Monographs Details: Mimosa oedoclada 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 manidea Barneby
Description:Species Description - Unarmed pachycaul rosette-trees or arborescent shrubs at anthesis 1.5-5 m, with blackish trunk attaining 18 cm diam. and few, awkwardly ascending leafless candelabriform branches 6-15 mm diam. marked by transverse lf-scars, the current lvs and short terminal pseudoraceme of globose yellow-setulose capitula crowded at tip of branchlets, the lf-axes and peduncles hispid with yellowish attenuate setae to 2-5 mm long and 0.2-0.3 mm diam. at swollen base, mixed with fine short villi and fine setulae capped with an orange viscid head, the many small lfts finely villosulous beneath or on both faces, ciliolate. Stipules early reflexed, broadly lance- or triangular-acuminate 6-11 x 2.5-5.5 mm, internally glabrous castaneous (exceptionally thinly setose), externally orange-glandular, setose-ciliate, deciduous with associated lf. Leaf-stalks 4.5-10 cm, the petiole including stout livid pulvinus 5-10 mm, near first pinna-pair 1.5-2 mm diam., the longer interpinnal segments 4-8 mm, spicules 0; pinnae 8-15-jug., strongly decrescent proximally, otherwise subequilong, the rachis of longer ones 25-35 mm, the first pair of lfts next to pulvinus or rarely degraded to minute paraphyllidia, the longer interfoliolar segments 1-1.5 mm; lfts of longer pinnae 14-20-jug., in outline ovate-oblong or oblong, obtuse or subapiculate, the longer ones 4-6 x 1.5-2.2 mm, the firm blades ciliolate with a few longer tapering or shorter gland-tipped setulae, low-venulose on each face, the centric midrib and two intramarginal nerves united by several obliquely ascending secondary venules. Peduncles 3-7(-9) cm; capitula squatly ovoid or globose, without filaments 12-17 mm diam., prior to anthesis moriform; bracts firm castaneous, broadly oblanceolate 4-5.5 x 1-2.2 mm, beyond middle setose and stipitate-glandular, pectinately setose-ciliate; flowers 4-merous 8-androus, mostly staminate, the few bisexual ones a little longer; calyx membranous campanulate, externally glabrous, 0.55-1.1 mm, the subtruncate rim delicately few-ciliolate; corolla 5-7 mm, the narrowly funnelform tube glabrous, the ovate 1-nerved lobes 1.1-1.5 mm, distally finely pilosulous or minutely glandular; filaments lavender-pink, monadelphous through ± 1 mm, exserted 14-17 mm. Pods 1-several per capitulum, firmly attached to receptacle and persistent for nearly a full year, in profile broadly elliptic, apiculate by stout cusp ± 1 mm, 25-40 x 12-16 mm, (3-)4-6-seeded, the replum 3-3.5 mm wide, the fleshy, when ripe stiffly leathery low-convex valves falling entire from replum, this and valves alike densely setose and glandular-setulose overall; seeds unknown.
Distribution and Ecology - On rocky stream-banks in cerrado and about rock piles in campo rupestre, 1000-1400 m, colonial and locally plentiful on Chapada dos Veadeiros within ±40 km n. and n.-w. of Alto Paraíso in lat. 13°30'-14°10'S, e.-centr. Goiás, Brazil.-Fl. X-III; fr. XH-onward.
Among the several potentially arborescent Pachycarpae of candelabriform habit native to Chapada dos Veadeiros M. oedoclada is notable for exceptionally thick branchlets (mostly 6-12 mm diam., whence the epithet), an indumentum composed in part of gland-tipped setulae and consequently clammy foliage, and relatively few and short pinna-pairs. In many respects it resembles and seems akin to sympatric M. manidea, but differs substantially in these characters: stipules deciduous with associated leaf, the blade usually glabrous within and viscid-glandular without, ordinarily early reflexed; pinnae 8-15 pairs; indumentum of leaf-axes composed of simple setae to 0.2-0.3 mm diam. at base, fine villi, and orange gland-tipped setulae; larger leaflets 4-6 x 1.5-2.2 mm. By contrast the stipules of M. manidea persist a full year after fall of the associated leaf, the erect blades, setose both within and without, forming an imbricated thatch on the annotinous branchlets; pinnae of larger leaves are 18-30 pairs; indumentum of leaf-axes consists of stouter, partly confluent, seemingly branched setae to 2-6 mm long and 0.4-0.7 mm in diam. at base mixed with short claviform but non-excretory setulae; and the larger leaflets are only 2.5-3.5 x 0.8-1.2 mm.
Distribution:Brazil South America
| Goiás Brazil South America