Potato (Solanum tuberosum)

node · earth · Andean origin; Europe, Asia and Africa by transfer

A tuber domesticated in the Andes, where hundreds of landraces are grown across a range of altitudes, and the crop with the strongest claim to have changed European demography. Its advantage was ecological rather than culinary: it yields heavily on cool, wet, acid, marginal ground where wheat and rye do poorly, it stores through a northern winter, and it produces far more calories per hectare than the cereals it supplemented. It also arrived as a botanical curiosity rather than a food — early European references are to gardens and herbals — and took the better part of two centuries to become a staple, held back by suspicion of a nightshade and by the poor adaptation of early Andean short-day varieties to European daylengths. Its eventual dominance in some regions produced a corresponding fragility: a crop propagated clonally from a narrow founding stock met Phytophthora infestans in the 1840s with almost no genetic defence, and the consequence in Ireland was catastrophic.