Monographs Details: Mimosa dominarum 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 dominarum Barneby
Synonyms:Mimosa polydema Harms ex Glaz.
Description:Species Description - Amply leafy unarmed pachycaul rosette-treelets 2-3 m tall, with castaneous annotinous branches to 1 cm diam., the epidermis exfoliating with falling lvs, the axes of homotinous stems, lf-stks and inflorescence densely hispid, viscid and villosulous with fine horizontal lutescent plain setae to 4-5.5 mm, spreading gland-tipped setae 1-3 mm, and minute whitish villi, the facially glabrous lfts thinly villosulous- and setulose-ciliolate, the pseudoracemose inflorescence exserted ±2.5-3 dm from lvs but some peduncles subtended by a hysteranthous lf that probably greatly surpasses the fruits. Stipules firm, triangular- or lance-acuminate 8-13 x 2-4 mm, castaneous glabrous within, deciduous before the associated lf. Leaf-stalks 16-21 cm, the petiole including hard obese pulvinus 1-3 cm, the longer interpinnal segments ±10-17 mm; a subulate setulose spicule to 3 mm between each pair of pinnae; pinnae (10-) 18-26-jug., gently decrescent basipetally, the rachis of longer ones 3.5-7 cm, the longer interfoliolar segments 1-1.5 mm; lfts of longer pinnae 3 8-48-jug., subequilong except at each end of rachis, the first pair represented by minute paraphyllidia (often concealed by setae), the blades oblong obtuse apiculate, the larger ones ±4-7 x 1-1.6 mm, all smooth or almost so above, indistinctly 3-nerved beneath. Peduncles 1-3 per node of inflorescence, 3.5-5.5 cm; capitula globose or plumply ellipsoid, without filaments 14-16 mm diam., prior to anthesis conelike; bracts oblanceolate acute 4.5-6 x 0.8-1.5 mm, dorsally from middle upward densely setose and glandular-setulose; flowers 4-merous 8-androus, the lower ones staminate; calyx 0.6-0.85 mm, externally glabrous, the truncate orifice ciliolate with few minute gland-tipped setulae; corolla 5.5-7.2 mm, the narrowly funnelform tube glabrous, the ovate acute lobes 1.3-1.5 mm, from middle upward dorsally setulose; filaments pink fading whitish, monadelphous through ±1.5 mm, exserted 16-21 mm; pod unknown.

Distribution and Ecology - In cerrado or campo rupestre between 1050 and 1500 m, said to be locally plentiful on Chapada dos Veadeiros between 14° and 14°30'S in e.-centr. Goiás, Brazil, and once collected on rio Ponte Alta in the s.-w. comer of Distrito Federal.-Fl. (X-)XI-III.

Discussion:

Mimosa dominarum is the only arborescent pachycaul member of its group that has a spicule between each pair of pinnae, and is remarkable in the same context for a vesture of fine long plain setae of a dull yellowish hue mixed with many extremely long-stalked gland-tipped setae and fine white villi. It differs from habitally similar M. oedoclada and M. manidea in leafstalks about twice as long and in the extended axis of the inflorescence, which rises at early anthesis about 3 dm above the older leaves; and from M. pycnocoma further in relatively long flowers and consequently broad capitula.

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

Narratives:Mimosa dominarum