S.M. Bukasov. Potatoes of South America and their breeding use, Leningrad, 1933, p. 36.

Diagnosis: Wide large leaflets, primary leaflets are very wide, rounded, not big, by adverse nutrition conditions leaves are weakly dissected with 4-5 pairs of leaflets, 1-2 pairs of primary leaflets  in a series and sometimes 1-2 pairs of secondary leaflets usually not basiscopic; in good conditions there are up to 6 pairs of leaflets; there are usually up to 3 pairs of primary leaflets in a series, sometimes 1 pair of acroscopic leaflets, always of a small size (differently from caiceda). In general, the leaf is less dissected than by f. caiceda.
Tubers have a correct form, oval, with small eyes, speckled to a different extent, colored parts are blurred, of a pale violet-blue color, usually not colored near the eyes. Sometimes, especially on young tubers, the color is very weak, tubers are almost white with a violet shade. Stem is almost green, with a small amount of anthocyan.
Peduncle is on the opposite of the stem leaf. Ears of the peduncle are almost up to 3 cm big. Inflorescence has sometimes 4-5 bostryxes. Pubescence of the pedicel is rare. Calyx is small, less than 1 cm long. It has 3 shorter sepals, 2 longer sepals, acumens in a bud are accumbent.
Corolla is very big (length of petals is 16-24 mm), lobe is more than a half of petal length, including the acumen about 4-5 mm long, shape of lobe is not inclined. Corolla color in the typical form is peculiar: dark violet (more pale-blue than by caiceda, also varying from f. lisarasa), star is a violet-black, with very long and branching rays. Corolla tube is bigger than 2 mm, slightly longer than stamen filaments.
Anthers are big, wide, 7-8 mm long, 2,5-3 mm wide at the base, width of apex is 2 mm. Stamen filaments are thin, 1100-1200 µ (the numbers characterizing thickness of stamen filaments, styles and papillae length in microns are outlined according to the data of A.V. Pigulevskiy), colored with anthocyan. Style is thin, 470-500 µ, long, 11,5 mm, inclined, it strongly overtops the stamens foor almost 4 mm. Stigma is not big, often with a deep linear thin interlobular sinus. Forms berries well.
Cultivated in Columbia, mainly on Bogota tableland, dep. Cundinamaraca - Bogota area: Chipaque, fontibon (№№ 38, 41а, 42а, 44, 49а, 76), rarely in Popayan (№ 106).
Indigenous names: Tocana, De ano, De la seja, Pana.
The name Tocana originates apparently from the place Tosa in dep. Boyaca on the height 2810 m above sea level. A synonymous name De la Seja indicates widespread forms in the "sekhi" area - seja de la montana.
It varies from f. caiceda in longer corolla petals, its peculiar color, wide large less dissected leaves (sometimes the stigma shape is different – it has a linear sinus).
It is distinct from the rest of Columbian forms together with Londres in an earlier and richer tuberization.