Senna collicola 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, BM, MO!
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Description
Species Description - Slender shrubs up to ±1 m, the prominently lenticellate leafless annotinous stems branched distally, the densely leafy young stems, lf-stalks and inflorescence pilosulous with incurved-spreading whitish hairs up to 0.6 mm, the ciliolate lfts facially glabrous except for a minutely puberulent line along costa above, the foliage bicolored, when dry brownish-olivaceous above, paler beneath, the few- fld, shortly pedunculate racemes crowded in upper lf-axils and forming a small immersed panicle. Stipules erect, thinly herbaceous, narrowly lanceolate ±4-6 x 1-1.5 mm, at base obscurely cordate on side further from petiole, early deciduous. Lvs 7-14 cm; petiole including little swollen pulvinus 3-25 mm, at middle 0.5-0.8 mm diam, carinate dorsally, very narrowly and shallowly sulcate ventrally; rachis 4-7.5 cm; gland near base of lf-stalk, contiguous or almost so to pulvinus, sometimes accompanied by a pair of small lfts, sometimes up to ±2 cm distant from proximal pair, in either case stipitate incurved-erect, in profile 2-3 mm tall, the slenderly lanceolate-acute body 0.3-0.5 mm diam, often similar but more slender glands between 1-3 distal pairs of lfts; pulvinules ±1 mm; lfts 6-8 pairs, the proximal smallest, the rest slightly or scarcely accrescent, the longer ones narrowly subobliquely lance-attenuate 2-3.5 x 0.2-0.4 cm, ±7-14 times as long as wide, the margins strongly re volute, the midrib sulcate ventrally, cariniform dorsally, the ±6-7 pairs of obscurely camptodrome secondary veins faintly raised dorsally on proximal half of blade, invisible distally and on ventral face. Peduncles 3-17 mm; racemes very shortly subcorymbosely 3-5-fld, the axis up to 6 mm; bracts thinly herbaceous lanceolate 5.5-7 x 1.7-2.3 mm, persistent into anthesis; pedicels at anthesis ±13-15 mm; fl-buds ascending, densely shortly pilosulous; sepals firm, fuscous except for pallid margin, well graduated, the suborbicular outer ones 4-5 mm, the elliptic-obovate inner ones 6.5-9 mm; petals glabrous orange-yellow drying whitish brown-veined, in shape like those of S. ligustrina, the longest 10-12 mm; androecium glabrous, the staminodes ±1.4 mm wide, the filaments of 4 median stamens 1.5 mm, of 2 long abaxial ones dilated 3.5-4.5 mm, the anthers of 4 median stamens 4.5 mm, obliquely truncate 2-porose, those of 2 long abaxial ones lunately incurved 5.5 x 1.3 mm, scarcely constricted subapically, brownish yellow-tipped, the pollen-cup only 0.4 mm long, the centric abaxial stamen rudimentary; ovary pilosulous laterally; style ±2.5 mm, at apex moderately thickened 0.4 mm diam, incurved only through ±45°, the lateral stigmatic cavity longer than wide. Pod incompletely known from year-old fragments, apparently much like that of S. ligustrina and S. stenophylla, the papery valves ±6 mm wide; seed unknown.—Collection: 1.
Distribution and Ecology - Habitat not recorded, known only from the type-locality near 1800 m in the mountains of Departement de l’Ouest, Haiti.—Fl. VI-VII(-?).
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Discussion
The evidently rare and local S. collicola appears, like the related Cuban S. stenophylla, to be derived from relatively widespread S. ligustrina. All three have the same slender pointed petiolar gland which varies in position, sometimes from leaf to leaf on one plant, from genuinely basal (contiguous to the pulvinus) to interfoliolar. The flowers and pods, so far as known, are essentially uniform, but the foliage and consequently the general facies of the plants is markedly different, the larger leaflets of S. ligustrina being 2.5-7 times (in Hispaniola less than 7 times), those of S. collicola 7-14 times, and those of S. stenophylla 25-70 times longer than wide. Senna collicola stands alone in its pilosulous sepals and in the less pronounced curvature of the style which determines the lateral rather than retrorse orientation of the stigmatic cavity.
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Distribution
Ouest Haiti South America|