Senna skinneri

  • Title

    Senna skinneri

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna skinneri (Benth.) H.S.Irwin & Barneby

  • Description

    55.  Senna skinneri (Bentham) Irwin & Barneby, comb. nov. Cassia skinneri Bentham, Trans. Linn. Soc. London 27: 542. 1871.—"Guatemala, Skinner—Holotypus, CGE (hb. Lindl.)! = NY Neg. 9690.—Phragmo- cassia skinneri (Bentham) Britton & Rose, N. Amer. Fl. 23(4): 245. 1930.

    Cassia nelsonii Rose, Contrib. U.S. Nat. Herb. 5: 135, fig. 1. 1897.—"Collected by E. W. Nelson between San Geronimo and La Venta, State of Oaxaca, July 13, 1895 (No. 2783) and also along road from Ocuilapa to Tuxtla, State of Chiapas . . . August 29, 1895 (No. 3069); also by Mr. C. G. Pringle . . . near Cuernavaca . . . (no. 6340)."—Lectoholotypus, Nelson 2783, US! paratypi, Nelson 3069, US! Pringle 6340, NY, US!—Equated with C. skinneri by Standley, 1922, p. 408.

    Cassia trichoneura T. S. Brandegee, Univ. Calif. Pub. Bot. 6: 179. 1915.—". . . near San Geronimo, Oaxaca. [C. A. Purpus] No. 7153 . . —Holotypus, UC 17075! isotypi, F, MO, NY!—Equated with C. skinneri by Standley, 1922, l.c.

    Peiranisia falconiensis Pittier, Bol. Soc. Venezol. Ci. Nat. 10: 110. 1945.—"Falcon: entre Coro y Alta Gracia; flores Mayo 1, 1917 ([H. M.] Curran & [M.] Haman 740, tipo.)"—Holotypus, VEN 36011 = NY Neg. 6326.—isotypi, GH! and numbered 740 but dated 24.IV, US!

    Cassia skinneri sensu Standley, 1922, p. 408.

    Potentially arborescent shrubs, at anthesis (1 -) 1.5-7(- 10) m, with tortuous glabrate, brown, castaneous or nigrescent, prominently lenticellate older and densely pubescent younger branchlets, the latter with lf-stalks, lower face (overall or along nerves) and margins of lfts, and axes of inflorescence variably strigulose, pilosulous or pilose with subappressed, incurved or spreading, often yellowish or rufescent hairs up to 0.2-1.3 mm, the foliage bicolored, the usually ample lfts above rich green (when dry commonly rubescent) glabrous or thinly pilosulous, not or scarcely lustrous, paler beneath, the few-fld racemes either axillary to distal lvs and immersed in foliage or forming a corymbiform, shortly exserted panicle.

    Stipules straight erect, or divaricate from pulvinus and sinuately incurved to erect, linear-attenuate (6-)7-16 x 0.2-0.6 mm, the firm blades 1-nerved, deciduous before the lf.

    Lvs (3-)4-10(-11) cm; petiole including moderately swollen pulvinus 12-20(-23) mm, at middle subterete except for narrow ventral sulcus, (0.3-) 0.4-0.8(-l) mm diam; rachis 1.5-4.5(-5) cm; gland erect between proximal pair of lfts, stipitate or less often sessile, in profile (0.7-) 1-2.7(-3) mm tall, the stipe either puberulent or glabrous, the slenderly ellipsoid or ovoid head 0.3-0.45 (-0.6) mm diam, sometimes similar glands at second or third pair; pulvinules 0.8-2.2 mm; lfts (2-)3-7 but of almost all lvs 4-6 pairs, emphatically accrescent distally, the proximal pair half or less as long as the distal and proportionately much broader, the distal pair cuneate-obovate to broadly cuneate-oblanceolate from an obliquely dilated base, obtuse or shallowly emarginate 22-52 x 10-22 mm, 1.7-2.7(-2.9) times as long as wide, the straight centric midrib cariniform beneath, giving rise to ±6-9 pairs of camptodrome secondary nerves, these either finely prominulous (and often differentiated by pale coloring) on both faces or only beneath, a yet finer open mesh of connecting tertiary venules sometimes also prominulous.

