Mimosa guatemalensis

  • Title

    Mimosa guatemalensis

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa guatemalensis (Hook. & Arn.) Benth.

  • Description

    26. Mimosa guatemalensis (Hooker & Amott) Bentham, Bot. voy. Sulphur 89. 1844, based on Inga (?) guatemalensis Hooker & Amott, Bot. Beechey Voy. 419. 1841.—"Realejo . . . N. Lat. 12°45'. . . Guatemala [now Nicaragua, but the plant in reality collected most probably at Tepic, Nayarit, Mexico]."—Holotypus, Sinclair s.n., s. loc., K (hb. Hook.)! = MICH Neg. 613; presumed isotypi, labelled "Tepic, Barclay," K (hb. Hook., hb. Benth.)!— Acacia (sphalm.) guatemalensis Bentham, 1875: 414 (in syn.), 647.

    Stiffly branched shrub attaining 1.5(-?) m, randomly armed on intemodes with 2 infrastipular and 1, often distantly displaced, infrapetiolar, nearly straight, horizontal broad-based aculei 28 mm, silky-pilosulous or -tomentulose throughout with fine loose lustrous hairs to ±0.2-0.3 mm, the pale green, marginally revolute lfts pubescent on both faces but paler and more densely subvelutinous beneath, the inflorescence a proximally leafy-bracteate, distally efoliate, simple pseudoraceme of verticillate amentiform spikes 1.5-5 dm above foliage. Stipules erect, ovate or lanceolate 2.5-5.5 x 0.7-2.5 mm, becoming dry pallid, either bluntly 1-nerved dorsally or obscurely nerved. Leaf-formula (ii-)iii-vi/(3-)4-7, the lf-stks 3-7 cm, either unarmed or randomly aculeolate, the petiole and longer interpinnal segments ±1-2.5 cm, the ventral sulcus bridged between pinna-pairs and charged there with a pallid spicule 0.7-2 mm; pinnae accrescent distally, the rachis (sometimes minutely spiculate between lfts) of longer ones 2-5 cm; lfts ovate, elliptic or elliptic-obovate, abmptly minutely apiculate, the longer ones (7-) 10-20 x (3—)5—12 mm, 1.6-2.1 times as long as wide, all veinless or weakly pallid-veined above, prominulously 2-3(-4)-nerved beneath, the slightly excentric midrib pinnately 2-6-branched on each side, the inner posterior nerve weakly brochidodrome either below or beyond mid-blade, a fine tertiary venulation developed or not. Flower-spikes (1—)2—5 per node of pseudoraceme, without filaments 5-6 mm diam., the pliant axis, including peduncle, 6-13.5 cm, the linear bracts 1-1.6 mm, early caducous, the obovoid fl-buds densely pallid-sericeous; flowers sessile (4-)5-merous diplostemonous, all bisexual; calyx membranous campanulate, externally silky-velutinous 1.5-1.9 mm, the deltate teeth 0.2-0.5 mm; corolla campanulate-vaseshaped 2.4-3.5 mm, the erect lobes 1-1.4 x 0.65-0.8 mm; filaments pink, very shortly united below ovary, exserted 4-6.5 mm. Pods ±1-5 per spike, sessile or narrowed at base into a stipelike neck to 4 mm, in profile linear, gently or falcately curved, 35-50 x 5-6.5 mm, 5-8-seeded, the almost straight, unarmed or randomly few-aculeolate replum 0.5-0.8 mm wide, the valves bullately elevated over each seed, the valves and replum alike densely silky-velutinous overall, the valves breaking up into free-falling articles 4.5-6.5mm long.

    In shrub thickets, subdeciduous woodland and open oak-woodland, sometimes in roadside hedges, ranging from ±200 m in the Pacific foothills to 1700 m in the Balsas Basin, discontinuously dispersed in tropical w. Mexico from Sinaloa (n. of Copala) and Nayarit e. through Guerrero and Michoacán to s.-e. Mexico.—Fl. X-II.