Mimosa decorticans

  • Title

    Mimosa decorticans

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa decorticans Barneby

  • Description

    249. Mimosa decorticans Barneby, sp. nov., cum M. setosissima et M. densa manifeste affinibus sed allopatricis habitu toto, foliorum forma et praesertim ramulis annotinis epidermide exfoliata nudis cinnamomeis comparanda, ab ea pube setosa breviori, foliolis minoribus 2-3.5 (nec 3.5-5) mm usque longis, calycis ore ciliolato (nec nudo) necnon legumine longiori 4.5-6 (nec 2.5-3.5) cm long, ab hac pinnarum majorum rachi breviori 16-25 (nec 23-43) mm usque longa, foliolis 25-31 (nec 30-47)-jugis usque, corollaque breviori ±3.5-3.8 (nec 55.5) mm longa diversa.—Brazil. Goiás: rod. BR-7, km 620, Cristalina, 27.III.1973 (fl + fr vet), Edmundo Pereira 7341. —Holotypus, BRADE 27057; isotypus, NY.

    Amply leafy microphyllidious arborescent shrubs and treelets 2-3.5 m with trunk attaining 1 dm diam., the epidermis of branchlets exfoliating with fall of lvs, the new foliage crowded at tip of homotinous branchlets on a framework of naked cinnamon-brown older ones, the axis of young stems, lvs and peduncles strigose with fine tapering appressed-ascending setae to ±1—1.5 mm commonly mixed with minute villi or subsessile glands or both, the tiny crowded lfts either glabrous or puberulent above, commonly puberulent beneath, finely setulose-ciliolate, the inflorescence a compact, scarcely or shortly exserted pseudoraceme of conelike globose or squatly ovoid-ellipsoid capitula, the pods axillary. Stipules caducous (little known), lance- or ovate-acuminate ±4-6 x 1.5-3 mm, internally glabrous castaneous. Leaf-stalks 6-16 cm, the petiole together with or reduced to the obese pulvinus 2.5-6 mm, the longer interpinnal segments 2-6(-6.5) mm, the ventral groove concealed by setae but continuous between pinna-pairs (spicules 0); pinnae (15-) 17-28-jug., strongly decrescent proximally and a little so distally, the rachis of longer ones 23—43 mm, the longer interfoliolar segments 0.4-0.9 mm; lfts of longer pinnae 30-47-jug., the first pair directly next to pulvinus (paraphyllidia 0), all in outline narrowly oblong, linear, or (when very short) oblong-elliptic, obtuse or apiculate, smooth veinless above, weakly 1-2-nerved beneath. Peduncles 2.5-5 cm; capitula without filaments 10-12 mm diam.; bracts oblanceolate mostly 5-6.5 x 0.9-1.5 mm, the lowest sometimes shorter, all setulose and usually glandular dorsally; flowers 4-merous 8-androus, some lower ones staminate; calyx 0.6-1 mm, the undulately truncate rim with few plain or gland-tipped setulae to 0.3-0.5 mm; corolla 3-5.5 mm, the narrowly funnelform tube glabrous, the ovate lobes 1-1.3 mm, 1-nerved, densely minutely setulose externally; filaments pink fading whitish, monadelphous through ± 1 mm, exserted to 9-15 mm. Pods ±2-4 per capitulum, sessile, when well fertilized broadly linear in profile 45-60 x 11-13 mm, the replum 1-2 mm wide, the low-convex valves shallowly depressed between the 8-11 seeds, the livid exocarp 0.05-0.1 mm and the papery-crustaceous endocarp 0.1-0.2 mm thick in section, the replum and valves alike densely strigose-hispid with forwardly subappressed-ascending setae to 1-1.5 mm mixed with shorter gland-tipped setulae, the ripe valves separating entire from all but very base of replum, recurved from apex to release the seeds, these not seen.

    About sandstone outcrops in campo, ±12001250 m, endemic to the heights of Sa. dos Cristais within a radius of ± 10 km of Cristalina, near 16°45'S in s.-e. Goiás.-Fl. III-IV.

    Very closely related to M. densa, M. heringeri, and M. setosissima, which see for comment.