leaves 10-15-foliolate, without stipules or stipels; petals purple or violet. 



16. Olneya. 



Leaves 3-foliolate, with minute stipules and gland-like stipels; petals usually 



scarlet. 17. Erythrina. 



Flowers in axillary panicles; pod linear, longitudinally 4-winged. 18. Ichthyomethia. 



1. PITHECOLOBIUM Mart. 



Trees or shrubs, with slender branches armed with the persistent spinescent stipules. 

 Leaves petiolate, bipinnate, the pinnae few-foliolate, their rachis generally marked by 

 numerous glands between the pinnae and between the leaflets. Flowers perfect or polyg- 

 amous, from the axils of minute bracts, in pedunculate globose heads or oblong cylindric 

 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 base into a tube free from the corolla; 

 anthers minute, versatile; ovary stipitate, 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 ex- 

 panded into a fleshy aril; hilum near the base of the seed; seed-coat thin cr 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. 



Pithecolobium 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 arborescent. 



The generic name, from TriO^ and t\\6fiiov, relates to the contorted fruit of some of the 

 species. 



CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES. 



Pinnae with 1 pair of leaflets; valves of the legume much contorted after opening; seed 

 surrounded by the enlarged ariloid funicle. 1 . P. unguis-cati (D) . 



Pinnae 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; legume short-stalked, the valves submembranaceous; 



seeds not in separate compartments. 2. P. brevifolium (E). 



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



dehiscent; seeds in separate compartments. 3. P. flexicaule (E). 



1 . Pithecolobium unguis-cati Mart. Cat's Claw. 

 Zygia Unguis-Cati Sudw. 



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

 petiole A'-l' long and slightly and abruptly enlarged at base: rachis glandular between 



