Cassia cotinifolia

  • Title

    Cassia cotinifolia

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Cassia cotinifolia G.Don

  • Description

    115.  Cassia cotinifolia G. Don, Gen. Hist. Diehl. Pl. 2: 445.1832. — Typus infra sub var. continifolia indicatur.

    Coarsely leafy undershrubs from a xylopodium, with one to several erect or ascending, stiffly flexuous, smooth, mostly simple, green or livid stems 4-8(-10) dm, glabrous either up to the viscid-setulose inflorescence or up to the setulose ovary and pod, the foliage stiffly chartaceous or coriaceous, veiny, the lfts not dorsiventrally differentiated, the racemes axillary from distal nodes and terminal, at least the upper ones far surpassing the foliage, the fl-buds serially racemose above the expanded flowers.

    Stipules erect, narrowly triangular-subulate, 0.4-1 mm, caducous (perhaps sometimes obsolete).

    Lvs4.5-14 cm, petiolate; pulvinus ovoid, dilated, 1.5-4 mm, when dry coarsely wrinkled; petiole stiffly ascending at ±45°, straight or slightly curved outward, 1.2-7 cm, 0.6-1.6 mm diam, shallowly sulcate proximally thence subterete, at apex abruptly dilated under the terminal lfts; rachis reduced to a rudimentary subulate or triangular appendage shorter than the pulvinules; lfts 1 pair, deflected at ±45° from tip of rachis and turned edgewise, proximal margin toward meridian, on inflated, when dry coarsely wrinkled pulvinule 1.2-4(-6) mm, in outline subsymmetrically orbicular to orbicular-obovate or -reniform, obtuse and minutely cuspidulate by the excurrent midrib or commonly shallowly emarginate, 2.5-8.5 x 2.5-8 cm, commonly cuneately or deltately contracted at extreme base into the pulvinule, the cartilaginous margin entire, plane, narrowly aliform, thinner than the subcontiguous or distant intramarginal nerve formed by camptodromous anastomosis of the secondary venation, the blades stiffly chartaceous to rigidly coriaceous, brownish-olivaceous, concolorous, on both faces prominently pallid-nerved, in most forms prominently reticulate as well as penninerved, the subcentric midrib straight or almost so, the secondary veins ±6-10 pairs, either divaricately ascending on both sides of midrib in normal pinnate fashion or the first 2-3 on the proximal side arising from the pulvinule and ascending well beyond middle of blade.

    Racemes many-fld, arising from 2-several distal lf-axils and often terminally paniculate (rarely solitary), most of them rising well above the foliage, the axis becoming (5-)7-30 cm, several fls simultaneously expanded; bracts subulate, 1-3.3 mm, decurrent as a rib on the axis, tardily deciduous; pedicels ascending, very slender, 8-17(-20) mm, bracteolate 1-4.5 mm below calyx; bracteoles resembling bracts, 0.6-1.5 mm, deciduous; buds plumply ovoid to subglobose, obtuse, thinly viscid-puberulent or glabrous; sepals either yellowish-green or red, obovate to elliptic-oblanceolate obtuse, 5.5-7 x 2.4-4.2 mm; petals yellow, 4 rather narrowly ascending at full anthesis, slightly unequal, obovate-cuneate, to 9.5-12 x 4.5-7 mm, the fifth shorter firmer, falcately oblanceolate, coiled; ovary densely yellow-setulose, viscid; ovules (5-)6-8.

    Pod oblong or linear-oblong in outline, almost straight, abruptly short-beaked, (2.5-)3-4.5 x 6-10.5 mm, the chartaceous reddish-brown, finally nigrescent valves glutinously villosulous and setulose; seeds (of var. glaberrima, otherwise unknown) 5-5.5 x 3.5-3.9 mm, soot-black, dull, faintly lineolate.

    A species readily recognized by the syndrome of ample suborbicular unijugate coriaceous, glabrous and eglandular leaflets with eglandular petiole and small racemose flowers, but somewhat diverse internally. Four geographic races may be distinguished:

    1.  Plant glabrous up to the inflorescence, this like the sepals viscid-villosulous and -setulose; petiole 1.2-3.5 cm; pod (7.5-)8-10.5 mm wide; intramarginal nerve of lfts formed by anastomosis of the secondary veins running distant 1 mm or less from margin; range southeastern, known only from Minas Gerais and perhaps the extreme s. -e. corner of Goias (Rio S. Marcos).

    2.  Reticulation of lfts coarse and open, the larger areoles defined by elevated venules much >1 mm diam; lfts mostly as long or a little longer than wide, seldom at all cordate, the blade ± cuneately contracted at junction with the pulvinule; w. -centr Minas Gerais, from the Triangulo (and perhaps adjacent Goias) e. to Serra do Cipo, there contiguous with the next.

    115a. var. cotinifolia

    2.  Reticulation of lfts extremely fine and close, the larger areoles <1 mm diam; lfts mostly wider than long and reniform-cordate, not backwardly contracted into the pulvinule; s. Serra do Espinhaco, between Diamantina and Belo Horizonte.

    115b. var. leptodictya

    1.  Plant fully glabrous up to the ovary and pod, the axes of inflorescence ± glutinous but lacking villi or setules, the sepals glabrous; pod 0.6-0.75(-0.8) mm wide; range western from D.F through centr. Goias into Mato Grosso.

    3.  Petiole 1.5-3.5 cm; lfts thickly coriaceous and coarsely venulose-reticulate, the venation elevated up to the fourth order of ramification; intramarginal nerve of var. cotinifolia) known only from Distrito Federal.

    115c. var. percoriacea

    3.  Petiole 3.5-7 cm; lfts stiffly chartaceous, openly and delicately venulose, the venation beyond third order of ramification obscure and not or scarcely elevated; intramarginal nerve formed by anastomosis of the secondary veins running 1—3 mm distant from margin; s-w. Goias (Serra do Caiapo) and Mato Grosso.

    115d. var. glaberrima