Mimosa struthionoptera 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 struthionoptera Barneby

  • Type

    246. Mimosa struthionoptera Barneby, sp. nov., e grege Pachycarparum foliolis minutis con- fertissimis ac valde numerosis notatarum his signis eminens: pubes e villis densis nitidis setulisque subaequilongis glandula luteola coronatis intermixtis ±0.3-0.5

  • Synonyms

    Mimosa densa Benth.

  • Description

    Species Description - Amply leafy unarmed tree 4 m, of unknown girth, the stout, densely leafy homotinous branches together with short exserted pseudoraceme of plumply ovoid capitula to 3-3.5 dm, the stems and foliage densely softly gray-villous and viscidulous with erect silvery hairs and yellowish pin-glands ±0.3-0.5 mm intermixed with random (beneath capitula crowded) fine plain rufescent setae to 1-1.5 mm, the lfts villosulous on both faces, glandular-ciliolate. Stipules (early dry caducous, consequently little known) lance-acuminate 9-12 x 1-1.5 mm, the firm blades glabrous castaneous within. Leaf-stalks ascending at narrow angles to the stem, 11-17 cm, the petiole including (or largely composed of) obese gray-velutinous pulvinus 9-12 mm, the longer interpinnal segments 5-7 mm, the ventral groove continuous between pinna-pairs (spicules 0); pinnae 22-24-jug., strongly decrescent proximally but scarcely so distally, the rachis of longer ones 4.5-5 cm, the interfoliolar segments 0.7-1 mm; lfts of longer pinnae 50-58-jug., the first pair not more than 0.3 mm distant from minute villosulous paraphyllidia, all narrowly oblong obtuse, the larger ones ±4-4.5 x 1 mm, the blades veinless above, faintly 3-nerved beneath. Peduncles solitary and geminate 4-5 cm; capitula without filaments ±20 x 14 mm, prior to anthesis loosely conelike; bracts linear-oblanceolate 5-6 mm, both setulose and glandular dorsally, surpassing the flower until full anthesis; flower with calyx shallowly campanulate ±0.4 mm, the orifice ciliolate with weak, sometimes gland-tipped setulae to ±0.8 mm; corolla 5-6 mm, the slenderly funnelform tube externally glabrous, the ovate concave, apically callous and dorsally densely setulose lobes ± 1 mm; filaments pale pink, monadelphous through ± 1 mm, exserted to 11 mm; pod unknown.

    Distribution and Ecology - On rocky slopes at or perhaps above 1200 m, known only from the type-locality on the Tocantins slope of Chapada dos Veadeiros, near 14°S in e.-centr. Goiás, Brazil.—Fl. IX-X(-?).

  • Discussion

    Short soft, partly glandular—and on leaf-pul- vini extremely dense and plush-like—indumentum of the foliage, extended (not rosette-forming) annual branches, relatively long crowded pinnae and tiny imbricate leaflets characterize this visually striking arborescent mimosa. In habit it closely resembles M. rheiptera, which differs in predominantly yellow-setose pubescence and longer peduncles. Field observation of growth-forms and dispersal on and between rock-piles in Tocantins National Park are required before the classification of these and related forms can be worked out. The epithet refers to the leaves, fancifully likened to ostrich plumes.

  • Distribution

    Brazil South America| Goiás Brazil South America|