is still an ethnobotanical mystery (Ugent, 1970). Was it in Peru, Bolivia, or Chile that people first collected the bitter wild tubers and selected edible potatoes?
We traveled to the Peruvian city of Cuzco by way of a gravelly back road, which crossed the Andes east of Pisco and then traversed above Puquio the vast and unending altiplano, an arid tundra-like grassland called the puna. A cold 3,500 to 4,500 meters above sea level, and therefore often higher than Pike’s Peak, the puna is covered with a fantastic collection of cushion plants, including white fuzzy cacti that look like sleeping sheep, all adapted to withstand grazing by domesticated llamas and alpacas and the rare, wild vicuñas.
On the eastern slope of these gigantic mountains, within sight of snow-covered peaks, this so-called road (at times not much more than a footpath) dipped dizzily down from 4,260 meters to 1,800 meters at Abancay in only 25 kilometers, then crossed the Apurimac River below Curahuasi (where once stood The Bridge of San Luis Rey of Thornton Wilder’s novel), and eventually wound its way up again to the altiplano and on to Cuzco, the capital both of Inca kings and of wild and cultivated potato diversity.
A rest in Abancay was welcome after freezing nights tenting above timberline and being miserable with siroche (mountain or altitude sickness). On December 21, the early morning was spent packing some 1,500 dried herbarium specimens of the 296 different species collected the week before and getting ready for the push to reach Cuzco in time for Christmas and a hot bath. Then off we drove to the Hacienca Casinchihua in the Rio Pachachaca valley to look for a rare, wild potato species cited by Correll (1962) in a monograph published a short time before.
It was the beginning of the rainy season, and this deep valley was now bursting into bloom. Most memorable were pendent, 4-inch-long, orange trumpet flowers of a Mutisia, a gorgeous daisy named by Linnaeus’s son for the eighteenth-century Spanish botanist Don José Celestino Mutis.
Above the hacienda, our jeep was soon stopped by a landslide. There was nothing to do but hike along that old Inca road until high above the river we stopped to eat our lunch of avocados, oranges, cheese, and small, boiled Peruvian potatoes, yellow and rich in protein.
All around us was a floristic wonderland, full of rare and beautiful plants. In fact, these arid inter-Andean valleys are veritable biogeographic islands, each with many endemic (i.e., unique) species and isolated from other such valleys by wet tropical forests below and cold Andean tundras above, a situation favoring speciation and, hence, biodiversity. In a nearby gully, iridescent green and blue hummingbirds hovered and flitted about, piercing with their bills the cardinal-red flower tubes of a bushy sage, Salvia oppositifolia, one of several hundred (!) Andean species of this prolific genus.
So here we spent the rest of the day, always collecting five specimens of each plant—one each for the University of Wisconsin, the University of San Marcos in Lima, and the U.S. National Herbarium in Washington, D.C., and one or two for botanists specializing in that particular plant family, who would tell us exactly what we had collected. This must be done, for there are no accurate, usable books on the 30,000 species of Peruvian plants, a flora so rich it staggers the imagination.