7. Abarema macradenia (Pittier) Barneby & Grimes, comb. nov. Pithecollobium macradenium Pittier, Contr. U.S. Natl. Herb. 20: 465. 1922. — " ... at Monte Lirio, Canal Zone, Panama, May 6, 1912, by E. D. Christopherson (no. 196)." — Holotypus, US 716842!, isotypi, NY! = NY Neg. 10365, US!. —Samanea macradenia (Pittier) Britton & Rose, N.Amer. Fl. 23: 35. 1928.

Pithecellobium macradenium sensu Elias, Bot. Gaz. 133: 38, figs. 1-7 (anatomy of lf-nectaries). 1972.

Amply macrophyllidious, unarmed, broad-crowned trees 9-36 m when fertile and attaining 12 dm dbh, the longitudinally sulcate young stems, all lf-axes, and inflorescence densely sordid-puberulent with incurved hairs to 0.1-0.2 mm, the lvs strongly bicolored, the thinly papery lfts on upper face olivaceous (brunnescent) and except for minutely ciliolate midrib glabrous, on lower face pale green and minutely thinly strigulose (along midrib sometimes villosulous), the capituliform racemes of pale green, white-stamened fls solitary or 2-3-nate in the axil of coevally expanding lvs or sometimes forming when young a subcorymbose panicle, the woody fruits long persistent below the new lvs. Stipules subulate to 2-5.5 mm, very early caducous from a small pallid scar. Lf-formula of lvs associated with fls or fruits (ii—)iii—vi/7—12, that of sapling lvs, described below in brackets only, vi-xii/11-20; lf-stks (7-)9-24 [25— 60] cm, the petiole 2.5-6.5 [6-18] cm, the longer interpinnal segments (2-)2.54- [3.5-7.5] cm; petiolar nectaries of lvs associated with flowers dimorphic, the first one, situated shortly below insertion of first pair of pinnae, sessile campanulate 5-15 x 4-11 mm, its walls leathery and striate lengthwise, becoming subligneous in age, the nectaries between further pairs of pinnae either sessile or stipitate, cupular ±1 mm diam, and yet smaller cupular ones between some distal lft-pairs [nectaries of ample juvenile lvs all small or the first petiolar one lacking]; pinnae accrescent distally, the rachis of furthest pair 8-15 [15-27] cm, the longer interfoliolar segments 11-19 mm; pulvinules in dorsal view 0.6-1.2 x 0.6-0.8 mm, finely wrinkled; lfts proximally decrescent, those from mid-rachis upward (except for slightly broader distal pair no further mentioned) subequiform, in outline obliquely oblong-elliptic or very obtusely rhombic around a diagonal, straight or slightly incurved midrib, inequilaterally flabellate at base, broadly rounded and muticous at apex, the larger ones (27)30-46 x 13-20 [9-14] mm, 1.8—2.7(—3) times as long as wide; the midrib giving rise on each side to 7-10 major (and random weaker intercalary) secondary nerves widely ascending to anastomosis well within the subrevolute margin, the tertiary venules weak and random, all venation subequally prominulous on each face. Peduncles 5-12 cm, in fruit lignescent 2-5 mm diam; racemes ±30-45-fld, the narrowly clavate receptacle 5-11 mm; bracts caducous, linear-spatulate ±2 mm (or the first one, lacking a subtended fl, broader); fls subhomomorphic except for distal ones slightly larger and sessile or very shortly pedicellate, their androecium hardly modified; pedicel of lower peripheral fls 0.7-3.6 x ±0.3 mm, that of distal ones progressively shorter; perianth 5-merous, finely yellowish silky-puberulent externally, the corolla-lobes ciliolate with white coralloid trichomes; calyx campanulate 2.5-4 x 1.6-2.2 mm, the ovate or depressed-deltate, sometimes very unequal teeth (0.2-) 0.4-1.2(-l.4) mm; corolla narrowly trumpet-shaped (6.5-)7-9.5 mm, the ovate acute lobes 1.4-3.2 x 1.3-1.8 mm; androecium 18-26-merous, to 18-25 mm long, the stemonozone 1.2-2 mm, the tube 3.5-7.5 mm; ovary glabrous truncate; style a little shorter or longer than longest stamens, the stigma punctiform. Pods usually 1 per capitulum, subsessile, in profile broad-linear but evenly recurved through 3/4 to 1.5 circle, 9-14 x 1.3-2.4 cm, compressed but strongly turgid over each seed and depressed between them, the prominent sutures 3-5 mm wide, the exterior (seminiferous) one shallowly undulate, the interior one evenly curved, the woody valves externally coarsely rugulose, fuscous-castaneous glabrous, nearly 3 mm thick over each seed-locule, the transverse depressions between seeds 3-8 mm deep, the crustaceous endocarp ±0.5 mm thick in section, the seed-locules castaneous or dark crimson internally; funicles ligulate, coiled distally; dehiscence of the genus, the valves rigidly recurved and coiled; seeds 10-15, horizontal, in broad view 6.5-8 x 5-7 mm, the translucent testa white in proximal ^xA-h, pale tan distally, in section at most 0.2 mm thick, loosely investing the scarcely rugulose blue embryo, pleurogram 0.

In humid primary forest, sometimes surviving disturbance as a shade tree in pasture, apparently local in SE Central America and in N Pacific South America: Nicaragua (Zelaya, at 13°3'N); in hill-country at 550 m in S Costa Rica (Puntarenas); near sea level in the Canal Zone of Panama (Isla Barro Colorado; Mte Lirio; Fort S. Lorenzo); and at 70-220 m in prov. Los Ríos, Ecuador (Palenque Biological Station; Jauneche Forest; Pichilingue). — Map 11. — Fl. in Central America I-V, in Ecuador VIII-IX, the full season probably greater than recorded. — Coralillo (Nicaragua), guavo, guavo de montana (Costa Rica); bantano (Ecuador).

This is a species ordinarily recognized by tall arboreal stature and either by the enlarged leathery bellshaped petiolar nectary on leaves associated with flowers or by the woody pod grossly enlarged over the seed-locules, or by both. It appears most closely related to the Guyanan A. curvicarpa, which has a comparable ligneous pod but patelliform leaf-nectaries, significantly different leaf-formula, and an extended raceme-axis.

There is incipient racial differentiation between the Central American and Ecuadorean populations of A. macradenia, but too little marked as yet to deserve taxonomic separation. The calyx in Ecuador is on the average smaller (2.5-3.3, not 3.3-4 mm long), and the pod rather narrower (mostly 13-17, not 19-24 mm wide), with shallower transverse depressions between seeds. A sterile specimen from Pacific Colombia (Valle: 10 km NW of Buenaventura; A. Gentry 56959, MO, NY), not certainly of this species, suggests a link between the at-present widely dissevered known localities. The enlarged petiolar nectary is sometimes eaten down to the base, perhaps by ants, and is not developed in the leaves of saplings or stump-sprouts, leaves twice or more the size of those on fertile branchlets of adult trees.