Description. Mauka is a low, compact plant, not exceeding 1 m in height. The aerial part is a mass of foliage formed from the basal shoots. The stems are cylindrical, with opposite, ovoid leaves with reddish edges. Bolivian types seem to have uniformly purple flowers, but in Ecuador they range towards white. The inflorescences are terminal racemes covered with viscid hairs, to which small insects frequently become stuck.
The thickened stems below ground are white, salmon colored, or yellow. They are commonly smooth and fleshy, about 5 cm in diameter and 50 cm in length. The growth takes place on the outer surfaces, and the structure of the stem becomes more regular toward the cream-colored center, which is high in moisture, full of starch grains, and contains little fiber. The form preferred in Cajamarca has yellow skin with cream-colored flesh. The color may depend on age, young tubers being yellow and older ones being white.
Horticultural Varieties. There are no defined varieties, but there are different genotypes. In Bolivia, as noted, mauka has purple flowers and astringent tubers. In Ecuador, a full gradient of flower color from purple to white may exist, and not all tubers are bitter.
Rainfall. Mauka seems to survive in wet, cold areas as well as in seasonably arid regions. The limits of its moisture tolerance are unknown. However, in Cajamarca it thrives at 600-1,000 mm per year.
Altitude. Reported from 2,200 to perhaps 3,500 m within the central Andes. However, it has not yet been tested at other elevations.
Low Temperature. Unknown, although the plant may not be frost tolerant.
High Temperature. Unknown. The plant is probably sensitive to heat.
Soil. Not unexpectedly, mauka seems to yield best in loose, alluvial soils. The limits of its soil tolerances are unknown.