Pithecolobium foliolosum Bentham, London J. Bot. 3: 223. 1844, ex parte, quoad pl. pemambucensem Gardneranam, lectotypo excluso. = Gardner s.n. in May, 1838, e Río Capibara, BM!.

Pithecolobium parvifolium sensu Bentham in Martius, Fl. Bras. 15(2): 454. 1876, ex parte, quoad Spruce 882 (K!, NY!) cum nom. nud. in synonomia Calliandra spruceana Bentham; non P. foliolosum (Swartz) Bentham, quae = Ch. mangense var. mangense.

Pithecolobium acacioides sensu Ducke, 1949: 46.

Broad-crowned drought-deciduous microphyllidious trees 5-30 m with smooth trunk attaining 2-5 dm diam, either randomly armed at nodes with stout tapering, solitary or paired, ascending thorns 4—27 mm or more often unarmed, the stiffly flexuous, densely lenticellate branchlets early glabrate, the lf-axes and peduncles pilosulous with fine, forwardly incurved pallid hairs to 0.15-0.35 mm, the lfts bicolored when mature, paler beneath, at least thinly ciliolate but glabrous facially, the inflorescence of the genus; perulate buds axillary to mature lvs ovoid (1.5-)2-4 mm, the scales dorsally castaneous glabrous, striately nerved, microscopically ciliolate. Stipules often obsolete, when developed either linear or linear-oblanceolate and attaining 12 mm, the submembranous blade finely several-nerved, early caducous. Lf-formula (vi-)vii-x/30-46; lf-stks 4.5-8.5(-l2) cm, the petiole proper 8-24 mm, the longer interpinnal segments 4-8(-l 1) mm; nectary at or shortly below midpetiole sessile, shallowly cupular (0.5-)0.6-1.3(-1.6) mm diam, in profile 0.2-0.5 mm tall, a smaller nectary at tip of lf-stk and yet smaller ones between 1-3 furthest pairs of lfts; rachis of longer pinnae 2.5-4(-6) cm, the longer interfoliolar segments 0.5-0.8(-1.2) mm; lfts subequilong except at very extremities of rachis, at first subvertically imbricate but spreading at maturity, the blades linear from obliquely obtusangulate base, straight or slightly porrect at deltate or triangular acute apex, the larger ones 3-6.5 x 0.5-0.9 mm, 5-7 times as long as wide, the almost centric midrib 1(-2)-branched above midblade, flanked on either side by an intramarginal primary nerve produced almost to blade’s apex, the venation immersed on upper face, finely prominulous and often pallid beneath. Peduncles solitary or geminate 5-16 mm; capitula hemispherical 16-27-fld, the fls dimorphic, the axis of receptacle, including the pedestal of the sessile heteromorphic central fl, 2-3 mm; bracts minute or obsolete; PERIPHERAL FLS: sessile or the lowest raised on pedicel to 0.45 mm; perianth 5-merous, the calyx and corolla greenish, the anthers white at early anthesis, yellowing in age; calyx campanulate 5- nerved 1.3-2 x 0.5-0.7 mm, either glabrous or thinly pilosulous externally, the deltate teeth 0.1-0.25 mm; corolla narrowly trumpet-shaped 3.6-5.4 mm, the lance-ovate lobes 1.2-2 x 0.6-0.8 mm, microscopically papillate on margin; androecium 10-12-merous, 11-14.5 mm long, the filaments united into a tube 1.6-2.4 mm surrounding the glabrous truncate ovary; TERMINAL FL: sessile, the calyx 1.5-1.7 x 1-1.7 mm, the corolla 5.5-6.5 x ±1 mm; androecium of same length as that of peripheral fls but the tube 6-8.5 mm, distally 0.8-1.5 mm diam, fimbriately dissected at orifice, but fertile stamens no more numerous; stigma slightly enlarged, ±0.1 mm diam. Pods usually solitary, subsessile, undulately linear 6-7 mm wide, spirally decurved and coiled through 1.5-4 circles into a compressed helix 1.6-2 cm diam, the sutures ±0.5-0.8 mm wide, the exterior (seminiferous) one sinuously constricted between seeds, the thinly leathery green glabrous venulose valves becoming crustaceous fuscous, bullately extended over each seed, these lying transverse in discrete chambers but not separated by raised septa; dehiscence through both sutures but tardy and irregular, the seeds mostly released by weathering; seeds plumply lentiform, in broad view 3.8-4.5 x 3.6 mm, the testa smooth, pale tan, fuscous over the pleurogram, this nearly complete 2.5-3 x 1.5-1.7 mm.

In seasonally dry tropical woodlands and at edge of campo or on river terraces, in Pará going out to sands of the coast, below 200 m, discontinuously widespread in NE Brazil and French Guiana: in Brazil, from the lower Amazon valley in Amapá and Pará upstream to the mouth of Río Trombetas, S along the Tocantins-Araguaia to near 11 °S in the NE comer of Mato Grosso and adjoining Goiás, E through Maranhão and N Ceará to E Pernambuco, in French Guiana along and near the coast from Cayenne W to the mouth of the Marowijne, to be sought in adjacent Surinam; occasionally cultivated elsewhere (Medellín, Colombia, Duque 1834, US; Rio de Janeiro, Brazil, H. M. Curran 357, US). — Map 39. — Fl. VI, IX-XII, simultaneously with flush of new foliage. — Jurema, jurema branca, pereira.

Ducke described Ch. acacioides as a spiny tree of low or median stature with broad umbrella-shaped crown, resembling some African acacias and like them leafless in the dry season. The small, tightly spiral pod recalls that of Enterolobium schomburgkii in form, but is of thinner texture.