Chamaecrista desvauxii var. saxatilis

  • Title

    Chamaecrista desvauxii var. saxatilis

  • Author(s)

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Chamaecrista desvauxii var. saxatilis (Amshoff) H.S.Irwin & Barneby

  • Description

    1i. Chamaecrista desvauxii (Colladon) Killip var. saxatilis (Amshoff) Irwin & Barneby, comb. nov. Cassia tetraphylla Desvaux var. saxatilis Amshoff, On S. Amer. Papilionaceae 27. 1939.—"Suriname, Upper Litanie Riv. (mount Knopaiamoi, Rombouts 809 . . .)."—Holotypus, U!—C. saxatilis (Amshoff) Irwin, Mem. N.Y. Bot. Gard. 12:(1): 86, fig. 348 (map). 1964.

    Slender erect, usually single-stemmed from shallow roots, paniculately branched distally 3-10 dm, the branches either strictly ascending or plagiotropic, the foliage olivaceous glabrous or glabrous ciliolate; stipules submembranous broadly lance-ovate acute or acuminate, persistent, the larger ones 6-14 x 2-4 mm, as long or only 1/3 as long as internodes; longer lf-stalks 4-8 mm, the petiole (3-)3.5-6 mm, the rachis 1-2.5; petiolar gland scutellate or shallowly concave 0.5-1.4 mm diam subsessile or shortly stipitate, in profile obconic or squatly studshaped, 0.2-0.8 mm tall; lfts subdimidiately obovate or obliquely broadly oblanceolate, the proximal pair usually slightly larger (in sleep covering the distal pair), the larger ones 10—19(—23) x 4-8(-9) mm; pedicels very slender wiry 2-3.3(-4) cm, surpassing If; longer sepals (7—)9—11 mm; long petal (5—)7—11(—14) mm; pod 17—27(—38) x 4.5-5.5(-7) mm; ovules (6—)7—9(—11).

    Sand savanna and outcrops in forest or along rivers, a pioneer colonist of temporary river islands, soil-filled crevices and depressions in granite rock faces, 10-550 m, interior Surinam, French Guiana, and Amapá, Brazil, from the middle Coppename River (Voltz Berg) e. to Rio Araguarí, s. to s. slope of Sa. Tumucumaque on the headwaters of Rio Jarí, in French Guiana and Amapá coming out to the coast (at Cayenne) or the coastal plain (downstream from Porto Platon).—Fl. year around.

    Readily distinguished from sympatric var. mollissima by the slender habit, small flower, and short few-ovulate pod. The variety is more closely related to the distantly allopatric var. triumviralis which occupies similar microhabitats on granitic knobs and associated savannas of the middle Orinoco valley, but differs in diminished leaf- and stipule-blades, smaller sessile glands, and shorter pedicels.