Flora of Barro Colorado Island

Manihot esculenta

Crantz, Inst. Rei Herb. 1:167.1766

Yuca, Cassava

Glabrous, monoecious shrub, l-3 m tall; stems with milky sap. Leaves alternate, simple; stipules lanceolate, acuminate, 7-8 mm long, deciduous; petioles to 12 (17) cm long; blades deeply lobed, acuminate, 8-12 (17) cm long, 1-3.5 (5) cm wide, glaucous below, the lobes 3-5 (7), narrowly elliptic. Panicles axillary and terminal, to 10 cm long in flower, longer in fruit; staminate flowers racemose along main axis; pedicels 4-6 mm long; calyx campanu­late, 3-7 mm long, yellowish-green, 5-lobed, puberulent on outside; petals lacking; disk ca 2 mm wide; stamens 10; filaments to 12 mm long, unequal; anthers ca 2 mm long; pistillode lacking; pistillate flowers several along basal branches; pedicels slender and 7-12 mm in flower, stout and to 17 mm in fruit; calyx 5-lobed to near middle, to 10 mm long; petals lacking; disk ca 3 mm wide; ovary 6-winged or 6-ribbed; styles three, ca 2 mm long, dilated and divided into capitate tips. Capsules subglobose, 1.5-2 cm long, 6-ribbed; seeds 3, compressed, ca 9 mm long and 6 mm wide, smooth, with a darker beak at apex. Croat 7248.

Cultivated in the Laboratory Clearing. Seasonal be­havior uncertain. Flowers at least from October to     January, with mature fruits known from January and July. Plant tissues contain hydrocyanic acid (Blohm, 1962). Apparently native to South America (Brazil), but widely cultivated in the tropics. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, San Blas, and Darien.