Mimosa claussenii

Title

Mimosa claussenii

Authors

Rupert C. Barneby

Scientific Name

Mimosa claussenii Benth.

Description

242. Mimosa claussenii Bentham, J. Bot. (Hooker) 4: 405. 1842.—Typus infra sub var. claussenii indicatur.

Coarse unarmed, amply leafy, potentially arborescent shrubs commonly 1-2.5 m, but at times appearing herbaceous when regenerating from fire, and sometimes truly (or seemingly) acaulescent or with new stems from procumbent branches, exceptionally attaining 3-4 or even 6 m with trunk attaining 5-10 cm diam., the hor- notinous branches usually 8-15 mm diam. and like the axes of lvs and inflorescence densely setose with basally dilated and either incurved-ascending, erect or retrorse, distally tapering of flagelliform stramineous setae to (2.5-)3-10 mm long and at base to (0.2-)0.3-l .2 mm diam. mixed or not with minute villi but only very exceptionally with gland-tipped setulae (the lfts then glandular-ciliolate), the inflorescence a terminal, simple or weakly paniculate-branched pseudoraceme commonly less than 2 dm but exceptionally to 10 dm of globose or ellipsoid capitula subtended by hysteranthous lvs, these rapidly expanding at late anthesis or shortly thereafter and much surpassing the fruits, the multijugate lfts setose- or setulose- and sometimes in addition finely villosulous-ciliolate, glabrous on both faces or sometimes remotely puberulent on either, the pulvinules nearly always densely gray-villosulous. Stipules lanceolate or triangular-acuminate (5—)6—18 x (1.5—)2—5 mm, the coriaceous blade densely setose dorsally, glabrous castaneous within, deciduous or rarely subpersistent. Leaf-stalks of fully expanded lvs commonly 1536 cm, rarely only (6—)9—18 cm or to 60 cm, the stout petiole including obese hard pulvinus (l-)2- 7(-9) cm x (1.7-)2.2-5 mm, the longer interpinnal segments mostly to 0.8-1.5 cm or when relatively few to 2.5-4 cm, the ventral groove continuous between pinna-pairs (spicules 0); pinnae commonly (8-) 10-22-, locally to 24-30(-37)- jug., decrescent proximally, less or not so distally, the rachis of longer ones (3-)4-l 5(—17) cm, the longer interfoliolar segments (1-) 1.4-3.5 mm; lfts of longer pinnae (25-)30-55(-62)-jug., the first pair close to pulvinus (paraphyllidia 0), all in outline linear-oblong obtuse apiculate, straight or slightly incurved distally, the longest (5.5-)7- 13(—15) x (1.2—) 1.5—2.5(—2.8) mm, in var. microphyllidia 3-6 x 0.6-1.2 mm, the blades veinless or almost so above, beneath weakly obtusely 3-5-nerved from pulvinule. Peduncles either solitary or 2-3 per node of inflorescence (2.5-)3- 15(-20) cm; capitula without filaments (11 —) 13—21, rarely 20-25 mm diam., prior to anthesis conelike or comose, the densely villous floral axis becoming 1—3.5(—7) cm; bracts commonly oblanceolate,elliptic-oblanceolate or spatulate (3-)3.5-7.5, exceptionally to 12-15 mm, either longer or a little shorter than the subtended fl, in either case densely setose dorsally from base upward; flowers mostly 4-merous, the lower ones sometimes staminate and 5-merous, all diplostemonous; calyx-tube membranous 0.4-0.7(-1.2) mm, glabrous externally beyond the sometimes setulose pedicel, the irregularly crenate-lobulate rim ciliate with simple setae to (0.5-)0.6-2.1(—2.5) or exceptionally only 0.3-0.4 mm; corollas either subhomomorphic or the lowest ones shorter and proportionately broader than the distal bisexual ones, the longer 4-8 (in vars. claviceps and dolichopoda to 9-10) mm, these narrowly cylindric-vase-shaped, the ovate lobes 1.6-4 mm, always setulose or setulose-barbate dorsally; filaments united below the ovary into a stemonozone 1 mm or less, pink or lilac fading whitish, the longer ones exserted (10-) 13-27 mm. Pods usually several (3-14) per capitulum, sessile, plumply compressed-ellipsoid or oblong-ellipsoid, in profile 2.5-5 x 1.4-2 (locally only 1-1.4) cm, bluntly or obscurely apiculate, the replum (disregarding vesture) 1.5-3.5(-4.5) mm wide, the low-convex valves consisting of livid exocarp at least 0.3-1.7 mm and toward outer margins sometimes to 2.1mm thick and of crustaceous endocarp 0.1-0.25 mm thick, when ripe separating entire from replum, the pod overall concealed by a dense coat of stout erect, distally incurved-ascending stramineous setae to (2-)3-5 (-7) mm; seeds (poorly known) 7-14, often irregularly 2-seriate, ±4.3-5.6 mm, the testa castaneous lustrous.

As defined by the description, M. claussenii is a multiracial complex of which the detailed structure requires close investigation in the field. The classification that follows is more exploratory than definitive.