Cassia acosmifolia var. acosmifolia

  • Title

    Cassia acosmifolia var. acosmifolia

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Cassia acosmifolia Mart. var. acosmifolia

  • Description

    148a. Cassia acosmifolia Martius ex Bentham var. acosmifolia. C. acosmifolia Martius ex Bentham, I.c., sens. str. — "Habitat. . prope S. Joao del Rey, prov. Minas Geraes, et in silvis ad Monte Santo prope Bahiam: Martius." — Holotypus, consisting of 3 sheets, probably (see discussion) representing one collection but with locality-data as cited, M! = NY Negs. 8826 and 8827. Characters as given in the key. — Collections: 6.

    Gallery margins and cerrado thickets, 250-650 m, rare or seldom collected, known from scattered stations on the upper Rio Parnatba in s. Maranhao (Loreto) on Rio Itaueira (Golfes) in s. Piaui, on Rio Ondas fork of Rio Sao Francisco in w. Bahia, and from the controversial type-locality, perhaps at Monte Santo in n.-e. Bahia (near 10° 25' S, 39° 20' W), to be expected elsewhere in Maranhao and Bahia. — Fl. III-V.

    Beyond the woodier habit, the shorter herbaceous branchlets, the more contracted racemes and the narrow sepals emphasized in the key, var. acosmifolia differs from var. oropedii in its firmer, stiffer stipules and the generally more slender petioles (mostly 0.3-0.5, not 0.5-0.8 mm diam). So far as known it occurs in the lowlands only, whereas var. oropedii is recorded only from 850 m upward.

    The material from which Bentham described C. acosmifolia Mart, is now mounted on three sheets, two collected supposedly in 1818 at Sab Joao del Rei in southern Minas Gerais and one in 1819 "ad montem Sanctum prov. Bahiae", presumably the present cidade Monte Santo in the northern interior part of the state. The five mounted pieces appear in all details identical, not only morphologically, but in minutiae of preparation, discoloration, and stage of maturity. It seems impossible that Martius could have obtained, in successive years at points 1300 km apart, two lots of specimens so precisely similar, and we believe that the double locality, as copied faithfully from the labels by Bentham, must be due to some error of long standing. Many collectors have been active in southern Minas in the centruy and half since Martius visited Sao Joao del Rei but none have encountered C. acosmifolia again in that region. On the other hand the center of speciation for ser. Absoideae is in northeastern Brazil and plants similar to, even though not in every point precisely like that of Martius, have been collected only in Bahia and Maranhao. We suppose, therefore, pending verification by a modern collection exactly matching Martius' plant, that the type-locality of C. acosmifolia is the Monte Santo near 10° 25' S, 39° 20' W in Bahia, visited by Martius (acc. Urban, 1906, p. 60) in March 1819.