NO. 6 SMITHSONIAN EXPLORATIONS, 1914 41 



CACTUS INVESTIGATIONS IN PERU, BOLIVIA, AND CHILE 



Dr. J. N. Rose, associate in botany, U. S. National Museum (at 

 present connected with the Carnegie Institution of Washington in 

 the preparation of a monograph of the Cactaceae of America), spent 

 nearly six months in travel and field work on the west coast of South 

 America during the summer and fall of 1914, visiting Peru, Bolivia, 

 and Chile. He made collections on the coast at the following places : 

 Paita, Pacasmayo, Saliverry, and Mollendo in Peru ; Iquique, Anto- 

 fagasta, Coquimbo, Los Vilos, Los Molles, and Valparaiso in Chile. 

 As his chief work was to study and collect cacti, most of his time was 

 spent in the interior deserts. A section was made through central 

 Peru from Callao to Oroya, from sea level to the top of the Andes, 

 the highest point reached being 15,665 feet. Cacti were found in 

 the greatest abundance at an altitude of 5,000 to 7,500 feet ; but the 

 various species range from a few feet above sea-level to as high as 

 12,000 to 14,000 feet. 



A second section was made across southern Peru, from Mollendo 

 to Lake Titicaca via Arequipa. The highest point reached was 14,665 

 feet. Here also the cacti are found from near sea-level nearly to the 

 top of the Andes ; but the most remarkable display is on the hills 

 surrounding Arequipa, at an altitude of from 7,000 to 8,500 feet. 

 While the cacti are abundant in both these regions, they are, with 

 only a few possible exceptions, quite distinct. Side trips were made 

 from Arequipa to Juliaca and Cuzco, in Peru, and to La Paz, Oruro, 

 and Comanche, in Bolivia. 



On the pampa below Arequipa are found the famous crescent- 

 shaped sand dunes. Each dune or pile of sand is distinct in itself, 

 often separated some distance from any other dune, and occurring, 

 too, on rocky ground devoid of other sand. The dunes are found 

 on the high mesa some 5,250 feet above the sea. They form definite 

 regular piles of sand, each presenting a front 10 to 100 feet wide and 

 5 to 20 feet high, nearly perpendicular, crescent shaped, and from 

 the crescent-shaped ridge tapering back to the surface in the direction 

 from which the wind blows. These piles of shifting sand go forward 

 about 40 feet a year. 



In Chile two sections were made into the interior — one from 

 Antofagasta to Calama, and one from Valparaiso to Santiago. The 

 first is through the rainless deserts of northern Chile, the whole 

 region being practically devoid of all vegetation. The second is 

 across central Chile, the hills and valleys of which are veritable 



