The generic name, from πίθηξ and ἐλλὸβίον, relates to the contorted fruit of some of the species.

CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT SPECIES.

Pinnæ 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). Pinnæ with more than 1 pair of leaflets; valves of the legume not contorted after opening; funicle of the seed not enlarged and ariloid. Pinnæ with 3—5 pairs of leaflets; legume short-stalked, the valves submembranaceous; seeds not in separate compartments.2. [P. brevifolium] (E). Pinnæ 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 pinnæ and a slender petiole ½′—1′ long and slightly and abruptly enlarged at base; rachis glandular between the short stout petiolules and between the orbicular or broad-oblong leaflets, rounded and rarely emarginate at apex, rounded on one side and cuneate on the other of the oblique base, entire, thin or somewhat coriaceous, reticulate-veined, bright green and lustrous on the upper surface and paler on the lower surface, ½′—2′ long, and ½′—1½′ wide. Flowers polygamous, pale yellow, glabrous or slightly puberulous, opening in Florida in March and continuing to appear until midsummer, in globular heads on slender peduncles 1′—1½′ long fascicled in the axils of upper leaves or collected in ample terminal panicles, their bracts lanceolate, acuminate, chartaceous, ¼′ long, caducous; calyx rather less than 1/12′ long, broadly toothed, one quarter as long as the acuminate petals barely exceeding the tube formed by the union of the filaments; stamens purple, ½′ long; ovary glabrous, long-stalked, minute or rudimentary in the sterile flower. Fruit slightly torulose, stipitate, rounded or acute at apex, 2′—4′ long, ¼′—½′ wide, the valves reticulate-veined, thickened on the margins, bright reddish brown and after opening greatly and variously contorted; seeds irregularly obovoid or sometimes nearly triangular, compressed or thickened, dark chestnut-brown, lustrous, marked by faint oval rings, ⅓′ long, surrounded at base by the enlarged bright red ariloid funicle; seed-coat thin, cartilaginous.

A tree, sometimes 20°—25° high, with a slender trunk 7′—8′ in diameter, ascending and spreading branches forming a low flat irregular head, and slender somewhat zigzag branchlets slightly striately angled when they first appear, becoming terete, light gray-brown or dark reddish brown, covered with minute pale lenticels, and armed with the straight persistent rigid stipular spines broad at base and ¼′ long, or rarely minute; more often a shrub, with many vine-like almost prostrate stems. Bark of the trunk ¼′ thick, reddish brown and divided by shallow fissures into small square plates. Wood very heavy, hard, close-grained, rich red varying to purple, with thin clear yellow sapwood. The bark is astringent and diuretic, and was once used in Jamaica as a cure for many diseases.

Distribution. Florida, Captive and Sanibel Islands and Caloosa, Lee County to the southern keys; most abundant in its arborescent form on the larger of the eastern keys, and probably of its largest size in Florida on Elliott’s Key; often forming shrubby thickets; on the Bahamas, and common and widely distributed through the Antilles to Venezuela and New Granada.

2. [Pithecolobium brevifolium] Benth. Huajillo.