Monographs Details: Mimosa monacensis 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.
Synonyms:Mimosa poculata Barneby, Mimosa somnians subsp. somnians
Description:Species Description - Subshrubs, apparently functionally herbaceous from woody roostock, the weakly branched, pliantly humifuse, distantly leafy stems armed with weak scattered recurved intemodal aculei ±1-1.5 mm and, together with lf-axes and peduncles, viscid-villosulous with fine short simple hairs mixed with erect gland-tipped setulae ±0.5-1 mm, the foliage bicolored, the plane lfts dull brown above, beneath dull olivaceous paler, glabrous on both faces or some puberulent beneath, all thinly ciliolate, the early peduncles solitary in distal lf-axils but later ones pseudoracemose exserted. Stipules erect, ovate- or lance-acuminate 2—4 x 1-1.8 mm, striately several-nerved, persistent. Leaf-stalks 2.5-4.3 cm, the petiole 2-3.5 cm, at middle 0.4-0.6 mm diam., the one interpinnal segment 5-9 mm; a lance-subulate subherbaceous spicule 0.8-1.3 mm between proximal pair; pinnae exactly 2-jug., the distal pair a little longer, the rachis of these 2.2-3 cm, the longer interfoliolar segments 1.5-2.5 mm; lfts of distal pinnae 11-16-jug., decrescent at each end of rachis, the proximal pair unequal and 1-2.4 mm distant from minute paraphyllidia, all in outline linear-oblong obtuse from obtusangulate base, those near mid-rachis 6.5-9 x 1.5-2 mm, 4-5 times as long as wide, veinless above, beneath pallidly 4-5-nerved from pulvinule, the centric costa 2-3-branched near and beyond midblade. Peduncles 1-2 per node, 14-17 mm; capitula globose, without filaments ±5.5 mm diam., prior to anthesis conelike; bracts ovate 2-2.5 x 1.2-1.5 mm, striately 9-11-nerved, thinly pilosulous, persistent, the lowest ones irregularly connate into an involucroid collar; flowers 4-merous 8-androus; calyx membranous, shallowly campanulate 0.2 mm glabrous; corolla turbinate ±2.5 mm, the firm striate-nerved lobes ±1.3 x 0.8 mm, thinly pilosulous dorsally; filaments eight, not seen complete. Pods one per capitulum erect, the stipe 7-11 mm, the linear, distally attenuate body 3.5-5 x 0.4 cm, 6-10-seeded, the shallowly undulate replum 0.3-0.4 mm wide, the pallid papery valves breaking when ripe into bullately biconvex oblong-elliptic articles 4.5-6 mm long, the replum and valves alike glandular-setulose overall and the valves in addition thinly pilosulous and yellowish-setulose; ripe seeds not seen.
Distribution and Ecology - In unrecorded habitat, but to be expected in cerrado near or above 700 m, known only from the type-locality on the sources of rio Carinhanha, near 15°S in extreme n.-w. comer of Minas Gerais, Brazil.—Fl. VIII-IX.
The description of M. monacensis is prepared from specimens misidentified by Bentham as M. bijuga (Benth., non Veil., now M. poculata), specimens which incidentally provided the fruiting characters assigned to M. bijuga in Flora Brasiliensis. They resemble M. poculata in dilated stipuliform floral bracts, of which the lowest are irregularly fused into an involucral collar; but differ in trailing aculeate stems charged with fine villi and many viscid setules, and in pubescent flowers. The indumentum of mixed prickles, stipitate glands and simple hairs suggests a more direct connection with M. somnians subsp. somnians, but this is normally shrubby prior to anthesis, has (like M. bijuga, despite its epithet) more than two pairs of pinnae in mature cauline leaves, and minute 1- or faintly 3-nerved floral bracts.
The epithet monacensis celebrates the illustrious Bavarian botanists who conceived and contributed to Flora Brasiliensis.
Distribution:Brazil South America
| Minas Gerais Brazil South America