Abarema cochleata
Rupert C. Barneby
21. Abarema cochleata (Willdenow) Barneby & Grimes, comb. nov. Inga cochleata Willdenow, Sp. Pl. 4: 1020. 1806. Typus infra sub var. cochleata indicatur.
Macrophyllidious trees attaining 20(-25) m with trunk to 5 dm diam, but often flowering as bush or treelet (2-)3 m upward, the annotinous branchlets pallid-gray, the very young stems, axillary buds, and inflorescence minutely tomentellous with rusty or pallid hairs <0.2 mm, the lvs strongly bicolored, the lfts lustrous dark green (when dry dark brown) above, pale olivaceous (when dry tan and dull) beneath, the capitula of greenish white, white-stamened fls solitary and 2-3-nate in distal lf-axils, immersed in foliage. Stipules narrowly ovate 0.5-1 mm, caducous, absent from mature spms. Lf-formula i—ii(—iii)/3—4; lf-stks 0.6-5(-8) cm, the petiole including livid wrinkled pulvinus 0.6-2.6 cm, at middle 0.8-1.5 mm diam, the one (or rarely the longer of 2) interpinnal segments 8-27(-35) mm; a shallowly cupular, often crumpled nectary 0.7-1.3 mm diam either sessile or depressed into lf-stk immediately below first pair and often below further pairs of pinnae, and similar smaller ones at most nodes of pinna-rachises; pinnae when more than 1 pair accrescent distally, the rachis of further or only pair 2—8(—11) cm, the longer interfoliolar segments 8-27(35) mm; pulvinules (1.5—)2—3.5 x(0.4-)0.5-l.l mm, wrinkled; paraphyllidia not seen; lfts distally accrescent, narrowly to broadly ovate or ovate-elliptic from either broad-cuneate, or rounded, or shallowly cordate base, shortly bluntly acuminate, the distal pair 4—8(—11.2) x (2.1-)2.3- 4.3(-5) cm, 1.7-2.3(-2.7) times as long as wide; the straight centric midrib giving rise on each side to 7-13 major (and random lesser intercalary), widely spreading-incurved secondary veins brochidodrome well within the plane or incipiently revolute margin, these giving rise to a random, open 3-4-nary reticulum, the venation all immersed on upper face, sharply prominulous beneath. Peduncles (l-)1.5-4.5(-5.5) cm; capitula (15—)20—27-fld, the receptacle 2-\ mm; bracts dimorphic, 0.6-1.2 mm, the lowest broadly ovate, persistent, the further ones spatulate, deciduous; fls dimorphic, the peripheral ones shortly pedicellate, the pedicel (0.8-) 1-2.8 mm, the terminal fl sessile or nearly so, with modified androecium; perianth of all fls 5-merous, the calyx and the corolla lobes finely puberulent, the corolla-tube commonly glabrescent; PERIPHERAL FLS: calyx turbinate- campanulate, obtusely 5-angulate 1.8-2.4(-2.8) x 1.1—1.5(—1.7) mm, the triangular or deltate obtuse, dorsally convex teeth 0.25-0.5 mm; corolla 4.5-5.4 (-6.3) mm, the ovate-lanceolate lobes (1.2-) 1.4-1.9 mm; androecium 12-22-merous, 14-23 mm, the stemonozone 0.5-0.9 mm, the tube 2-3.2 mm; TERMINAL FL: calyx 2.25-3 mm; corolla 5-7 mm; stemonozone 1.7-2 mm; staminal tube 7-12 mm, at least shortly exserted; ovary of all fls narrowly ellipsoid, symmetrically conical at apex, glabrous. Pods 1-3 per capitulum, either sessile or commonly short-stipitate, in profile undulately broad-linear, evenly incurved through 3/4-1½circles, 8.5-15 x (1.2-) 1.3-1.7 cm, 7-12(-14)-seeded, the glabrous, at first green then orange or red, when ripe fuscous, stiffly leathery or ligneous valves framed by sutures ±1.5-2 mm wide, convex or domed over each seed, internally red- orange-scurfy; dehiscence through both sutures, the valves ultimately both recurved and coiled; seeds plumply lentiform, in broad view either round or elliptic, 5.5-11 x 5.5-8 mm, the translucent testa when fresh gray or whitish in lower half, appearing blue-gray distally, becoming drab when old, loosely investing the embryo and therefore wrinkled when dry, pleurogram 0.
Abarema cochleata differs from other paucifoliolate abaremas native to middle and eastern Amazonia by leaflets symmetrically ovate and short-acuminate that assume a characteristic brown and tan coloring when dried. Within its range of dispersal A. microcalyx var. parauaquarae differs in inequilaterally obovate leaflets combined with mounded, small-pored leaf-nectaries; A. villifera in asymmetrically obovate leaflets softly pubescent beneath; whereas A. mataybifolia has leaflets nearly twice as large, borne on longer pulvinules (5-8, not 1.5-3.5 mm), peripheral flowers of the capitulum a little longer, and a broader pod. The differential characters of A. campestris are noted under that species. Abarema jupunba var. trapezifolia, sometimes similar in leaf-formula, has rhombic leaflets puberulent dorsally.
Pithecolobium moniliforme, described from a single tree and collected subsequently only once, differs from typical A. cochleata in texture of the pod’s valves, but apparently in no other feature, and we consider it here as a variety, not specifically separable. While the exocarp of the pod of A. cochleata is ordinarily <1 mm thick in cross-section, that of P. moniliforme is thickened over each seed into a woody dome nearly 5 mm thick, and the venation, ordinarily superficial and sharply defined, is differentiated neither superficially nor internally. The pods appear as though galled, but the seeds are well formed. In English commentary Ducke emphasized the peculiar fruit of P. moniliforme, but in the Latin diagnosis he stated that it differed from P. cochleatum in foliage, though he did not specify in what respect. The leaf- formula is i/3, but this occurs in some plants of the Amazon delta that have a pod typical of A. cochleata. In size, outline, texture, color, and venation of the leaflets A. cochleata and P. moniliforme are identical, as are the capitula and the individual flowers.
References: [Article] Barneby, Rupert C. & Grimes, James W. 1996. Silk tree, guanacaste, monkey's earring: a generic system for the synandrous Mimosaceae of the Americas. Part I. Abarema, Albizia, and allies. Mem. New York Bot. Gard. 74: 1-292.