S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 58.

Diagnosis: C var. sihuanum has some common characters, in general a distant form, maybe a variety, f. chimaco (hybrid with ckello?).
Similar to var. sihuanum in width of leaflets, short pubescence and shape of calyx with deflected mucronules, shape of tubers.
Similar to v. ckello-huaccoto in short stamen filaments and conic anther column.
Differences from v. sihuanum – a more decumbent stem, leaflets are not basiscopic, shape of corolla acumens is different, corolla is colored more intensively with some stronger expressed violet shade, stamen filaments are shorter, stems are longer, anther column is conic, style is less outstanding, stigma is shorter and wider.
Differences by 1323 (1325?) from Ckello are the following: leaf, peculiar very short outstanding pubescence, narrow strongly deflexed mucronules, less sloping corolla petals, small stigma.
Does not form berries.
Cultivated in Urubamba area: Ollantaytambo (Juz. № 1064) and in the region Acomayo: Pomacanchi (Juz. № 1186).
Indigenous names: chimaco, ckehuilo.
Herera chimaco has elongated tubers of a very good quality, this is an early cultivar. Ccehuillo has bitter tubers, bent, like Chuno sort. Consequently, the names given are not synonyms.