Mimosa ophthalmocentra Mart.

  • Authors

    Rupert C. Barneby

  • Authority

    Barneby, Rupert C. 1991. Sensitivae Censitae. A description of the genus Mimosa Linnaeus (Mimosaceae) in the New World. Mem. New York Bot. Gard. 65: 1-835.

  • Family

    Mimosaceae

  • Scientific Name

    Mimosa ophthalmocentra Mart.

  • Type

    65. Mimosa ophthalmocentra Martius ex Bentham, Trans. Linn. Soc. London 30: 415. 1875. —"Brazil, prov. Bahia.", the locality particularized in Martius, Fl. bras 15(2): 359. 1876. ". . . in silvis Catingas ad Villa Nova da Rainha provinciae Bahiensis et in

  • Synonyms

    Mimosa acutistipula (Mart.) Benth.

  • Description

    Species Description - Trees attaining 4-6 or reportedly 12 m with several trunks to 1-2 dm diam., the livid branches either unarmed or erratically armed with broad-based horizontal or gently curved infrastipular aculei 1-12 mm, the homotinous branchlets and axes of lvs and inflorescence glandular-puberulent with fine erect simple hairs and at least a few gland-tipped ones not over 0.2 mm, the olivaceous subconcolorous lfts facially glabrous eglandular, usually minutely ciliolate, the fl-spikes either all axillary to expanded lvs or some distal ones forming a small panicle or pseudoraceme exserted up to 1 dm from foliage. Stipules firm, narrowly lanceolate ± involute (2.5-)3-8 x 0.4-0.9 mm, bluntly carinate dorsally, puberulent on both faces, tardily deciduous. Leafstalks 1.5-4.5(-6) cm, the petiole including livid pulvinus 2-6(-9) x 0.5-0-1.2 mm, the longer interpinnal segments (2.5-)3-10 mm, the ventral groove interrupted between all but the first pair of pinnae by a bridge and small spicule; pinnae 2-6-, commonly 2-4-jug., accrescent distally, the axis of longer ones (1-) 1.3-4 cm, the longer interfoliolar segments 0.6-1.8(-2) mm; lfts of longer pinnae (14—) 15-21(-24)-jug., decrescent proximally but elsewhere subequilong, the blades in outline oblong or linear-oblong obtuse or acute, straight or gently curved forward, the longer ones 4-7 x 1.2-2 mm, 3-6 times as long as wide, all delicately 2(-3)-nerved from pulvinule dorsally, the displaced midrib dividing the blade 1:2-3.5 and giving rise on posterior side to 2-3 weak secondary venules, the venation sometimes visible above but fully immersed. Axes of flower- spikes including short peduncle (2-)3-7 cm; bracts linear-oblanceolate or -attenuate 0.7-1.3 x 0.15-0.25 mm; fl-buds oblong-obovoid 4-angulate; flowers 4-merous 8-androus, mostly bisexual; calyx 0.65-0.9 mm, either puberulent externally or merely ciliolate, the widely deltate teeth 0.1-0.25 mm; corolla white or pink-tinged, narrowly campanulate 1.5-2.6 mm, glabrous or at times papillate at tip of erect, apically incurved lobes, these 0.5-0.9 x 0.5-0.8 mm, carinate by the prominent midrib; filaments white or creamy-white, free, the longer ones exserted 4-4.5 mm; ovary glabrous. Pod sessile, (Lewis, 1987, fig. 8L) broadly linear planocompressed, when well fertilized (35-)40-70(-76) x 7-8.5 mm, the almost straight replum 0.4-0.6 mm wide, sometimes microscopically puberulent, the papery lustrous valves ±0.1 mm thick in section, at first greenish or reddish, when ripe stramineous or livid, remotely minutely granular, scarcely elevated over seeds, finally breaking up into 7—10(—11) oblong or almost square segments (3-)4-7 mm long; seeds (little known) strongly compressed, in profile rhombic-elliptic ±4.5-5 x 3-4 mm, the fuscous-olivaceous testa moderately lustrous, the areole ± half as long as seed-face.

    Distribution and Ecology - In caatinga woodland, sometimes in low places wet or inundated in the rainy season, surviving disturbance and sometimes forming roadside thickets, mostly between 300 and 600 m, interruptedly widespread and locally abundant in e. Brazil, from interior s. Rio Grande do Norte (near 6°30'S), s. to the Contas valley in Bahia (near 14°30'S) and ascending the S. Francisco valley to rio Cocos (near 13°S); planted in Distrito Federal.—Fl. I-VI(-VIII), the fls sometimes coeval with pods of preceding season. Map 10.

  • Discussion

    Mimosa ophthalmocentra and M. acutistipula are sympatric over much of the former’s range, both are white-flowered and eglandular, and in consequence they have been much, but needlessly, confused in herbaria. At anthesis the tetragonal, narrowly campanulate corolla with erect, apically hooded and dorsally keeled lobes, and, later on, the sessile pod infallibly distinguish M. ophthalmocentra. While M. ophthalmocentra tends to have fewer pairs of pinnae and fewer leaflets per pinna, the leaf-formulae overlap and do not provide reliable criteria.

    Typification of M. ophthalmocentra proved unexpectedly difficult. Five Martius specimens, variably labelled and numbered, are preserved at Munich, all annotated as M. ophthalmocentra in Bentham’s hand. These appear to represent three collections at least, and two species, of which my analysis seems worth recording:

    No. 414, labelled "Vila nova da Rainha," herein proposed as lectotype, is unarmed, has good flowers, and a young pod.

    No. 538 = F Neg. 6192, is so similar to the last that I suspect it to be an isotype, but it is labelled "Piauhy in pascuis."

    No. 564, armed and sterile, labelled simply "Bahia," is of ambiguous identity but very likely M. acutistipula.

    Nos. 536 and 537, both from Piauí, armed and flowering but without pods, have the short leaves of M. ophthalmocentra but the broadly turbinate flowers without prominent ribs that are the trademark of M. acutistipula.

  • Distribution

    Brazil South America| Distrito Federal Brazil South America| Rio Grande do Norte Brazil South America| Bahia Brazil South America|