    Peduncles 1-35 mm; racemes shortly or subumbellately 1-5 (rarely to 5-15)- fld, the axis becoming (0-) 1 -6 (rarely 20-40) mm; bracts firm oblanceolate to lance-elliptic or -attenuate (3-)4-10 mm, persistent into anthesis, then dry deciduous; pedicels (22-)25-45 mm; young fl-buds obovoid-subglobose pilosulous, but the inner sepals and petals expanding long before true anthesis; sepals firm obovate, oblong-obovate or suborbicular, strongly graduated, the dorsally pilosulous outer ones only ±1/2 as long as the glabrous inner ones, these greenish (6-)7-12 mm, faintly 5-7-nerved from base; petals golden-yellow, all conspicuously clawed, puberulent or pilosulous dorsally at least along nerves, the 3 abaxial ones amply ovate-cordate, the vexillar one emarginate, the 2 abaxial obliquely obovate or oblong-elliptic and slightly longer, the longest (25-)28-39 mm; androecium functionally 7-merous, the puberulent filaments of 4 median stamens 2-4.5 mm, of 3 (or at least 2) abaxial ones 4.5-9 mm, the glabrous or thinly pilosulous anthers of 4 median stamens slightly graduated by pairs, 4.5-6 mm, straight or a little incurved distally, the divaricate-truncate beak 0.3-0.5 mm, those of 3 abaxial ones strongly incurved 8-12 mm, the porrect beak 0.6-1 mm, the beaks of all dehiscent by parallel slits; ovary densely white-strigulose; style filiform 4.5-7 mm, gently incurved but not dilated distally, at apex 0.3-0.45 mm diam.

    Pod pendulous, the stipe 7-15(-18) mm, the linear, straight or slightly decurved, strongly compressed ribbonlike body 8-14(-16) x 0.7-0.95 cm, the sutures undulately constricted at each isthmus, the green, ultimately coriaceous, brownish- nigrescent valves becoming sinuously reticulate-venulose, not elevated over the greatly flattened seeds, the interseminal septa very narrow, early forming lines of fracture, the 1-seeded segments 7-9.5 mm long, dispersed as indehiscent loments; seeds (poorly known) subquadrate 4.7-5 x 4-4.3 mm, the testa casta- neous, slightly roughened sublustrous, the narrowly elliptic areole ±1.5 x 0.4-0.6 mm.—Collections: 71.

    Seasonally dry oak or pine-oak woodlands, thorn forest, savanna thickets and mixed deciduous xerothermic brushlands, in places aggressively abundant following disturbance or grazing, sometimes forming roadside hedges, from sea-level on the Pacific coast of Mexico and Honduras up to 950 m in Morelos, 1100 m in Oaxaca, 1350 m in Chiapas and 1100 m in Nicaragua, interruptedly dispersed from s. Mexico to n. Venezuela: Balsas Depression from e. Michoacan to s. Puebla; Pacific lowlands and interior hill country from w. Guerrero to Oaxaca (especially common around Tehuantepec) and highland interior Chiapas; s.-e. Guatemala in Jalapa and Zacapa (where attaining the Caribbean drainage); lowlands around Gulf of Fonseca in s.-e. Honduras (Valle and Choluteca) and adjacent coastal (Leon) and submontane (Esteli) Nicaragua; lowland n.-w. Costa Rica (Guanacaste); unknown from Panama or Colombia but reappearing in Venezuela: Caribbean lowlands of Falcon; savannas around n. edge of Orinoco valley at ±600-1200 m in Portuguesa (Acarigua), Cojedes (El Pao), and n. Guarico.— Fl. in Mexico and Central America (V-)VI-X; in Venezuela VII-IX.—Chiqui-chiqui (Venezuela); paracata (Michoacan).