Senna hirsuta var. leptocarpa

  • Title

    Senna hirsuta var. leptocarpa

  • Author(s)

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna hirsuta var. leptocarpa (Benth.) H.S.Irwin & Barneby

  • Description

    138d. Senna hirsuta (Linnaeus) var. leptocarpa (Bentham) Irwin & Barneby, stat. nov. Cassia leptocarpa Bentham. Linnaea 22: 528. 1849.—"Ad Zapative [=Sepitiba, Edo. Guanabara] legit Pohl et prope Rio de Janeiro, Luschnath."—Lectoholotypus, Pohl s.n., K (hb. Benth.)! = NY Neg. 1454; isotypus, Pohl 5654, W!

    Appearing glabrous but the lfts finely strigulose beneath with appressed hairs to 0.2-0.4 mm, either glabrous or micropuberulent above, loosely finely reticulate on both faces, often with a yellowish-green cast when dry; petiole 3-9 cm; rachis 7.5-14.5 mm; gland ovoid or conic-ovoid, as long as or a little longer than wide; peduncles 1-2.5 cm; racemes 7-20-fld, the axis including peduncle becoming 3-7.5 cm: inner sepals 5.5-7 mm; longer petals 12-14 mm; ovules ±70-80; pod 16-27 x ±0.4-0.45 cm, sparsely minutely strigulose, evenly arched outward.— Collections: 10.

    Disturbed woodlands, 100-660 m. apparently uncommon, known only from Rio de Janeiro. Guanabara and s. Minas Gerais, Brazil.—Fl. I—III

    As here defined, var. leptocarpa is readily separated from all other forms of S. hirsuta by the openly reticulate, not simply penniveined or simply costate leaflets, and from other varieties native in the same latitudes by the glabrate stems and foliage. We return, at varietal level and in a new context, to Bentham’s original concept of Cassia leptocarpa, then as now known only from a small sector of southeastern Brazil within a 200 km radius of Rio de Janeiro; and reject his later circumscriptions (1870, 1871), stretched to accommodate, as C. leptocarpa var. hirsuta, the Mexican, Central American and western South American sennas in which the same narrow, elongated pod coincides with pilosulous or hirsute foliage (our vars. puberula and hirta). Also repudiated is the corrupt concept of Britton & Rose (1930, p. 256, sub Ditremexa) who, by a process of drift, had come to identify C. leptocarpa primarily with the hirsute North American var. hirta.