Monographs Details: Mimosa diptera Barneby
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 diptera Barneby
Description:Species Description - Slender, remotely leafy, essentially glabrous unarmed herb 9-15 dm, the 5-angular stems erect from a carrot-shaped xylopodium, strictly few-branched from either below or from beyond middle, at widest point 1.5-2.5 mm diam. and internally pithy, the inflorescence a narrow, weakly branched efoliate panicle of very small remote, globose moriform capitula. Stipules lance-ovate 1-2 mm, atrocastaneous, dorsally 1-nerved, tardily deciduous. Primary cauline leaves separated by internodes 6-18 cm, their capillary petiole 3-6 cm, at middle 0.2-0.3 mm diam., bearing at apex a deltate-apiculate spicule 0.4-0.7 mm in front of the microscopically puberulent pinna-pulvini; pinnae 1 -jug., the slender tapering rachis (2-)2.5-4.7 cm, the interfoliolar segments 1-1.7 mm; lfts (12-) 15-23-jug., the small first pair 1-1.5 mm distant from subulate livid paraphyllidia, the blades narrowly oblong, obscurely curved forward, 3-6.5 x 0.7-1.8 mm, all faintly 2-nerved from pulvinule, the costa only slightly displaced from center. Peduncles capillary 8-12 mm; capitula less than 20-fld, without filaments 3-4 mm diam.; bracts obovate-oblanceolate 0.7-1 mm, minutely denticulate; flowers 4-merous 8-androus glabrous; calyx 0.4-0.8 mm, shallowly 4-denticulate; corolla turbinate 1.7-2.8 mm, the ovate membranous 1-nerved lobes 0.9-1.5 mm; filaments pink, monadelphous through ±0.1 mm, exserted 2.5-3.5 mm. Pods 1-3 per capitulum, stipitate, the stipe 3.5-4.5 mm, the broadly linear, planocompressed body 30-55 x 5-6 mm, 3-12-seeded, the smooth straight or undulately constricted replum 0.4-0.5 mm wide, the smooth, stiffly papery, purplish-castaneous valves low-colliculate over each seed, when ripe breaking up into many almost square or fewer elliptic, free-falling articles', ripe seeds not seen.

Distribution and Ecology - On sandstone outcrops at ±650-700 m, apparently local, known only from Chapada dos Guimarães and Sa. S. Lourenço in s.-centr. Mato Grosso and from Sa. do Caiapó in adj. s.-w. Goiás, lat. 15°20'-17°30'S, Brazil.-Fl. I-III. Map 18.

Discussion:

Mimosa diptera is amply distinct from all other unarmed Paucifoliatae in the solitary pair of pinnae consisting of numerous (12-23) pairs of small crowded leaflets. The tall slender, remotely few-leaved stem and the relatively long stipe of the pod are equally distinctive in the series.

Distribution:Brazil South America| Goiás Brazil South America| Mato Grosso Brazil South America|

Narratives:Mimosa diptera