Abarema langsdorfii

Rupert C. Barneby

31. Abarema langsdorfii (Bentham) Barneby & Grimes, comb. nov. Pithecolobium langsdorfii Bentham, London J. Bot. 3: 205. 1844. — "High mountains in Minas Geraes, Langsdorff; Brazil, Sello." — Lectotypus, Riedel s.n., comm. Langsdorff, K(herb. hooker.)! = NY Neg. 2011; isotypi, F (fragm. e P)!, K(herb. bentham.)!, LE!. — Syntypi, Sello s.n., K!; in herb. gaudichaud. 208 e Sta Catarina, G! = F Neg 28266. — Burkart, 1979, inappropriately cited Sello’s collection as the type, though did not expressly typify the name thereby. We have preferred the original spelling of the epithet to that adopted in Flora Brasiliensis and subsequently. — Feuilleea langsdorfii (Bentham) O. Kuntze, Revis. Gen. Pl. 1: 188. 1891.

Pithecolobium langsdorfii sensu Bentham, 1875: 584; 1876: 438 ("langsdorffii"). Pithecellobium langsdorjfii sensu Burkart, 1979: 116, est. 16 + map (Sta Catarina only); Lewis, Leg. Bahia 179. 1987.

Amply microphyllidious trees 3—15(—17) m with trunk attaining 2-3.5 dm dbh, the young stems and all lf- and inflorescence-axes densely pilosulous or tomentellous with either straight ascending or forwardly incurved, brown, golden-brown, or sordid hairs to 0.15-0.35 mm, the lvs strongly bicolored, the firm lfts ventrally lustrous and deeply brown-tinged either overall, or toward middle only, or discontinuously brown-spotted, dorsally dull pale olivaceous, commonly glabrous but sometimes remotely minutely ciliolate and less often thinly strigulose, the short racemes of greenish, white-stamened fls solitary or geminate in the axil of coeval lvs, immersed or nearly so in foliage. Stipules linear or linear-lanceolate 0.6-3 mm, caducous from early expanding lvs, absent from fruiting spms. Lf-formula iii-viii(-xi, in Bahia -xiv)/( 14—) 16-28(-30); lf-stks (3-)4-14(-17) cm, the petiole including discolored pulvinus 11-32 mm, at middle 0.7-1.8 mm diam, the longer interpinnal segments 8—18(—23) mm; first petiolar nectary at or close -below first pinna-pair, either cupular sessile or turbinate and incipiently stout-stipitate, round or elliptic 1-2 mm diam, always thick-rimmed and often corrugate, similar ones at all succeeding pairs or only at tip of lf-stk, or scattered, a much smaller but otherwise similar nectary randomly at tip of pinna-rachises; pinnae a little decrescent distally, the rachis of the penultimate pair (3.5—)4.5—8.5(—11) cm, the longer interfoliolar segments 1.7-3.6(-4.5) mm; pulvinules 0.3-0.6 mm, nearly as wide; lfts subequilong except at very ends of pinnae, narrowly oblong, narrowly lance- or elliptic-oblong from inequilateral, antically obtusangulate, postically cuneate base, at apex either obtuse, or obtuse apiculate, or triangular-acute, those at midrachis 7—12(—14.5) x 2-4 mm, (2.6-)2.9-4 times as long as wide; venation of 1—2(—3) nerves from pulvinule, the nearly centric but proximally incurved, thence straight midrib giving rise on the anterior side or on both to 5-8 weak ascending, mostly simple secondary nerves either weakly brochidodrome or expiring close within the scarcely revolute margin, the posterior primary nerve(s) seldom readily apparent, always very short and weak. Peduncles (3-)4—ll cm; racemes (rarely condensed capituliform) 12—27(—30)-fld, the narrowly clavate or linear receptacle (4-)6-20 mm, the fls not or little dimorphic except for pedicels progressively shorter or obsolescent distally, the 1-2 furthest fls sessile but hardly larger than the rest, their stamen-tube sometimes but not invariably a little longer; bracts obsolete; pedicels of lower fls 0.4-2(-2.5) mm; perianth 5-merous (random exceptions), sericeous-strigulose externally, the corolla sometimes more densely so than the calyx; PERIPHERAL FLS: calyx either campanulate or deeply campanulate, even subcylindric, (2.7-)3-5 (-5.6) x 1.7-2.2 mm, the unequal, obtuse teeth 0.5-1.6 mm; corolla (5.7-)6-8.5(-9.5) mm, the often very unequal lobes (1—) 1.7—2.8 x 1.1-1.3 mm; androecium (20-)24-38(40)-merous, to 23-44 mm, the stemonozone 0.7-1.6 mm, the tube 2-5(-6) mm; ovary sessile or obscurely stipitate, truncate at apex, puberulent above middle or only around the top; stigma poriform or scarcely dilated; TERMINAL FL(S): like the peripheral, but the androecial tube a trifle longer, sometimes to 2.5 mm longer than corolla. Pods usually 1 per capitulum, in profile undulately linear and evenly recurved through ±1-2 circles into a ring, the body 5.5—12 x 0.7—1 cm, 6-9(— 10)-seeded, each segment ±8-15 mm long, the stiffly papery glabrous, when ripe fuscous and coarsely reticulate valves framed by sutures ±1.2 mm wide, low-convex over each seed, not over 0.2 mm thick in section, internally orange- brown at the seed-cavities, tan between them; dehiscence downward through both sutures, the valves elastically recurved and coiling; seeds (few seen) plumply lentiform ±5-5.5 x 4.5 mm, the translucent testa loosely investing the brown embryo, charged on each face with a delicately incised, complete or almost complete pleurogram 2-2.6 x 1.6 mm, this displaced from center of seed-face toward its base.

On rocky summits, open hillsides, and in disturbed valleys of the coast ranges of SE Brazil, descending from 1050 m into restinga forest near sea level, scattered and locally plentiful from the morros of Guanabara SW into E Sta Catarina, and northward, always at submontane elevations, becoming rarer, in seasonally dry woodland habitats, through Sa. da Mantiqueira and E Minas Gerais to the sources of Río Catolé near 14°50'S in SE Bahia. — Map 27. — Fl. nearly throughout the year, most prolifically IX—II. — Pau gamba; raposeira.

The combination of many narrow, emphatically bicolored leaflets, brownish above and bright green beneath, and short dense racemes of nearly or quite homomorphic flowers distinguishes A. langsdorfii from all other abaremas native in Atlantic southern Brazil, and the species is consequently seldom mis- identified. The displacement of the pleurogram toward base of the seed is a feature unique within Abarema, though encountered rarely elsewhere in Ingeae. The cladogram (Fig. 4) suggests that on the basis of the homomorphic stamens and pubescent ovary, both homoplasious character states, A. langsdorfii is more closely related to the West Indian members of the genus than to other Brazilian ones.

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.