Monographs Details: Mimosa caliciadenia 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
Synonyms:Mimosa setosa subsp. paludosa (Benth.) Barneby
Description:Species Description - Slender prickly and viscid, diffuse or decumbent shrub or weak treelet with pliant purplish stems to 3 m, these and lf-stks at once stipitate-glandular, finely villosulous in lines, and armed with scattered, antrorsely curved brownish-stramineous aculei to 1-2.5 mm, the glandular setulae ±0.3-0.5 mm tall with cupular orange head 0.2-0.3 mm diam., the facially glabrous lfts thinly setulose- or glandular-ciliolate, the many globose capitula axillary to fully expanded and coevally expanding lvs, until just prior to anthesis conelike and golden-setose. Stipules very early caducous (scarcely known), apparently lance-acuminate ±4x1 mm, pubescent like the adjacent stem. Leaf-stalks slender, distally tapering (3.5-)4.5-l 1.5 cm, the petiole including (or consisting of) livid wrinkled pulvinus 2-12 mm, the longer interpinnal segments 11-21 mm, the first one 0.4—1.1 mm diam., the narrow ventral groove interrupted between most pinna-pairs by a subulate-acicular spicule less than 1 mm; pinnae 4- 6(-7)-jug., accrescent distally, the rachis of longer ones 1.5-5 cm, the longer interfoliolar segments 1-2 mm; lfts of longer pinnae 16-22-jug., the first pair 0.3-1.4 mm distant from subulate paraphyllidia, all in outline linear-oblong obtuse, the longer ones 5.5-8.5 x 1.2-1.8 mm, the plane lustrous blades veinless above, the centric midrib faintly perceptible beneath. Peduncles solitary or geminate, at anthesis subfiliform (2-)2.5-5 cm; capitula without filaments 9-10 mm diam.; bracts spatulate 4-5.5 mm, the blade densely golden- setose dorsally, eglandular, contracted into a slender glabrous claw; flowers 4-merous 8-androus, only a few distal ones bisexual, the rest staminate; calyx campanulate 0.4-0.6 mm, glabrous externally, the rim with a few plain or gland-tipped setulae 0.2-0.4 mm; corolla narrowly funnelform 3.4-4.3 mm glabrous, the lobes 0.8-0.9 mm, at tip thickened and greenish; filaments pink, monadelphous through ±1 mm, exserted to 7-10.5 mm. Pods 1-2 per capitulum, the oblong planocompressed body 20-34 x 7-9 mm, abruptly contracted at base into a stipe 2-2.5 mm and at apex into an erect cusp 5-7 mm, the replum 0.6-0.7 mm wide, shallowly constricted between 3-5 seeds, distantly armed with aculeoli to 0.3-0.5 mm, the livid-purplish or -castaneous lustrous valves not over 0.1-0.15 mm thick in section, low-bullate over each seed and there with a few scattered gland-tipped setulae, when ripe papery, separating from replum and breaking up into broadly elliptic-quadrilateral segments 6-8 mm long; seeds (few seen) compressed-ellipsoid ±5.5 x 3.5 mm, the testa fuscous lustrous.

Distribution and Ecology - In cerrado about rock-outcrops near 900 m, known only from the high e. slope of Sa. do Espinhaço e. of Diamantina, at ± 18°10'S in centr. Minas Gerais, Brazil.—Fl. II-IV(-?). Map 30.

Discussion:

Mimosa caliciadenia may be a local derivative of widespread M. setosa subsp. paludosa, which it resembles in viscid and prickly vesture and in small heads of flowers glabrous except for a few minute setulae on rim of calyx. It differs, however, in relatively few distant pinnae and fewer leaflets (as recounted in the foregoing diagnosis), and in the shorter, but not narrower, therefore proportionately broader, few-seeded, thinly setulose and not viscid-villosulous pod. Mimosa adenocarpa has similar leaf-formula, but smaller leaflets, gland-tipped corollas subtended by minute bracts, pods less than half as wide, and much smaller seeds. The epithet caliciadenia refers to the relatively large stalked cupshaped glands that suggest the stalked mazedium of the lichen Calicium.

It is appropriate to mention here specimens in bud (Irwin 28567. NY) from near S. João da Chapada north of Diamantina, which have the unusually stout capitate-glandular setae of M. caliciadenia combined with the leaf-formula of M. setosa subsp. paludosa, but capitula densely golden-setose prior to anthesis. I have referred them provisionally to M. setosa subsp. paludosa sensu lato, but I suspect that they represent a distinct taxon.

Distribution:Brazil South America| Minas Gerais Brazil South America|