Mimosa interrupta

Title

Mimosa interrupta

Author(s)

Rupert C. Barneby

Scientific Name

Mimosa interrupta Benth.

Description

72. Mimosa interrupta Bentham, J. Bot. (Hooker) 4: 392. 1841.—"Brazil, Pohl.", the locality particularized in Martius, Fl. bras. 15(2): 358, t. 88 (incorrectly depicting a glabrous ovary). 1876; "in Brasilia interiore ad ‘Buriti pigmeno Guarda Mor’ [=Buriti Grande-Guarda Mor, near 16°S, 15°W in s.-centr. Goiás]."—Holotypus, Pohl d.2458 = 1437, K (hb. Benth.)! = NY Neg. 1859; isotypi, F! = F neg. 54888, K (hb. Hook.)! NY! W!

M. interrupta sensu Bentham, 1876: 415; Malme, 1931: 51, fig. a.

Amply leafy arborescent shrubs and trees, flowering when 1.5-2 m but attaining 4 m with trunk to 7(-?) cm diam., armed at most nodes by a pair of stout broad-based infrastipular aculei 1.5-4.5 mm, the fuscous-livid homotinous branchlets, lf-stks and axes of inflorescence weakly pilosulous with erect whitish hairs to 0.15-0.4 mm, the foliage ± resinous, the bicolored, glabrous or microscopically ciliolate firm-textured lfts brownish lustrous above, paler and minutely punctulate beneath, the extended pseudoraceme of loose fl-spikes exserted at anthesis 1-3 dm above foliage but hysteranthously leafy, the long-persistent pods immersed in lvs. Stipules firm triangular-subulate or lanceolate 1.2-2.5 mm, obscurely 1-nerved, tardily deciduous. Leaf-stalks 5-11 cm, the petiole including firm livid pulvinus 8-16 mm, the longer interpinnal segments 6-15 mm, the ventral groove interrupted between all pairs of pinnae by a stout puberulent spicule 0.7-1.5 mm; pinnae (5-)6- 10(—13) pairs, a little decrescent proximally, the rachis of longer ones 5-6 cm, the longer interfoliolar segments 2-3.3 mm; lfts of longer pinnae 17-26(-31)-jug., the first pair 1-1.5 mm distant from subulate paraphyllidia, the blades linear-oblong or oblong-elliptic obtuse but bluntly apiculate, the longer ones including the obtuse basal auricle (6-)6.5-9.5 x (1.1-) 1.3-3 mm, all when narrow 1-, when broader 2-nerved dorsally from pulvinule, the venation faintly impressed above, an obscure tertiary venulation sometimes visible dorsally. Axis of flower-spikes 7-14 cm; bracts minute caducous; fl-buds plumply ovoid glabrous resinous; flowers 4-merous 8-androus, some functionally staminate; calyx crateriform or shallowly campanulate 0.3-0.4 mm, the rim minutely denticulate; corolla white, broadly turbinate 2-2.8 mm, the ovate 1-nerved, apically callous lobes 1.6-2 x 0.7-1.2 mm, externally minutely glandular-papillate and usually resinously lustrous; filaments white, free, the longer ones exserted 5-7 mm; ovary white-pilosulous, the hairs early deciduous. Pods ascending, sessile or cuneately contracted at base into a stout stipe to 2 mm, the body in profile broad-linear planocompressed, when well fertilized 55-100 x 812 mm, 7-10-seeded, the replum 1.2-1.7 mm wide, the stiff valves composed of livid exocarp ±0.1 mm and crustaceous endocarp 0.1-0.15 mm thick in cross-section, when ripe separating from replum and tardily breaking up into articles 7— 10 mm long, these resinous becoming furfuraceous externally, light brown within; seeds (few seen) ±4.5-5 x 4 mm, the pale brown testa smooth lustrous.

In cerrado and at margin of gallery woodland, 400-700 m, apparently local in s. and e. Mato Grosso do Norte, from mun. Cuiabá to Sa. do Roncador, and in s.-w. Goiás in foothills of Sas. Dourada and Caiapó, n. to the middle Tocantins valley near Carolina, Maranhão.—Fl. XII-III.— Angiquinho. Map 11.

Among the Leiocarpae with dorsally gland- punctate leaflets M. interrupta is notable for ample foliage, lustrously resinous white flowers, and firm planocompressed pod at first resinous but in full maturity finely furfuraceous.