Abarema obovata

Rupert C. Barneby

26. Abarema obovata (Bentham) Barneby & Grimes, comb. nov. Calliandra (?) obovata Bentham, London J. Bot. 3: 101. 1844. — "Brazil, Lobb." — Holotypus, Lobb 83, from southern Brazil, the locality unknown, K(herb. hooker.)! = NY Neg. 2008. — Erroneously equated by Bentham, 1875: 583 with Pithecolobium lusorium.

Trees 4-15 m, closely resembling and related to A. filamentosa, but the lfts never fully glabrous, either pilosulous beneath or merely ciliolate, and sometimes with a secondary nerve from the pulvinule, in fruit resembling both A. filamentosa and A. brachystachya. Stipules 0.5-3 mm. Lf-formula (i—)ii—iii(—iv)/3—4(—5, exceptionally -7), the lfts of ampler lvs to 24-4-0(-60 mm); lf-stks (1.5—)2.5—8 cm, the petiole 1-3 cm, the longer interpinnal segments 8-35 mm; nectary between first pair of pinnae either shallowly cupulate or distinctly pored, ±0.8-1.2 mm diam; rachis of longer pinnae 4—8 cm, the interfoliolar segments 12-22 mm; lft-pulvinules 0.8-2 x 1-1.2 mm; lfts obovate or rhombic-obovate, obtuse or subemarginate, the larger ones 3-6 x 2-3.5 cm. Inflorescences and fruit essentially as in A. brachystachya, the calyx of peripheral fls ±3 mm and corolla ±5.5-6.5 mm.

On wooded hillsides, sometimes in mata do cipó, 400-1030 m, known with certainty from E- and N- centr Minas Gerais, on both slopes of Sa. do Espinhaço around Belo Horizonte and Viçosa, N to Grão Mogol, in lat. 16°30'-21°S. — Map 25. — Fl. I-II; fr. ripe VI-X.

For commentary on kinship to A. brachystachya and A. filamentosa see the following discussions of those species.

All but one collection of A. obovata known to us have at most 4 pairs of leaflets in distal pinnae, several not more than 3 pairs, but the blades vary from glabrous or brownish pilosulous dorsally. The exceptional Saint-Hilaire B^/1310 (P), from an unknown locality in Minas Gerais, has up to 6, even 7 pairs, densely pilosulous on the back and ciliate. Provisionally we include this in A. obovata, with which it is otherwise in full agreement.

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.