Pithecellobium hymenaeifolium

Pithecollobium macrosiphon Standley, Contr. U.S. Natl. Herb. 20: 191. 1919. — "Type . . . [US] 252338, collected between Tumbala [Tumbalá] and El Salto [de Agua], Chiapas, Mexico, October 29, 1985, by E. W. Nelson (no. 3398)." — Holotypus, US!; clastotypus (fragm.), NY!. — Referred by Standley & Steyermark (1946: 76) to P. lanceolatum. Pithecellobium hondurense Britton & Rose, N. Amer. Fl. 23: 18. 1928. — "Low forest, Moho River, British Honduras, March 16, 1907, M. E. Peck 721." — Holotypus, US n.v., photo, NY!.

Macrophyllidious shrubs and trees with 1-few trunks, fertile at 1.5-5.5 m, when crowded incipiently sarmentose, armed at some or all nodes with stout spinescent stipules, the annotinous branches densely lenticellate, the young branchlets, all lf-axes and inflorescence densely minutely pallid-puberulent, the olivaceous foliage subconcolorous, the stiffly papery lfts glabrous or sometimes minutely ciliolate proximally (exceptionally barbate dorsally in anterior basal angle of midrib), the dense massive spikes of greenish fls with far-exserted white androecium borne solitary or paired in distal lf-axils, the furthest sometimes forming a short pseudoraceme of spikes. Stipules at most nodes 2-12 mm, tapering from broad, either terete or laterally compressed base, either straight and widely divergent or recurved, some upper ones sometimes reduced to a conic point 1 mm or less. Lf-formula i/1, all lvs exactly 4-foliolate, the lft-pairs sometimes not quite homomorphic (the posterior one a trifle larger); lft-stks (0.8-)l-4 (of some saplings, not further described, -6) cm, shallowly open-grooved ventrally, at middle 1.2-2.4 mm diam; nectaries at tip of lf-stk and of each pinna-rachis sessile, shallowly patelliform 1-3 mm diam, either round or often crumpled; pinna-rachises (5-) 7-22 (-26) mm, dilated upward; lft-pulvinules 2-4 x 1.2-2 mm, coarsely cross-wrinkled; lfts inequilaterally ovate- or lance-elliptic from semicordate base, sometimes shortly bluntly acuminate, at very apex obtuse or obtuse mucronulate, the larger ones 5-12 x (2-) 2.4-5.7 cm, (1.7—)2—3 times as long as wide; venation pinnate, the subcentric or moderately displaced midrib gently incurved and giving rise on each side to ±6-10 major (and random intercalary) secondary nerves, brochidodrome well within the plane or loosely revolute margin, and these to an elaborate reticulum of veinlets, the whole venation bluntly prominulous on both faces or more sharply so beneath. Peduncles stiffly ascending (1.5—)2—6 cm; spikes usually dense, the fls subcontiguous, rarely more open, the deeply sulcate rachis 2-8(-14) cm; bracts deltate acuminulate 0.3-1 mm, persistent; fls homomorphic, sessile, 5-merous, the greenish perianth minutely densely puberulent or silky-strigulose overall, the androecium far exserted; calyces (sometimes a little larger upward along the spike) campanulate (1.1-) 1.3-3 x (l.l-)l.3-2.3 mm, either weakly or sharply 5-10-nerved, often a little constricted below the teeth, these depressed-deltate or -ovate 0.2-0.5 mm, or the orifice subtruncate; corolla prior to anthesis pyriform, at anthesis trumpet-shaped (7-)7.5-l 1.5 mm, the erect ovate lobes (1.5-) 1.8-3.4 x 1.4-2.2 mm; androecium 38-64-merous, (36-) 42-62(-69) mm long, the stemonozone 0.8-1.6 mm, the tube (19-)20-38(-40) mm, internally at base either obscurely callous or with well developed 5-lobed nectarial disc 0.2-0.4 mm tall surrounding the very short stipe of the ovary, this oblong, rather abruptly contracted at each end, densely silky-strigulose overall; style filiform; ovules 8-10. Pods 1-3 per spike, sessile, in profile broad- linear evenly decurved through ½-1¼ circles, 6-9.5 x 1.1-1.8 cm, laterally compressed but plump and the broad sutures not prominent, the dorsal suture undulately constricted between seeds, the ventral not or less so, the stiffly coriaceous lignescent valves externally dark red-brown, densely subvelutinously pilosulous and irregularly tumulose-cristate overall, reddish within, the cavity continuous; dehiscence follicular, through the gaping adaxial suture, exposing the seeds invested in an elaborately frilled red aril; seeds (few seen fully ripe) plumply ellipsoid, the papery testa black, lacking pleurogram, the homy embryo biconvex, without endosperm.

In deciduous and semideciduous brush-woodland, surviving disturbance in hedges and in pasture- thickets, mostly below 200 m but perhaps (in the type locality, not confirmed subsequently) to ±700 m, discontinuously dispersed in NW South and Central America: N and NW Venezuela, from Sucre to Zulia, sparingly S to the edge of the Orinoco llanos in Barinas; far N Colombia (foothills of Sa. Sta. Marta); centr. Panama; SE Mexico (N Oaxaca, S Veracruz, N Chiapas); adj. Guatemala (Petén); Caribbean lowlands of Belize; not recorded from Honduras, Nicaragua, Costa Rica. — Map 11. — Fl. intermittently throughout the year, the fls often coeval with long-persistent, dehiscent fruits. — Maiz cocido, uña-de- loro (Venezuela).

Relatively massive flower-spikes and far-exserted androecia, followed by stiff-walled, tumulose- cristate, densely pilosulous fruits render P. hymenaeifolium unmistakable. See P. lanceolatum for further discussion.