S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 44

Diagnosis: Tubers are round, oval-rounded or long, of a wrong shape, slightly knobby with quite deep eyes, entirely red (skin is colored). Habitus of the plant is peculiar, different from caiceda, tocanum and from S. tuberosum.
Leaflets are usually small (rarely large), not narrow. Leaves have up to 6-7 pairs of leaflets, from which often one leaflet is not separated from the terminal leaflet has a “polupleshividnaja” shape, there are up to 3 pairs of primary leaflets in a series, often basiscopic, one pair of secondary leaflets, sometimes 1 pair of acroscopic.
Inflorescence is 2-branching (rarely 3-branching). Pedicle below articulation is about 20 mm (generally shorter than by caiceda), above articulation- (6) 8-9 mm. Articulation is colored. Pubescence is dense and short.
Calyx is 9-12 mm long, with narrow lobes, gradually tapering to the apex (different from  caiceda and S. tuberosum), slightly membranous, acumens are not big (1/3 of calyx length), about  4 mm long, deflexed. Calyx is bilabiate.
Corolla is weakly dissected, its petals are short, wide, corolla radius is big: 14-15 mm, minor radius is 10 mm, petal width is 17 mm, petal length is 6 (5-7) mm, length of acumen is 4 mm. Consequently, about 2 mm are left for the split which creates the impression of “demissoividnosti”. Corolla shape is clearly distinguishable from caiceda and ordinary S. tuberosum. Corolla color is lilac, petal tips are white; star is light, yellowish-green, wide. Corolla tube is not longer than the filaments, 2,25-2,5 mm.
Stamen filaments are yellow, 850-1170 µ thick, slim, long, 2,25 mm. Anthers are 6-7,25 mm, narrow, width of the basis is 2,5 mm, width of the apex is 1,75 mm, basis is not concave. Anther column is skewed, conic, chinked.
Style is not thick 520-580 micr., slightly thicker than by single accessions of caiceda (it equals in thickness to the sort Znicz (one of the slimmest among S. tuberosum)) at the beginning of the spiral it is curved und does not overtop the stems, afterwards it clearly overtops them and is inclined at the basis corresponding to the column displacement or twice, at the exit from the column. Stigma is big, not high, wide, sinus is not big. Berries are abundant, conic at the apex.
Cultivated in Columbia in dep. Boyaca: Cienaga; dep. Cundinamarca: Bogota; dep. Tolima: Ibague; dep. Caldas: Manizales.
Accessions №№ 28, 40, 43, 84, 91. (In flower composition there are characters close to S. Rybinii – bilabial calyx, sometimes very short calyx acumens, anthers, at first not outstanding style).
This form is the most early ripening and have a good yield among all Columbian varieties of S. andigenum, however in comparison with Chilian landraces this form has lower meaning of above mentioned characters.
Sexual progeny is very homogenous and is not much different from the main form, usually only in intensity of the color of corolla (up to its complete loss), articulation and tuber.
The name Londres (from London), which sometimes indicates this form, apparently, is accidental and does not have anything in common with the origin. It is doubtless a S. andigenum.