Senna benitoensis (Britton & P.Wilson) 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, collected 24.11.1910 (fr), NY!—Peiranisia benitoensis (Britton & Wilson) Britton & Rose, N. Amer. Fl. 23(4): 262. 1930.
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Synonyms
Cassia benitoensis Britton & P.Wilson, Peiranisia benitoensis (Britton & P.Wilson) Britton & Rose
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Description
Species Description - Shrubs 1-3 m, appearing glabrous but the annotinous branchlets, lf-stalks and strongly revolute margin of lfts thinly strigulose with forwardly appressed or incurved hairs 0.15-0.35 mm, the foliage subconcolorous, the lfts lustrous especially above, the inflorescence of racemes axillary to distal lvs, not or scarcely exserted. Stipules erect, thinly herbaceous, narrowly lance-acuminate or linear-attenuate 6-10 x 1-1.5 mm, plane or subrevolute, deciduous. Lvs (disregarding small distal ones) 7-16 cm; petiole including livid pulvinus 16-43 mm, at middle 0.7-1.2 mm diam, 3-ribbed dorso-laterally, openly narrow- sulcate ventrally; rachis ±4-9 cm; gland erect between proximal pair, stipitate, in profile slenderly claviform or phalloid, 1.4-3.4 mm tall, the stipe glabrous, the obtuse black head 0.45-0.6 mm diam; lfts (4-)5-7 pairs, accrescent and proportionately narrower upward, the distal pair oblong-elliptic or obovate obtuse mucronulate 20-34 x 8-11 mm, 2-3.3 times as long as wide, at strongly asymmetric base cordate on proximal and cuneate on distal side, the straight midrib depressed above, cariniform beneath, the 6-10 pairs of fine camptodrome secondary veins either immersed or subprominulous above, sharply raised beneath and there giving rise to a weak open tertiary venulation. Racemes shortly 6-12-fld, the axis with short peduncle together becoming 1.5-4 cm; pedicels 2-3 cm; buds glabrous; fls (including androecium and style) of S. mexicana, the longer sepals ±7 mm and longer petals ±13 mm; ovary minutely puberulent or glabrate; ovules 20-28. Stipe of pod 2-3 mm, the linear ribbonlike straight or gently decurved body 9-15.5 x 0.55-0.75 cm, the papery brownish-nigrescent valves scarcely elevated over seeds, the interseminal septa 0.3-0.6 mm wide, standing 4-5.5 mm apart; seeds subquadrate, moderately compressed 4-4.2 x 3-4.2 mm, pinched at the hilum, the testa in color like that of S. mexicana, but the areole broadly oval 2.6-3.1 x 1.9-2.3 mm.—Collections: 5.
Distribution and Ecology - Habitat scarcely known, reported from woodland and rocky stream-banks, very likely on serpentine, the type from near 900 m, local in the mountains of n.-e. Oriente (Sas. de Nipe and de Moa; Cuchillas de Toar), Cuba.—Fl. XII-IV.
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Discussion
The relationship of S. benitoensis to S. mexicana, and especially to its var. shaferi which shares the phalloid stipitate gland and is sympatric on Sa. de Nipe, is obvious and close, and will need reassessment when fieldwork in the biologically complex highlands of Oriente is again possible. For the present the longer leaves, the glossy leaflets with revolute but not thickened or crimped margins, the narrower pod and, in particular, the broadly quadrate seeds with ample oval pleurogram appear adequately distinctive. The stipitate gland distinguishes S. benitoensis handily from all other forms of S. mexicana, which is in any case represented in Cuba only by var. shaferi and the coastal var. chapmanii. The type-locality, Camp San Benito, was situated, according to Shafer’s field- book (NY), near the head of rio Yamaniguey, apparently on the north slope of the massif Cuchillas de Toar.
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Distribution
Oriente Cuba South America|