Mimosa oligophylla

  • Title

    Mimosa oligophylla

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa oligophylla Micheli

  • Description

    337. Mimosa oligophylla M. Micheli, Mem. Soc. Phys. Geneve 28(7): 56, pl. 21. 1883.-"[Paraguay.] In pratis humidis, Yag[u]aron, [Balansa] n. 1459; Itape n. 1831; Arroyos y esteros, n. 1831a; Cerro-Peron pr. Paraguari, n. 1465."—Lectotypus, Balansa 1459, G! = NY Neg. 11834.— N.B. syntypus Balansa 1465 = M. pseudopetiolaris.

    Slender erect unarmed herbs 6-14 dm from fusiform root and shortly branched caudex, the solitary or few, simple wandlike stems bearing below or to middle ± 3-6 developed lvs, thence passing into a long narrow efoliate pseudoraceme or few-branched panicle of solitary or mostly geminate, plumply ovoid capitula, the stems, lf- axes and inflorescence strigose with straight, strictly appressed tapering setae to 1-2.5 mm, the olivaceous lfts subconcolorous, the coriaceous lfts glabrous, coarsely pallid-venulose dorsally and setose-marginate, the axis of inflorescence rising 3-9 dm beyond furthest developed lf, the capitula maturing in acropetal sequence. Stipules erect, lance-acuminate 2.5-9 x 1-2 mm, glabrous dorsally, thinly setose-ciliate, prominently 7-9-nerved, persistent. Leaf-stalks 1.54.5 cm, at middle 0.6-1.3 mm diam., the shallow open ventral sulcus terminating in an interpinnal spicule 1-2.5 mm; lfts 28-45-jug., subequilong except at base of rachis, the small first pair 1-1.5 mm distant from subulate paraphyllidia 0.5-1.7 mm, the blades semi-ovate from deeply semicordate base, deltately acute, the longer ones 6-13 x 2-4.5 mm, 2.2-3 times as long as wide, all veinless or almost so above, beneath 4-5- nerved from pulvinule, the stout, continuously prominent midrib displaced to divide blade 1:-2-3, the inner posterior nerve expiring near or beyond mid-blade, the 2 outer posterior and sometimes one weak anterior nerve much shorter, the marginal setae 0.2-0.4 mm diam. in dorsal view, appearing much narrower ventrally. Peduncles 6-12 mm; capitula without filaments 9-10 x 7-8 mm, the fl-buds prior to anthesis nearly or quite concealed by pectinately ciliate emergent bracts, these lance-acuminate ±4 mm, at and below middle scarious and ±0.6 mm wide, pectinately setose-ciliate, the tips attenuate, strongly 1-nerved, more shortly ciholate; flowers 4-merous 4-androus, some lower ones staminate; calyx-tube membranous 0.3-0.4 mm, the subentire rim with fine setulae to 0.3-0.4 mm; corollas narrowly funnelform 2.8-3 mm, the narrowly ovate, shallowly concave, dorsally 1-nerved lobes 0.9 x 0.5 mm, at very tip microscopically puberulent externally; filaments pink, free to base, exserted 7-8.5 mm. Pods usually several per capitulum, sessile, in profile narrowly oblong (6.5—)9—15 x 3-4.5 mm, (l-)2-4-seeded, the shallowly constricted, forwardly setulose replum ±0.3 mm diam., the papery valves more densely hispid with fine setae, when ripe disjointing into free-falling articles ±4-5(when solitary -6) mm long.

    In wet campo near 200-300(?) m, apparently local on the Paraguayan Plateau within 25°30- 26°30'S, 55°30'-57°30'W, from depto. Paraguari (Cordillera de Altos, Yaguarón) w. to depto. Caa- zapá (Tapytá).—Fl. IX-III(-?).