S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 59.
Diagnosis: Similar to v. sihuanum in long stamen filaments and almost straight anther tube on elder flowers.
Differences: longer calyx pubescence, longer calyx, corolla with shorter and inclinated petals, light-violet, anthers are longer, with a less sinuate basis, style is less outstanding, berries are less long, oval, numerous. Stigma is compressed. Ņuberization among S. andigenum is good.
Cultivated most often under the name Tumbo in dep. Cuzco: in Paucartambo (Juz. ¹1328, indigenous name is ocke salle, 1348, ķąēā. misquilla de saucant), Patabamba (Juz. ¹¹ 1252, 1252), Ckeccayoc (Juz. ¹¹ 1334, 1361ā), Yana machai (Juz. ¹ 1276), Sihua (Juz. 1259c); Rayancancha near Ollantaytambo (Juz. ¹ 1053).
In reproductive progeny ¹ 1276 calyx lobes vary strongly, the form of mucronules varies from small leaf-shaped till big of the type S. mamilliferum, sometimes narrow. The form of anther tube also varies strongly. Strong variation of these characters can be a consequence of hybrid nature of this form.