S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 73.

Diagnosis: Tubers are oval, elongate, yellow with red eyes.
Berries are oval, elongate, very characteristic, apparently the longest among all the known forms of S. andigenum.
Has got many dirrerences from v. aymaranum: leaf is more basiscopic, character of pubescence is different, characteristic tightly pressed narrow conic anther column, big stigma, long berries.
Similarity with aymaranum: habitus (decumbent stems), wide oval leaflets, short pubescence, short pedicle below articulation, low situated articulation; good tuberization, like by the other forms of the variety.
Juz. № 1526, 1678 and other accessions (see Lechnovich).
Indigenous name "Coyo" .
Cevalos Tovar describes two varieties having the names with similar or close pronunciation Ccoyu (= morteado) and Coillu (= enganarse). Both varieties have got round tubers, white with flesh colored with anthocyan. Ccoyu has a dark-violet and very starchy flesh. Neither of the descriptions do correspond to the accessions of Juzepczuk under the name Coyo.