Senna acutisepala (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 1: 1-454.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Holotypus, dated III. 1817, collected therefore somewhere in present s.-e. Bahia, M (3 sheets)! = NY Neg. 9305; isotypus, GOETT!
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Synonyms
Cassia acutisepala Benth.
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Description
Species Description - Shrubs 2.5-3 m of unknown habit, with terete smooth finely striate pale brown annotinous stems, appearing glabrous but the young branchlets, lf-stalks and axes of inflorescence sparsely strigulose with subappressed hairs up to 0.2-0.35 mm, the sepals and upper face of the thinly chartaceous lfts truly glabrous, the lfts olivaceous, faintly bicolored, scarcely lustrous above, dull beneath, the inflorescence an elongate thyrsiform panicle, the racemes all axillary to and shorter than developed lvs. Stipules erect setiform 3-9 mm, at base 0.5-0.8 mm wide, early dry, disjointing before the lf. Lvs 9-17 cm; petiole including slenderly ellipsoid wrinkled pulvinus 1.3-3 cm, at middle 0.8-1.7 mm diam, keeled dorsally, openly shallowly sulcate ventrally, subtriquetrous in section; rachis 1.5-3.2 cm, a little longer or shorter than petiole; gland 1 between the proximal pair of lfts, stipitate, in profile claviform 2-3 mm tall, the glabrous stipe shorter than or ± as long as blackish head; pulvinules a little dilated, 2.5-3.5 mm; distal pair of lfts subsymmetrically elliptic 6-11 x 2.2-4.3 cm, acuminate at both ends, at apex obtuse mucronulate, at base on both sides cuneately contracted into the pulvinule, the margin revolute, the centric straight midrib giving rise on each side to ±9-14 major camptodrome with some intercalary secondary veins, these with the tertiary connecting and reticular venules all prominulous on both faces, the ultimate defined areoles <1 mm diam. Peduncles with raceme-axis (1.5-)3-7 cm, much shorter than subtending lf; racemes loosely shortly 4-14-fld; bracts narrowly lance-attenuate 4-7 mm, deciduous by full anthesis; pedicels at anthesis 16-26 mm; sepals pallid becoming papery, broadly lanceolate acute, subequal in length 10-14.5 x 3-4.3 mm, strongly nerved dorsally; young fl-buds acute; androecium exposed much before development of petals; petals yellow, puberulent dorsally, beyond the claw ovate- oblong 14-22 x 5-9 mm, one broader abaxial one obliquely incurved around 2 longer stamens; filaments glabrous or almost so, those of 7 fertile stamens 2-4 mm, of subequal length or the 3 abaxial a little longer, the thecae either glabrous or remotely strigulose distally, those of 4 median stamens 4-7 mm, with abruptly divaricate 2-furcate beak 0.5-0.9 mm, those of 3 abaxial ones 5-7 mm with longer but almost as strongly sigmoid-divaricate beak 1.4-1.6 mm; ovary gray-strigulose; style 4-5 mm glabrescent, incurved distally, strongly dilated behind and below stigma and there 1.2-1.5 mm diam, the stigmatic cavity ±0.75-0.9 mm diam; ovules 90-112. Pod and seed unknown.—Collections: 4.
Distribution and Ecology - Mata costeira below 100 m and inland in disturbed mata de cipo at 900 m, apparently local, known only from 4 collections: the typus, surmised by Bentham to have been collected in Espirito Santo, but more likely in southern Bahia inland from or near Ilheus; from Bahia without more exact data (Blanchet 3638); from e. of Maracas, Bahia, lat. 13°30'S (Mori & dos Santos 11783); and from near Valença, Bahia, lat. 11°30'S (de Jesus & Santos 345/398).—Fl. III-VI.
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Discussion
This rare and still not fully described senna appears strongly characterized by the syndrome of leaflets symmetrically cuneate at base, a leafy-bracteate inflorescence, and subequal lanceolate acute sepals glabrous or almost so dorsally.
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Distribution
Bahia Brazil South America| Espirito Santo Brazil South America|