Monographs Details: Mimosa somnians subsp. somnians var. deminuta
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.
Description:Variety Description - Stems prostrate or assurgent 6-10 dm, freely branched, aculeate like var. somnians and either stipitate-glandular or subglabrous, the ultimate branchlets subfiliform; leaf-stalks of primary lvs 4-7 cm, the petiole 1-2.5 cm, the longer interpinnal segments 6-14 mm; pinnae 4-8-jug., the rachis of longer ones 9-14 mm, the lfts 13-19- jug.; capitula without filaments ±4 mm diam.; stipe of pod 5-17 mm, the body 30-40 x 3-4 mm, 6-8-seeded, glabrous or glandular.

Distribution and Ecology - On and about denuded rock outcrops along the e. bank of río Orinoco from near Puerto Ayacucho downstream to mouth of río Caura, in Amazonas and Bolívar, Venezuela, and near the mouth of río Meta in Vichada, Colombia.—Fl. X-II. Map 39.

Discussion:This ecologically specialized variety differs from var. somnians in abbreviated pinnae and consequently few leaflets. Its slender growth-habit and tiny capitula are nearly matched by one collection (Plowman 9167, mun. Babaçulândia, lat. 6°56'S, NY) from a savanna habitat in northern Goiás, Brazil; but this has to 28 pairs of leaflets in longer pinnae. The known range and habitat of var. deminuta are those of Chamaecrista glandulosa var. crystallina Irwin & Barneby.

A single individual plant (Guánchez 4782, NY), found in a roadbed on lower río Suapure in northwestern state of Bolívar, Venezuela, has extremely diminished foliage with these dimensions not allowed for in the diagnosis of var. deminuta: leaf-formula v-vi/11-14, rachis of distal pinnae only 3-5.5 mm, and longest leaflets only 1.5-2 mm long.

Distribution:Colombia South America| Vichada Colombia South America| Venezuela South America| Bolívar Venezuela South America| Amazonas Venezuela South America|