HISTORY AND PROBLEMS 17 
study. Planted usually on land that has received some flood water, 
the soil is cleared for planting. Holes are dug with a stick down to 
moist soil and 1§ to 20 grains of maize are dropped in the hole. 
Although ordinary varieties of maize cannot reach the surface if 
planted over 3 inches deep, Hopi maize because of a greatly 
elongated hypocotyl can be planted as much as 14 inches under 
ground. Whereas ordinary maize develops three roots from the 
seed, Hopi maize develops only one, which can be pushed deep 
into the soil in search of moisture. These two adjustments make 
Hopi maize superior to other varieties in an arid environment. A 
hill of dense stems protected at first by a rock and later by many 
leaves is not easily damaged by drifting sand. Planted 6 to 8 
feet apart the roots can slowly elongate into a large soil mass 
available to them. Beans are next in importance, and squash and 
melons are grown without irrigation. Peaches and a few apricots 
and apples are grown on the sand hills. The Hopi also irrigate 
land when and where water is available. Here onions, chili, wheat, 
sorghum, tomatoes, potatoes, grapes, garlic, cucumbers, tobacco, 
and false saffron are grown. The tepary beans were domesticated 
in prehistorical time and are now important crops of this region. 
To primitive man one great advantage of the arid zone was the 
ease of curing and preserving food in the dry air. Seeds can be 
stored and such plants as squash and melons cut into strips and 
dried to be kept for future use. 
The use of all features of the natural environment by primitive 
man is well illustrated in South Africa where the Bushmen and 
Hottentots depended so largely on the fruits of the mtsama melon, 
the wild watermelon, an annual plant which gathers moisture 
from the desert soils during the growing season and stores it in 
the small thick rind melons which hold it for months. The melons 
could be cached in the desert sands and used largely as a water 
supply when needed. Travel in the Kalahari was possible only 
when this source of water was available. Again in the extremely 
dry Southwestern African desert the Acanthosicyos horrida, a 
shrublike spiny cucurbit, furnishes in its large fruits both water 
and valuable oil seeds for food and drink when no other water is 
available. The barrel cactus serves as a like source of water in 
