This attractive tree ranges from 25 to 50 ft (8-15 m) in height, has a dense, rounded crown, velvety hairs on its young branchlets, and copious milky latex. The evergreen leaves, clustered at the tips of small branches, are obovate, oval or elliptic, blunt at the apex, pointed at the base, 5 to 10 in (12.5-25 cm) long; thin or slightly leathery; dark-green on the upper surface, pale and sometimes brown-hairy on the underside. The profuse flowers, borne singly or 2 or 3 together in the leaf axils, are tubular, yellowish-green, with hairy sepals and 5- to 7-lobed mouth about 1/2 in (1.25 cm) across. The fruit is oblate, ovate or elliptic, pointed or depressed at the apex; 3 to 4 in (7.5-10 cm) long, with thin, delicate skin, brownish-green more or less overlaid with russet, and bright-yellow, firm, dry, mealy, very sweet pulp, permeated with latex until almost overripe. There may be 1 to 5, usually 2, rounded or broad-oval, dark-brown, glossy seeds with a whitish hilum on one flattish side.
The lucmo was first seen and reported by Europeans in Ecuador in 1531. Archaeologists have found it frequently depicted on ceramics at burial sites of the indigenous people of coastal Peru. It is native and cultivated in the highlands of western Chile and Peru and possibly southeastern Ecuador where it is known to have been cultivated since ancient times. It is grown also, to a limited extent, in the Andes of eastern Bolivia and the fruit is sold in the markets of La Paz. It is most popular in central Chile, less so in Ecuador. In 1776, it was reported as planted only in the warmest parts of northern Chile. In 1912, there were a few trees growing in gardens around San José, Costa Rica where the lucmo was introduced by returning exiles in the first half of the 19th Century. In 1915, O.F. Cook collected seeds at Ollantaytambo, Peru, for the United States Department of Agriculture (S.P.I. #41332). In January of 1922, Wilson Popenoe introduced seeds from Santiago, Chile (S.P.I. #54653). There have been several attempts to grow the tree in southern Florida. It has not lived long. One specimen actually bore fruit at the Fairchild Tropical Garden, developed galls, and eventually succumbed. The lucmo grows well in parts of Mexico and Hawaii but the fruit is not widely favored.
This species is not tropical, but grows at temperate elevations–between 9,000 and 10,000 ft (2,700-3,000 m) in Peru. It is adapted to fairly dry locations.
The tree blooms and fruits all year. Mature fruits fall to the ground but they are not edible until they have been kept on hand for several days. Peruvian Indians bury them in stored grain, cured hay, chaff, dry leaves or other materials until they become soft.
The fruit is eaten raw, out-of-hand, when fully ripe but Costa Ricans find that, though the flavor is appealing at first, one soon finds it repulsive because of the peculiar aftertaste. The lucmo has been stewed in sirup, used as pie-filling, and made into preserves. Currently, some fruits are being shipped from Chile to England where they are being used in making ice cream. A dehydrated, powdered product is being produced by a tomato cannery in Peru.
The wood is pale, compact, durable, and used for construction in Peru.