FOOD PLANTS OF ANCIENT AMERICA. 483 



of the Pacific were the scene of a former civilization much more 

 advanced than that found by Europeans. Seamanship, like other arts, 

 had declined, and communication with the remoter islands like Hawaii, 

 Easter Island, and New Zealand had been interrupted for several 

 centuries, perhaps as a result of an intermixture of the so-called 

 Melanesians, the native black race of New Guinea and neighboring 

 islands of the western Pacific, peoples inferior in agriculture, seaman- 

 ship, and social organization. In- spite of the richer native flora of 

 the Melanesian islands, nocultivated plant of importance seems to have 

 been domesticated there, no species being reported as in cultivation 

 among the Papuans which is not shared with the Malays to the west 

 or with the Polynesians to the east, and in nearly all cases with both. 

 The primitive agriculture of all the Pacific islands may be viewed, 

 then, as a connected whole, and a detailed study of the origins, present 

 distributions, native names, agricultui-al methods, and domestic uses 

 of the numerous species and varieties of cultivated plants may be 

 expected to yield the most definite information now obtainable regard- 

 ing the origins and migrations of the ancient agricultural peoples of 

 the Tropics.'* At present we have only incomplete and scattered data 

 collected incidentally by missionaries, ti-avelers, and pi'ofessional bot- 

 anists who did not appreciate their opportunities from the agricultural 

 point of view. But even these miscellaneous facts are often of unex- 

 pected interest. Thus, we know that in Central America the use of 

 leguminous shade trees in cacao plantations was adopted by the Span- 

 ish colonists from the natives, who furnished even the name, "mother 

 of cacao," by which the species of Erythrina and other leguminous 

 shade trees are still known in Spanish America. The Indians, of 

 course, were not aware that the roots of the leguminosae developed 

 tubercles for the accommodation of bacteria able to fix atmospheric 

 nitrogen in the soil, and thus increase its fertility. They believed 

 that the "madre de cacao" supplied water to the roots of the cacao, 

 a fanciful idea still credited by many planters, and not much improved 

 upon by the current notion that shade of large trees is beneficial to 

 cacao and coflfee. In the Pacific we encounter a similar fact with ref- 

 erence to the yam bean {Pachyrhizus), a leguminous vine with a fleshy 

 edible root. The natives of the Tonga Islands no longer cultivate 

 Pachyrhizus for food, but they nevertheless encourage its growth in 

 their fallow clearings in the belief that it rendei's them the sooner 

 capable of yielding larger crops of yams. Such anticipations of the 

 results of modern agricultural science are of extreme interest, but it 

 is still uncertain whether similar knowledge exists in other archipel- 

 agos of the Pacific, or on the American continent where Pachyrhizus 



"Even the cosmopolitan tropical weeds are worthy of careful study from this 

 standpoint. After excluding aquatic, swamp-land, and strand species, Seeman found 

 64 genuine weeds in Fiji, of which 48 were common to America, while only 16 were 

 held to be Old World species. 



