Senna viciifolia (Benth.) 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 2: 455-918.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Lectoholotypus, collected "between Turmero and La Victoria," Aragua, Venezuela, 14.111.57 (fl, fr), Fendler 2230, K (hb. Benth.)! = NY Neg. 1561; paratypi, collected "between La Victoria and Biscaina," 1.11.57 (fl), Fendler 2231, K (hb. Benth., hb. Hook.)
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Synonyms
Cassia viciifolia Benth., Peiranisia viciaefolia Pittier, Peiranisia magniflora Britton & Rose ex Pittier
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Description
Species Description - Arborescent shrubs and slender trees at anthesis 1.5-8(-10) m, closely resembling and related to C. robiniifolia but the drought-deciduous foliage proteranthous and the inflorescence of 2-3-fld racemes borne on brachyblasts developing after or only shortly before fall of the suffulcrant lf, the hornotinous branchlets and foliage pilosulous with loosely ascending-incurved hairs up to 0.3-0.75 mm, the bicolored lfts above dark green (brunnescent in drying) and puberulent or exceptionally glabrate, below paler and densely pilosulous, when young often canescent. Stipules erect linear-attenuate 3-14 x 0.2-0.45 mm caducous. Larger lvs (8-)10-18(-21) cm; petiole including dilated, when dry wrinkled pulvinus (1.7-)2.2-3.7 cm, at middle 0.6-1 mm diam, openly grooved ventrally; rachis (3.5)4-10 cm; glands between 2-3(-5) proximal pairs of lfts, short-stipitate or sessile (l-)2-3.2 mm, the compressed or subclaviform body 0.3-0.7 mm diam; lfts (5-)6-9(- 10) pairs, strongly accrescent upward, the distal pair usually oblanceolate or narrowly obovate obtuse, rarely elliptic-oblanceolate and deltately subacute 3.6-6 x (0.9-) 1-2.3 cm, (2.2-)2.5-4.2 times longer than wide, the base, margin and venation as in C. robiniifolia. Axis of flowering brachyblasts up to 2 cm, often condensed into a short spur or knot; racemes all or almost all (l-)2-fld, the axis 0-1 mm or rarely elongating to bear a third fl 4-5 mm above the pair; peduncles 9-23 mm; pedicels 16-35 mm, straight in fruit, at base subtended laterally by a compressed-fusiform, early divaricate and deciduous gland; buds subglobose, glabrous or almost so; sepals all obovate-suborbicular, strongly graduated, the largest innermost one (6.5-)7-10.5 mm; petals (of Interglandulosae) glabrous, the longest (20-)22-33 mm; androecium glabrous, the filaments of 4 median stamens and 3 staminodia fused at base, 0.8-2 mm, those of 3 abaxial ones free 2-3.8 mm; anthers of 4 median stamens 4.5-5.6 mm, commonly constricted just below the very short divaricate beak, this dehiscent by one U-shaped slit, those of 3 abaxial ones 4.5-7 mm, contracted into a tubular, distally a little dilated and 1-porose beak 2.5-4.2 mm; ovary strigulose or glabrous; style and ovules of C. robiniifolia. Pod of C. robiniifolia, 6-7 mm wide; seeds (little known) paddle-shaped 3.2 x 2.4 mm, the testa castaneous sublustrous, the areole oval 1.2 x 0.8 mm.- Collections: 37.
Distribution and Ecology - Deciduous woodland, xeromorphic brush-woodland, thickets in savanna and along highways, 300-700 m, locally plentiful in intermontane valleys and around n. edge of the Orinoco valley in n.-w. Venezuela, from e. Lara to n. Aragua and n.-w. Anzoategui, n. Cojedes and n. Guarico.-Fl. XI-II, sporadically later.
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Discussion
A species closely related to the marginally sympatric C. robiniifolia, which it resembles in form of foliage (except leaflets more commonly obtuse), in the flower, and in the connate filaments of the staminodia and median fertile stamens, but technically different in the somewhat larger sepals, the glabrous petals, and more importantly in the rhythm of anthesis and form of the inflorescence. In C. robiniifolia the racemose elements of the paniculate inflorescence are borne on annotinous branchlets axillary to recently developed leaves or, as the season advances, paniculately at the leafless apex of the current year’s growth, anthesis coinciding with the period of greatest vegetative activity. By contrast in C. viciifolia the abbreviated axis of the panicle takes the form of a brachyblast arising from the axil of an old leaf soon due to fall or of one already fallen; and anthesis coincides with a season of drought and vegetative quiescence. Where they are sympatric or closely vicariant, C. robiniifolia flowers from July to December when in full leaf, C. viciifolia from December to January, sporadically later, abundantly and characteristically only from leafless branchlets. It might be thought that these two sennas, so similar in most respects, are merely seasonal aspects of one climatically adaptable species; but the perfect correlation in C. viciifolia of few petiolar glands, larger sepals, glabrous petals, protantherous foliage and condensed panicle suggests that they are biologically distinct entities adapted to different climatic regimes. lf our still rather incomplete data on flowering seasons are accurate, the two species, by virtue of dyschronous anthesis, are unlikely or unable to exchange pollen. The typi of C. viciifolia and P. magniflora, which originated from the east and west ends, respectively, of Lago de Valencia, are unquestionably conspecific in the most exact sense. At the time Pittier described P. magniflora he appears to have interpreted as C. viciiflora the Venezuelan form of C. biflora with pubescent foliage.
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Distribution
Lara Venezuela South America| Aragua Venezuela South America| Anzoátegui Venezuela South America| Cojedes Venezuela South America| Guárico Venezuela South America|