Senna insularis (Britton & Rose) H.S.Irwin & Barneby
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Authors
Howard S. Irwin, Rupert C. Barneby
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Authority
Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 1: 1-454.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Holotypus, NY! isotypi, F, US!—Cassia insularis (Britton & Rose) R. A. Howard, J. Arnold Arb. 28: 126. 1947.
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Synonyms
Chamaefistula insularis Britton & Rose, Cassia insularis (Britton & Rose) R.A.Howard
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Description
Species Description - Slender shrubs, when unsupported diffusely bushy or trailing, in brush vinelike, sarmentose or scandent, at anthesis 1-4 m, except for dorsally glabrous sepals pilosulous throughout with fine incumbent or (partly or almost wholly) flexuously erect hairs up to 0.15-0.45 mm, the young stems strongly angulate, the foliage bicolored, the lfts sublustrously dark olivaceous or brownish above, paler dull beneath, the inflorescence narrowly thyrsiform, leafy-bracteate. Stipules erect, weakly setiform or linear-attenuate, straight or curved, 2-6 mm, at base 0.2-0.5 mm wide, deciduous before or after the lf. Lvs (1.5-)2-7 cm; petiole including scarcely differentiated pulvinus (5-)7-20(-23) mm, at middle 0.4-0.8 mm diam, the narrow wings not or scarcely dilated distally, the groove shallow and narrow; rachis 2-8 mm; gland 1 erect from immediately above first pair of pulvinules, short-stipitate, very narrowly lance-ellipsoid acute or spiculiform (0.15-)0.2-0.4 mm diam, glabrous or rarely puberulent at base, the whole in profile 1-2.9 mm tall; pulvinules (0.8-)l-2.2(-2.5) mm; distal pair of lfts sharply deflected from top of rachis, obliquely obovate or elliptic obtuse or emarginate, (10-) 12-43 x (5-)6-21 mm, a little less than 2 to a trifle over 3 times as long as wide, at base shallowly cordate or rounded on proximal and cuneate on distal side, the margin revolute, the slender, little excentric, straight or obscurely incurved midrib with 5-8(-9) pairs of major camptrodome secondary nerves finely prominulous on both faces but a trifle more so beneath, tertiary venulation faint and irregular or immersed, the proximal pair of lfts ±2/3 as long, often proportionately broader. Peduncles with raceme-axis 0.5-3.5(-5) cm; racemes subcorymbosely or quite loosely (2-)4-11-fld; bracts papery yellowish-brownish, broadly ovate to elliptic- oblanceolate acute 1.5-4 x 1.8-2.6 mm, at base half embracing pedicel, deciduous at or before anthesis; pedicels at anthesis 7-12 mm, in fruit much thickened and (7-)9-18 mm; buds globose glabrous, but the sepals minutely ciliolate; sepals subpetaloid yellow or reddish, indistinctly veined, oblong-obovate to -suborbicular very obtuse, little graduated, the longest inner one 5.5-7.5(-8) mm; petals yellow, pubescent dorsally, 3 adaxial subhomomorphic, broadly obovate- or flabellate-cuneate 10-12 mm, 2 abaxial longer, one of them more oblique and enfolding the ovary with 1 stamen, up to 14-21 mm; filaments sparsely pilosulous or glabrous, of 4 median stamens 1.5-2, of 3 abaxial ones (l-)1.8-2.5(-3) mm, the thecae of all either glabrous or thinly pilosulous (3-)3.5-4.5 mm with very short beak 0.2-0.4(-0.5) mm, the two sets of stamens scarcely differentiated; ovary densely gray-pilosulous, the glabrescent style 1.4-2 mm, gently incurved and just below stigma 0.4-0.6 mm diam, the orifice 0.25-0.5 mm diam; ovules 60-78. Pod stiffly ascending on rigid pedicel, the stipe 2-4 mm, the body subcylindroid, straight or gently decurved, (2-)3-8.5 x 1-1.6 cm, the valves at first green becoming lustrous blackish glabrescent and papery, indehiscent, the seeds released by tardy rotting of the fruit; seeds biseriate, compressed-obovoid, 4.6-5.2 mm, the testa mahogany-brown, highly glossy, the areole faintly differentiated, obovate in outline 3-4 x 2.6-3 mm.—Collections: 41.
Distribution and Ecology - Brushy hillsides, thickets in savanna, sea-cliffs, sometimes weedy in hedges, 5-800 m, scattered almost the length of Cuba (all provinces) and Isla de Pinos.— Fl. (VI-)VII-XI(-I), the fr. ripening slowly and long persisting on the branchlets.—Collections: 39.
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Discussion
Senna insularis has the short plump cylindric, relatively few-seeded and irregularly dehiscent pod of Jamaican S. viminea, but differs in the very small obtuse leaflets and in a calyx ampler in relation to the corolla. Vegetatively it more closely resembles east Brazilian S. rizzinii, but this has larger floral bracts, more heteromorphic stamens, a longer style (4-5, not 1.5-2 mm), and a seed-coat with no trace of areole. The close relationship of these three species to S. chrysocarpa is expressed in a common general facies and all four might perhaps be better evaluated as geographic varieties of one.
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Distribution
Cuba South America| Isla de Piños Cuba South America|