Cassia leiandra

Title

Cassia leiandra

Authors

Howard S. Irwin, Rupert C. Barneby

Scientific Name

Cassia leiandra Benth.

Description

2.  Cassia leiandra Bentham in Martius, Fl. Bras. 15(2): 94, t. 30 (optima, nisi staminum breviorum antherae erectae delineantur). 1870.—"Habitat in provincia do Alto Amazonas secus flumen Rio Negro: Schomburgk n. 894.; ad ostium ejusdem fluminis: Spruce n. 1557.; secus flumen Amazonum ad Punta Paricatuba: Spruce n. 439.; in sylvis Manaqueri prov. Para [? Amazonas]: Martius; prope Borba ejusdem prov. [on lower Madeira in Amazonas]: Riedel; in ripa fluvii S. Francisci prope Malhada, prov. Bahiensis: Martius."—Lectoholotypus, Schomburgk 894, mislabelled ‘British Guiana,’ collected probably (fide Sandwith) near Manaus, K (hb. Benth.)! = NY Neg. 1435; isotypus K (hb. Hook.)! paratypi, Spruce 439, 1557, K!—Martius s.n. from Bahia, not found at BR or M, is presumed either misidentified or mislabelled.

Trees with simple or branched trunk and rounded crown, commonly encountered at 5-10 m, attaining 20 m, and rarely seen as a (presumably immature) shrub 3 m tall, the older stems fuscous, eventually lenticellate, obtusangulate by dark smooth ribs descending from each lf-scar, the young stems and foliage densely pilosulous or puberulent with spreading-incurved, often lutescent hairs up to (0. l-)0.2-0.5 mm, the foliage red at flush, when adult 2-colored, when dry brownish-olivaceous dull beneath, above darker lustrous and except along the midrib glabrous or almost so, the erect racemes arising singly or paired from axils of annotinous branchlets, usually below the current lvs but sometimes accompanied by persistent old ones of the previous season.

Stipules caducous before expansion of the associated lf, consequently little known, subulate or triangular-subulate 1-2.5 mm.

Adult lvs 14-30 cm, the shallowly openly sulcate petiole proper ± as long as the interfoliolar segments of rachis, these up to 13-25 mm; pulvinules (1-) 1.5-2.5 mm; lfts (5-)6- 11 pairs, either gently accrescent distally or except for 1-2 proximal (and exceptionally the distal) decrescent pairs all of subequal length, the larger distal pairs in outline ovate- or oblong-, rarely lance-elliptic, obtuse (4.5-)5-7(-7.5) x 1.4-2.5 cm, ±2.2-3.4 times as long as wide, at obtuse or broadly cuneate base ± inequilateral, broader on distal side, the margin subrevolute, the midrib depressed above, cariniform beneath, the 14-21 pairs of major camptodrome and subequally strong intercalary secondary veins prominulous on both faces, an irregular tertiary venulation always sharply raised on the ventral face, sometimes also dorsally.

Racemes 15-65-fld, the several expanded fls standing well below the narrow cone of developing fl-buds, the axis including short or obscure peduncle becoming 1-3(-3.5) dm; bracts firm, broadly ovate-triangular, densely gray-puberulent on both faces, before anthesis of fl deciduous together with 2 similar but smaller bracteoles; pedicels ascending or curved outward, at full anthesis 8-18 mm, the few fertile ones greatly thickened and lignified at maturity; buds ovoid obtuse, densely gray-puberulent; hypanthium not over 1 mm, often obscurely differentiated externally; sepals firm ovate- or oblong-elliptic obtuse, subhomomorphic except the 2 outermost a trifle shorter and wider, the 3 inner (6.5-)7- 11 mm, all early reflexed; petals yellow, widely spreading (12.5-) 13-20 mm, the blades beyond a short claw all oblanceolate or oblong-elliptic entire or those of the vexillar petal and sometimes of its two neighbors minutely auriculate at base; androecium glabrous, its members 4-morphic; the anthers of 3 long stamens erect, those of the rest resupinate; 3 abaxial antesepalous, sigmoidally curved filaments 20-24 mm, 2 abaxial antepetalous ones erect 6.5-9.5 mm, 3 adaxial antepetalous ones greatly dilated 3.5-6 x 1-1.7 mm, and 2 interposed between the last ±2 mm; anthers, in the same ab- to adaxially descending sequence, ovate 2-2.6 x 1.6-2.2 mm, 2.5-3 x 1.4-1.7 mm, 1.8-2.3 mm, and (shortest) sterile 0.6-0.9 mm diam; ovary densely pilosulous; style very short, the stigmatic cavity minute, looking obliquely upward and inward; ovules 70-98.

Pod pendulous cylindric or a trifle laterally compressed, when fully fertile up to 60 cm long, 2-2.5 cm diam, shallowly corrugated by constriction at the inter- seminal septa, the sutures scarcely elevated, the valves firm, at maturity dull blackish-brown or livid glabrate, the endocarp 0.5-1 mm thick, the stiff but thin septa ±0.2 mm in section, the seed-locules 6-10 mm long; seeds unknown.— Collections: 24.—Fig. 2 (pod).

Annually flooded riverbanks and varzea forest below 200 m, widespread in the centr. Amazon Basin in Amazonas and w. Para, Brazil, both on the great river and its affluents Negro, Jurua, Purus and Madeira, between ±54-68°W and 1-8°S.—Fl. III, V, VIII-XI, perhaps irregularly through the year, the pods maturing slowly and sometimes coeval with fls of another season.

A small crooked tree, described by Ducke (1939, p. 79) as common on backwaters and quiet lateral channels of the Amazon river system, one of several true cassias and sennas known locally as marimari. The flowers are bright yellow, fragrant, and the gelatinous pulp of the fruit is said to be bittersweet but edible.