Senna itatiaiae 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; isotypus, K.
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Description
Species Description - Arborescent shrubs to ±2 m, the virgate smooth striate hornotinous branches becoming after first season castaneous lustrous, glabrous throughout except for densely minutely puberulent sepals, the dull olivaceous foliage subconcolorous, the inflorescence of axillary racemes surpassed by foliage. Stipules thinly herbaceous pale green, obliquely ovate, abruptly acuminate 12-17 x 6.5-8 mm, at base subcordately amplexicaul on side opposed to petiole, tardily deciduous. Lvs 9.5-15 cm; petiole including wrinkled pulvinus (2-)3-4.5 cm, at middle ±0.7-1.1 mm diam, rounded dorsally, deeply sulcate ventrally; rachis 3.5-7 cm; glands between at least 2 proximal or between all but the distal pair of lfts sub-sessile ovoid acute or obtuse ±1.5-2 x 0.5-0.9 mm; pulvinules 2-2.5 mm; lfts 5-6 pairs, a little accrescent distally but the penultimate sometimes longest, all broadly elliptic from asymmetrically rounded base, obtuse but minutely mucronulate at apex, the distal pair (2.6-)3-4.2 x 1.2-2 cm, 2-2.5 times as long as wide, the submembranous margins plane or incipiently revolute, the centric midrib immersed above, carinate beneath, the 7-9 pairs of camptodrome secondary veins weakly prominulous on both faces, tertiary venulation scarcely perceptible. Peduncles ±5-7 cm; racemes openly ±25-30-fld, the axis at mid-anthesis ±4-6 cm; bracts resembling stipules in texture, lance- or the lowest ovate-acuminate 5-12 x 2-4 mm, persistent at least into full anthesis; pedicels ±1.3-2.4 cm; fl-buds subglobose densely puberulent; sepals yellowish brown-tinged, obovate obtuse subequal 5.5-7 mm; petals glabrous yellow, when dry stramineous brown- veined, all similar in size and shape except the dorsal one a trifle broader, obovate-flabellate short-clawed, ±9-10 mm long; androecium glabrous, the filaments of 4 median anthers 1.5-2.4 mm, of 3 abaxial ones 2.5-3 mm, the anthers brown, those of 4 median stamens nearly straight 3.7-4.3 mm, of 3 abaxial ones lunately incurved 4.5-5 mm, all abruptly truncate at apex; ovary glabrous, style ±1.5 x 0.25 mm; ovules 24-32. Pod obliquely geotropic stipitate, the stipe ±5 mm, the oblong-cylindric body ±5.5 x 1.8 cm, abruptly contracted at both ends, the thin indehiscent valves separating when ripe into a brown almost smooth exocarp and a pallid papery endocarp, the cavity lacking pulp, the membranous interseminal septa complete, ±3 mm apart; seeds 2-seriate, turned broadside to the septa, plumply compressed- obovoid ±6.5 x 3.5 mm, the lustrous brown testa microscopically pitted, exareolate.—Collections: 3.
Distribution and Ecology - Disturbed moist forest, in residual thickets and on roadsides, ±2250 m, known only from the upper slopes of Mt. Itatiaia near 22°25'S in n.-w. Rio de Janeiro, Brazil.—Fl. XI-IL
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Discussion
A species very distinct in its pallid semicordate stipules and short sausageshaped pod. Except that the sepals are densely puberulent dorsally, the individual flower is almost that of S. organensis, and the relatively few ovules are also suggestive of ser. Stipulaceae, to which we provisionally referred the flowering typus. A pod from the type-locality (V. F. Ferreira 171, RB) proves, however, to be of the cylindric type characteristic of ser. Coluteoideae in which the seeds are doubled up into two fully separated parallel ranks. Here may be appropriately mentioned sterile specimens (Glaziou 8417, C, K, P) of a senna with foliaceous stipules resembling those of S. itatiaiae but about as wide as long and up to 2 cm diam. They were collected, according to Glaziou’s Liste, on the "rochers du Retiro" at Petropolis, Rio de Janeiro. The leaves suggest some coarse form of S. subulata, but are potentially larger (to 24 cm long) and may have up to eight pairs of leaflets more prominently veined than those of any species with similar stipules. Their identity will remain an intriguing puzzle until flowering specimens can be obtained.
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Distribution
Rio de Janeiro Brazil South America|