S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 56.

Diagnosis: Tubers are much-faceted, characteristically small-spotted. Leaf is 5-paired, 2 of the pairs are smaller, one pair of primary leaflets. Leaflets are of a small size, wide, shiny.
Pedicle is colored, length above articulation is 5-7 mm, below articulation 12-15 mm, articulation is small. Pubescence is short, dense, pressed.
Few flowers. Calyx is green with colored veins, small, length (6)7 mm, out of them mucronule = 2 mm, bilabiate.
Corolla radius 15 mm, petal 7, acumen 3 mm, petal is small, acumen is pubescent. Lilac color, star is half-dark, white apexes at the top and at the bottom are small. Stamen filaments are thick, 1,5 mm long, 3 mm from corolla margin, anthers are small 5-5,5 mm. Style is 10,5 mm long with visible papillae. Stigma is small, very law (of the type S. Rybinii? Not bigger?) slightly 3-separated. Ovary is 3-nested, wide egg-shaped with 3 clearer and 3 less clear vallecula , situated like calyx lobes.
Juz. № 1352 from Soncco Huichay, 1326c from Ccaira and others.
In sexual progeny № 1362 segregation is weak and parent type dominates. Deviations are present in the calyx flatness, shape of its lobes and shape of anther column. Сcompetillo is close to v. Ckello huaccoto in leaf dissection and corolla color, it is different in weak corolla dissection. It is close to Taccla in habitus, but is more powerful.
Other indigenous names: Puca mama, ocke tccomera.