Monographs Details: Mimosa accedens 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 accedens Barneby
Synonyms:Mimosa affinis B.L.Rob.
Description:Species Description - Erect subshrub from xylopodium, the simple stems 4-8 dm x 2-3.5 mm clothed with relatively few, long and narrow multifoliolate lvs, hispid throughout or almost so with fine tapering yellowish setae to 3-9 mm and also villosulous with fine short whitish hairs intermixed with small gland-tipped setulae, the sublustrous lfts facially glabrous but ciliolate and remotely setose around the margin, the subglobose capitula solitary and geminate in lf-axils, the first below or near midstem, rarely a few pseudoracemose and exserted late in season. Stipules erect, narrowly lance- or linear-attenuate 7-13 x 0.6-1.2 mm, ± 5-nerved. Leaf-stalk of lvs near mid-stem 7-16 cm (of some early and some far distal lvs shorter, no further described), the petiole 5-10 mm, the longer interpinnal segments 7-9 mm; interpinnal spicules 0; pinnae (12—) 15-30(-34)-jug., except for shorter proximal ones subequilong, the rachis of longer ones 15-38 mm, the longer interfoliolar segments 1-1.5 mm; lfts of longer pinnae (12-) 14- 26(-38)-jug., the first pair 0.3-1 mm distant from minute subulate paraphyllidia, the blades narrowly oblong obtuse, straight or almost so, the longer ones 2.5-5 x 0.75-1.3(-1.5) mm, the firm blades veinless above, beneath bluntly 2-3- nerved from pulvinule, the centric midrib weakly 1-2-branched below middle. Peduncles (2-)2.5-5.5 cm; capitula without filaments 8-9 mm diam., prior to anthesis moriform but hispidulous; bracts linear-oblanceolate 2-4 x 0.2-0.3 mm, setose-ciliate; flowers 4-merous 8-androus, except for sometimes ciliolate calyx glabrous, the lower ones staminate, the rest bisexual and a little longer; calyx shallowly campanulate 0.5-0.6 mm, obscurely lobulate; corolla turbinate or vase-shaped 3-4.5 mm, the ovate subacute 1-nerved almost plane lobes 1.3-2 mm; filaments pink or fading whitish, monadelphous through ±0.5-0.8 mm, exserted 7-9.5 mm. Pods ascending, 1-2 per capitulum, the stipe 2.5-4 mm, the broadly linear body 60-70 x 9-11 mm, at once setose and glandular-setulose overall, the stout replum 1-1.5 mm wide, the lustrous castaneous, firmly papery valves low-convex over each seed, breaking up when ripe into 9-11 transversely oblong articles 5-7 mm long; seeds ±5 x 3.5 mm, the lustrous smooth testa brown or atrocastaneous.

Distribution and Ecology - On stony campo within the cerrado climax association, 950-1050 m, local about the sources of rios Corumbá and S. Marcos in lat. 15°40'- 17°30'S, Distrito Federal and adj. s.-e. Goiás, Brazil.-Fl. VIII-X; fr. IX-I.

Discussion:

The first collections of M. accedens, namely Burchell 6022 (K) from between Lages and Urutaí and 7507 (K) from between Macacos and Olho d’Agua, dating back to 1828, were mistaken by Bentham for M. setosa. From this M. accedens differs in simple, notably long-setose stems that die back annually to the rootstock, in proportionately long narrow leaves lacking interpinnal spicules, in the mostly lateral and axillary, not pseudoracemose peduncles, and further, from sympatric var. setosa, in the glabrous or only minutely ciliolate calyx. It was recognized as distinct, but never formally described, by Harms from a collection made by Glaziou in early 1895 in the present Federal District. Harms’s epithet affinis being preoccupied in Mimosa, I have substituted accedens, suggested by the apparent affinity to M. setosa.

Distribution:Brazil South America| Goiás Brazil South America| Distrito Federal Brazil South America|

Narratives:Mimosa accedens