Synonyms Ullucus tuberosus Loz., Ullucus kunthii Moq., Basella tuberosa HBK; Melloca tuberosa Lindl. and Melloca peruviana Lindl.12
Aymara: ulluma, ullucu
Spanish: melloco (Ecuador), olluco, ulluco, rubas (Colombia, Ecuador); rubia, ruba, tiquiño, timbós, mucuchi, michuri, michiruí migurí (Venezuela); camarones de tierra, ruhuas, hubas, chuguas, chigua (Colombia); papa lisas, lisas, olluco, ulluco (Peru, Bolivia); olloco, ulluca, ulluma (Argentina); papa lisa (Peru, Spain)
English: ulluco, melloco
Origin. Ulluco is a completely domesticated crop. It is often represented in pre-Columbian art, and tubers have been found in 4,250-year-old ruins in coastal Peru—far from the area in which it currently grows.
Wild forms (for instance, Ullucus tuberosus subsp. aborigineus Brücher) occur in Peru, Bolivia, and northern Argentina. They are mostly vinelike, with long internodes and reddish stems. Their spherical white, pink, or magenta tubers are about the size of small peas or marbles, and are more bitter than those of domesticated varieties.
Description. Ulluco is a low-growing herb. All parts are succulent and mucilaginous. On long petioles from the angular stem are borne alternate, heart-shaped leaves, the color of which depends upon the cultivar. Wild forms are prostrate. Cultivated forms come in a gradient of types from prostrate or semiclimbing vines to dense, compact, bushlike mounds up to 50 cm tall.
The small, green-yellow to reddish flowers are borne in clusters arising from the forks of the branches. Seed set has never been shown in either wild or cultivated forms in the Andes.13
The plant forms tubers on long stolons both below and above the ground. Most arise below ground from the mass of fibrous roots, the ends of which thicken and swell.
The tuber skin is thin and soft, with inconspicuous buds. Cultivated tubers can be elongated (2–15 cm) or curved. Some in southern Colombia are as big as normal potatoes. The most common are spherical and lemon yellow. However, coloration may be white, pink, orange, red, or magenta—a common, popular form has magenta spots speckled on a yellow background. Inside, the tubers are yellow or