Cassia spruceana

  • Title

    Cassia spruceana

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Cassia spruceana Benth.

  • Description

    3.  Cassia spruceana Bentham in Martius, Fl. Bras. 15(2): 92. 1870.—"Habitat in Brasilia boreali, in sylvis "Gapo’ ad Rio Uaupes: Spruce n. 2558."— Holotypus, collected IX. 1852 (fl, fr) near Panure, K (hb. Benth.) (2 sheets)!=NY Neg. 1432; isotypi, GH, NY!

    Cassia sagotiana Bentham in Martius, Fl. Bras. 15(2): 93. 1870.—". . . a cl. Sagotio in Guiana gallica ad flumen Acarouany lecta et sub numero 802 distributa . . . —Holotypus, K (hb. Benth.)! = NY Neg. 1434; isotypi, G, GH, NY, P, W!—Equated with C. spruceana by Ducke, Arch. Jard. Bot. Rio de Jan. 3: 112. 1922.

    Cassia spruceana sensu Bentham, 1871, p. 514, t. 60 (optima, nisi antheris medianis haud re- supinatis); Ducke, 1939, p. 80.

    Cassia sagotiana sensu Bentham, 1871, p. 515.

    Amply leafy trees 10-30 m, with trunk 1.5-2.5(-?) dm diam, the glabrate annotinous branchlets prominently angulate by smooth livid or castaneous ribs descending from each lf-scar, the hornotinous branchlets, lower face of lfts, all axes of inflorescence and sepals finely minutely pilosulous with incurved or sinuous (along costa of midrib beneath sometimes straighter erect) hairs up to 0.1-0.2(-0.3) mm, the vesture of the inflorescence lutescent, the relatively few large subcoriaceous lfts strikingly bicolored, lustrous dark green (when dry brownish) above, pale dull beneath, the racemes (strictly speaking inhibited leafless branchlets) stiffly incurved-ascending, singly or paired, from axils of fallen or soon-to-fall lvs on annotinous branchlets and ± coeval with flush of new foliage.

    Stipules caducous before expansion of associated lf, submembranous, minutely 2-lobed, the subulate ascending lobe ±1 mm, the descending one half as long.

    Lvs (13-)20-36 cm; petiole including livid rugulose pulvinus 17-32(-45) mm, at middle 1.2-2.1 mm diam, widely shallowly sulcate ventrally; rachis (4-)5.5-19 cm, the ventral groove interrupted at each pair of lfts, the longer interfoliolar segments (2-)2.5-5.2 cm; pulvinules (3-)3.5-5.5 mm; lfts 3-5 pairs, accrescent distally, the terminal pair broadly ovate or ovate-elliptic, commonly shortly, sometimes obscurely acuminate (the acumen obtuse or emarginate), ±9-12 x 4-5.5 cm, 1.9-2.4(-2.8) times as long as wide, at obscurely inequilateral base either broadly or narrowly cuneate, the (adult) margin subrevolute, the midrib immersed or shallowly depressed above, cariniform beneath, the 14-22 pairs of camptodrome with random intercalary secondary nerves sharply prominulous on both faces, the open irregular tertiary and reticular venulation prominulous likewise on both faces or more sharply so above than beneath.

    Racemes loosely 15-30-fld, the fls serially expanding below unopened buds, the stiffly incurved-ascending axis (measured from parent branchlet) becoming 7-19 cm; bracts enfolding the young buds, cast off as pedicel begins to elongate, concavely ovate obtuse or subacute 2-3.5 mm, the 2 bracteoles similar but smaller, equally caducous; pedicels ascending, at and after anthesis 10-20(-28) mm; hypanthium scarcely differentiated externally, narrowly turbinate 1-2 mm; sepals reflexed at anthesis, subequilong, ovate-obovate mostly 6-9.5 (rarely 10-12) mm, densely puberulent on both faces, falling with the petals and androecium; petals subhomomorphic, yellow red-veined, widely spreading and almost plane, oblong-elliptic or -oblanceolate mostly 13-15 (rarely 17-19) x 5-8.5 (-9.5) mm, the blade minutely (of abaxial petals sometimes obscurely) auriculate at base, the claw (1-) 1.5-2 mm; androecium glabrous except for dorsally pilosulous fertile anthers, the sigmoid filaments of 3 long stamens 15-19 mm, of 2 interposed slenderly tapering erect 4.5-6 mm, of 3 adaxial antepetalous ones greatly dilated fleshy 3.5-4.5 x 1.2-1.5 mm, of 2 adaxial antesepalous ones less than 2 mm, the anthers of 3 long stamens ovate in dorsal view 1.1-1.7 x 1.1-1.4 mm, those of 4 fertile antepetalous stamens and 1 much diminished antevexillar one all resupinate, the 4 subequal or in 2 pairs (the adaxial smaller) 1.6-3 x 0.9-1.2 mm, those of the 2 antesepalous minute sterile; ovary strigulose-pilosulous, sometimes thinly so laterally, its stipe 3-5.5 mm; style 1.6-2 mm, at apex 0.5-0.65 mm diam, the stigmatic cavity looking inward ±0.1 mm diam; ovules 60-76.

    Pod pendulous, rodlike, terete or a trifle laterally compressed, when fully fertile said to be 3-6 dm, in diam ±2-2.5 cm, the double ventral and single dorsal sutural ribs immersed or almost so, the thin, transversely cracking exocarp early glabrate, brown, livid-castaneous or blackish, the crustaceous endocarp 0.3-0.4 mm thick, the interseminal septa stiffly papery ±0.1 mm thick, the fertile locules 6-9 mm long occupying the whole width of the cavity; seeds (little known) turned broadside to the septa enveloped in a thin pulpy, when dry papery envelope separating from the valve walls, biconvexly ellipsoid ±12 x 7.5 x 6 mm, the smooth atro-purpureous testa moderately lustrous.—Collections: 13.

    Forest margins and high land along rivers, in Ecuador reaching 500 but mostly below 250 m, on terra firme, surviving in capoeira and along fences, sometimes encountered in abandoned fields as though formerly cultivated, middle and lower Amazonian Brazil downstream from lower Rio Branco and on the lower reaches of rios Trombetas and Tapajoz, n.-w. in Amapa to the valley of R. Araguari and to the coastal lowlands of French Guiana; apparently isolated on the upper Vaupes near the Brazil-Colombia border, and on the upper Rio Morona near 77°30'W in e.-centr. Ecuador.—Fl. VIII-XI, ± coincident with lf-fall and flush of new foliage, and with maturity of preceding year’s pods.

    Close to C. leiandra except for the few large leaflets and habitat in non-flooded forest. According to Ducke (1939, p. 80) the pulp enveloping the seeds is inedible, unlike that of C. leiandra. In spite of a notably discontinuous dispersal C. spruceana appears very uniform morphologically, and we readily follow Ducke’s reduction of C. sagotiana, originally supposed to differ in more obtuse leaflets and smaller flowers, characters that have not been borne out by subsequent collections.