STAIRCASE FARMS OF THE ANCIENTS 



515 



of the plants. Of some of them even 

 botanical information is lacking. Indeed, 

 it may be said that knowledge of some of 

 these plants has actually declined since 

 the time of the conquest. 



The account of Peruvian economic 

 plants written by Padre Cobo less than 

 70 years after the conquest is still the 

 most extensive and detailed work on the 

 subject. 



OTHER PERUVIAN ROOT CROPS 



The agriculture of Peru is based on 

 root crops, primarily. Seed crops are 

 relatively few, and, with the exception of 

 corn, are almost incidental to the numer- 

 ous root crops. Even corn is used largely 

 for making chicha rather than for food, 

 especially in many districts at higher ele- 

 vations, where potatoes are the chief arti- 

 cle of diet. 



In order to understand the domestica- 

 tion of many root crops in Peru, it is 

 necessary to go back to a pre-agricultural 

 or an extremely primitive agricultural 

 state, when people subsisted entirely or 

 very largely upon wild roots, and resorted 

 every year to the gathering of these, in- 

 stead of being able to rely entirely upon 

 the products of cultivated land, as in a 

 more advanced state of agricultural de- 

 velopment. With agriculture developed 

 to the point of complete independence of 

 the wild-food materials, no more domesti- 

 cations of food plants are likely to be 

 made, as none seem to have been made 

 during the entire historical period of 

 civilized European agriculture. 



From eating a great number of plants, 

 as the wandering savages do, agricultural 

 man gradually becomes restricted by 

 habit to the foods that are produced by 

 cultivation, and he finally reaches a stage 

 where the idea of going out and bringing 

 in a wild plant to cultivate as food is en- 

 tirely foreign to the mind. To the pres- 

 ent-day Indians of Peru the cultivated 

 food plants represent a perfectly distinct 

 and definite class. The plants that are 

 sown are sown, and the plants that are 

 wild are wild. They accept as a matter 

 of course that there are wild potatoes, 

 wild ocas, wild anus, wild arracachas, 

 wild achiras, and so on down the list ; but 

 it is not supposed that these have any- 



thing to do with the cultivated forms of 

 the same types, or that anybody would be 

 foolish enough to plant the wild kinds 

 and expect to raise crops from them. 



If any more plants are domesticated in 

 Peru, the Indians are not likely to do it — 

 that is, for their own use. If some hew 

 crop should be introduced by the white 

 people, or if a demand should arise for 

 the product of a wild plant that could be 

 cultivated easily, the Indians might go to 

 planting it, for their agricultural habits 

 and instincts are highly developed ; but 

 either of these contingencies is very dif- 

 ferent from a spontaneous domestication 

 of a new native food plant on their own 

 initiative and for their own use. 



In the alpine or Andine belt, where the 

 potato is the chief crop, three other root 

 crops are generally grown, by the same 

 methods and often in the same rows with 

 the potatoes. These Andine root crops 

 are the oca (Oxalis tuberosa), the arm 

 (TropcEolum tuberosum, page 526), and 

 the ullucu (Ullucus tuberosus). The 

 tubers of all of these plants are remark- 

 ably alike and similar to some of the 

 varieties of potatoes, although the plants 

 have no relation to potatoes or to each 

 other. The oca is a relative of our sheep 

 sorrel, the ami of the common flowering 

 nasturtium, and the ullucu of the Ma- 

 deira vine. Though not attaining the size 

 of large potatoes, the other tubers are 

 more attractive in appearance and seem 

 to have even better keeping qualities. 



The possibility of utilizing them in the 

 cooler parts of the United States is 

 worthy of careful consideration. Their 

 value might lie, as in Peru, in supple- 

 menting the potato, and thus affording a 

 more varied vegetable diet. They yield 

 well and are easily grown. Though na- 

 tives of a tropical country, these crops 

 are found only in the cool elevated dis- 

 tricts and are, like the potato, intolerant 

 of high temperatures. 



In the lower part of the potato belt 

 there is another root crop — the yacon or 

 llacon (Polymnia sonchifolid) — compar- 

 able to the so-called "Jerusalem" arti- 

 choke, which is supposed to be a native 

 of Mexico. It produces large, compact 

 clusters of thick, fleshy roots tapering at 

 both ends and with a stronsr external re- 



