Picture the South American tropics: A small forest stream flows through the Ecuador lowlands near the town of San Domingo de los Colorados. The forest giants and lianas form a tunnel that arches above its shimmering surface. Its banks are covered with a dense growth of philodendrons, anthuriums and tree-ferns, with here and there the crowns of palms rising majestically above the surrounding vegetation. From the very first, however, our gaze is attracted to a spectacular plant growing by the riverside — Xanthosoma mafaffa. It is almost 2 m (6 ft) high and its large, heart-shaped ovate leaf blades, more than 75 cm (30 in) long, are a beautiful emerald green.
The genus Xanthosoma, numbering some 40 species, is to be found not only in South America, but also in Central America and neighbouring islands. The species is native to Guadeloupe, Jamaica, and Puerto Rico. It, too, is a large plant, the leaf blades often 50 cm (20 in) long. It is frequently grown in the tropics for its leaves, which are eaten as a vegetable. In Mexico, in the state of Veracruz, the large species X. robustum, which reaches a height of about 1.50 m (4 ft), is often encountered. Its huge leaf blades are up to 2 m (6 ft) long and nearly 1.50 m (4 ft) wide; they are used by the Indians like umbrellas to keep them from getting wet in the torrential downpours. The most beautiful of the lot, however, is X. lindenii of Colombia, which grows to a height of 75 cm (30 in) (tolerable, even if grown for room decoration); the leaf blades are about 40 cm (16 in) long, shield-shaped, and coloured deep green with a white midrib and principal veins.
Xanthosomas are tuberous plants that can be grown successfully only in a warm and sunny room. They are grown chiefly in a paludarium or indoor glass-case where it is possible to provide the necessary high atmospheric moisture. The compost should be light but nourishing — a mixture of peat, loam and sand. X. lindenii has the greatest heat requirements — a temperature of no less than 20°C (68°F) even in winter. The others do better if provided with slightly cooler conditions in winter. Propagation is by seed and by division of the clumps.