Colors of flowers, generally speaking, are due to anthocyan pigmnts — sometimes to carotenoids. Leaves most often owe their green to chlorophyll.
Fruit owe their reddish hues to carotenoids.
But what about other parts? A fascinating case is that of tubers. Since they grow underground, there is no need for pollination whatsoever. Hence, one may expect them to be devoid of color, a feature used to attract bird and insect pollinators.
A fascinating counter-example is that of potatoes, i.e., stem tubers. A visitor to an Andean country such as Peru cannot help noticing the brightly colored potatoes in open-air markets. In addition, due to their countless varieties, they are like paints on the palette of a painter. Brightly-colored as billiard balls, they also remind me of psychological assessments based on one’s color preferences, such as the Lüscher test, popular in the Seventies.
As one will recall, potatoes were discovered by Spaniards upon arrival in the New World and brought back to Europe. Cultivation of potatoes in South America may go back 10,000 years. In the Altiplano, potatoes provided the principal energy source for the Inca Empire, its predecessors, and its Spanish successor.
Nowadays, the Andes in Peru host many potatoes varieties. Many? Several dozens certainly, some claim thousands. Yellow potatoes, locally known as papas amarillas: the Amarilla Tumbay grown in the region of Cerro de Pasco, Huanuco, Junin and Lima and the Huagalina cultivated in the regions of Cajamarca, La Libertad, Ancash, Piura and Amazonas. Papas
Amarillas grow at an altitude between 2,800 m and 3,800 m above sea level.
The Qeqorani variety is grown in the regions of Cusco, Ayacucho and Huancavelica more than 3,900 m above sea level. Its flesh is yellow with patches of purple. Blue potatoes: Papa Leona is a variety cultivated in the regions of Cajamarca, Huancavelica, 3,000 m above sea level — the blue pigmentation is induced by the high intensity of UV light at such heights, as a
protection. Purple potatoes (papas púrpura): the skin and flesh of Papa Púrpura is of a deep purple, when cooked mostly bluish color. Pelargonidin- based anthocyanins give them the purple color. Black potato (papa negra): their skin is dark brown to black, the inside yellowish. It is known in France as the Vitelotte noire — the novelist Alexandre Dumas, a gourmet, preferred this variety to all other potatoes.