Senna cushina (J.F.Macbr.) 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
Holotypus, F! = F Neg. 53945.
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Synonyms
Cassia cushina J.F.Macbr.
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Description
Species Description - Trees 6-10 m, with habit and pubescence almost of S. viarum, but the lfts much more numerous and pedicels shorter. Stipules obliquely lanceolate 10-16 x 3-4 mm, reflexed and coiled horizontally around stem, deciduous. Lvs ±3-4 dm; petiole 5-8 x 0.2-0.3 cm; rachis 16-24 cm; lfts 7-16 pairs, all broadly lance-acuminate, the longest (usually penultimate) pair mostly 8-11 x 1.5-3 cm, all dull olivaceous, glabrous above except sometimes for a line of hairs along the depressed midrib, beneath pallid and pilosulous with loose shining hairs up to 0.7-1 mm, the margin revolute, the ±14-16 pairs of camptodrome secondary veins immersed or faintly raised above, sharply prominulous beneath.Inflorescence of S. viarum, but pedicels at full anthesis only 11-20 mm, like those of S. pistaciifolia; bracts deltate-flabellate ±2.5-3 x 2.5-3 mm, beyond middle several-nerved, thinly pilosulous dorsally; fl-buds almost or quite glabrous, the brownish-yellow sepals up to ±11 mm; long petals ±16 mm; androecium of S. viarum, the filament of 2 long anthers ±4 mm; ovary either densely velutinous or thinly puberulent; style ±4.5 mm; ovules 16-24. Pod unknown.—Collections: 2.
Distribution and Ecology - Humid woodland of the monte formation, ±2000-2300 m, known only from 2 localities on the Amazonian slope of the Andes in n.-e. and centr. Peru: Maranon valley in Amazonas (above Pomacochas, prov. Bongara); and on a fork of rio Pachitea in e. Huanuco (Cushi).—Fl. VI-IX.
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Discussion
Our inchoate concept and description of S. cushina are derived from two flowering specimens, the typus which has mature flowers but has lost bracts and stipules, and Ferreyra & Ancleto 15183 from Amazonas, which retains both bracts and stipules at the earliest stage of anthesis. Although to some degree complementary they fall far short of providing conclusive evidence of a species distinct from the already highly variable S. pistaciifolia, widespread at similar elevations in the Peruvian Andes. The relatively numerous lance-acuminate leaflets, marginally revolute and loosely pilosulous beneath, provisionally separate the species both from S. pistaciifolia and the closely allied S. viarum; but the taxonomy of the whole group will need reevaluation as more is learned about the details of dispersal, about variation in shape and number of leaflets, and particularly about the configuration of the mature pod.
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Distribution
Amazonas Peru South America| Huánuco Peru South America|