Journal of Heredity 16(3): 95-110 (March, 1925)
PERU AS A CENTER OF DOMESTICATION
Tracing the Origin of Civilization Through the Domesticated Plants
(Continued from the February Issue)
O. F. COOK
U. S. Department of Agriculture

A SORREL ROOT CROP
Figure 8
The oca (Oxalis tuberosum) is one of the four high altitude root crops, less important than the potato, but more important than the anyu or the ullucu. The taste of the raw tubers is acid like sheep sorrel, but they become sweeter when exposed to cold weather. Ocas, like potatoes, are preserved by freezing and drying.
A TERRACED VALLEY IN THE ANDES
Figure 9
This is a view of the valley above Ollantaytambo, on the eastern side of the Andes, one of the chief centers of pre-Inca culture in Peru. The entire valley bottom was reclaimed by the ancient colonists, who must have planned and laid out the terraces before the land was occupied. Note the ruined building high up on the cliff on the right. The purpose for which this was used is not known. Possibly it was a storehouse, rather than a nunnery, as has been suggested. On the steeper slopes in the middle distance can be seen the almost obliterated remains of some of the ancient terraces that have been long abandoned.

Endemic Crop Plants of the Peruvian Region

ORIGINS and places of domestication are difficult to trace with plants that are widely distributed in cultivation but of which no recognized wild type is known, as in the case of maize, and difficult also with plants that escape readily from cultivation and grow spontaneously in different parts of the world. But in Peru there are many domesticated plants whose origin is hardly to be questioned, since their cultivation has not extended to other regions. Also most of the endemic crop plants of Peru are to be found growing wild, or are closely related to wild species of the same region. Obviously, there is no reason to seek elsewhere for the center of domestication of such endemic species. Certainly no other part of America can compete with the Peruvian region in the number of endemic crop plants, some of them prominent, like the potato, the chirimoya and the coca or cocaine plant, while many others are scarcely known outside of Peru.

PERUVIAN POTATO VARIETIES
Figure 10
ROOTS OF THE PAPA LISA
Figure 11
The potato is the most valuable of the gifts that the ancient Peruvians made to the agriculture of the world. One year's potato crop amounts to from four to six billion bushels, which represents in money value probably far more than the treasure taken from Peru at the time of the conquest. In spite of this, the potato is not an unmixed blessing, for by making possible a greatly increased population in northern Europe it is to be regarded as one of the contributing causes of the World War. These are not potatoes, but represent three varieties of the ullucu or papa lisa, a root-crop of the highlands of Peru. The plant is related to the familiar Madeira vine, of the family Basellaceae. Papa lisas are usually cooked with potatoes as an ingredient of soups or stews. The varieties differ greatly in shape and size as well as in color, ranging from white to yellow, pink, and red.

The significance of the endemic plants, as marking a center of domestication, has been overlooked. With some of the special writers on Peru, the distinctive local products have almost monopolized attention, while the other plants that were shared by Peru with other parts of tropical America have been disregarded as though having no relation to the endemic series. Though nobody would deny that the endemic crop plants were domesticated in the Peruvian region, the prepossession toward Mexico makes it possible to assume that the widely distributed plants, such as Indian corn, sweet potatoes, peppers, and peanuts were carried to Peru from Mexico or from the West Indies. To some writers this idea, that the plants were carried to Peru, has been suggested by the fact that the early Spanish explorers learned the names and uses of many of the American crop plants before Peru was discovered, and several such names were carried to Peru, already incorporated in the Spanish language.

Native Peruvian Plant Names

Since the identification of genuine native names is probably the best evidence of the existence of the plants in Peru in pre-Spanish times, it is worth while to place on record a list of the native Peruvian names of the cultivated species, mostly derived from the so-called Quichua or Inca language. Some of the native Peruvian plant names have been replaced almost completely by West Indian or Mexican names brought in by the Spaniards, like maiz for Indian corn, mani for the peanut, and camote for the sweet potato, but the native language of Peru is still spoken by millions of people. Most of the Peruvian names that were recorded in the early days by Cobo and other writers are still current, at least locally, in some of the valleys of the Andes. No doubt some names remain to be discovered, and other species or varieties of plants probably are hidden in remote valleys.

Some of the names are handed down from early Spanish writers, and some have not been found in previous publications, but seem to have been recorded for the first time in 1915, during a joint expedition of Yale University and the National Geographic Society, in cooperation with the Department of Agriculture. Some plants have several names, referring to different varieties or to different parts that are used, while some plants that appear to be thoroughly indigenous are yet to be associated with genuine native names. The number of native cultivated plants may be estimated safely between seventy and eighty species. The series no doubt is incomplete, and the applications of some of the names are rather uncertain, but at least a preliminary list should be available as a basis of further discussion. The list no doubt could be extended greatly on the side of ornamental and medicinal plants, shrubs and trees, many of which have a status of partial cultivation, but only the more important of such species are included. Similarity to Mexican names may be noted in some cases, as achihuiti, lacayote and suchi, but the origins need to be definitely determined. Names of several types of beans, peppers, squashes, gourds and passion-fruits are included, but not the names of the many varieties of potatoes and other root-crops, which probably would double the list.

List of Names of Domesticated Plants in Peru

Peruvian Name Genus. Spanish and English Names
Abinca (Cucurbita) squashes with hairy seeds.
Achira (Canna) a warm-temperate root-crop.
Achocjche (Cyclanthera) cayguas, a climbing vine with an edible fruit.
Achupalla (Ananas) pina, pineapple.
Ajipa (Cacara) jicama, yam-bean, a root-crop eaten raw.
Amancay (Amaryllis) a favorite flower.
Amarucachu (Polianthes) tuberose.
Ancara (Lagenaria) calabaza, calabash.
Anyu (Tropaeolum) a high altitude root crop.
Apichu (Ipomoea) camote, sweet potato, the sweet varieties.
Apincoya (Passiflora) grandilla, the large passion-fruit.
Aricona or Aricuma (Polymnia) see llacon.
Arracacha (Arracacia) apio, a temperate-region root-crop.
Ayauasca (Banisteria) a low-land intoxicant.
Ayrampu (Opuntia) small cactus used for dye.
Cachuma or Cachun (Solanum muricatum) pepino, an edible fruit.
Cantu (Cantua) flor del Inca, flower of the Inca.
Canyihua (Chenopodium) a high-altitude seed crop.
Caya (Oxalis) also written kahuy, dried ocas.
Chachacoma (Escallonia) a high-altitude tree, the wood used for carving.
Chinchi (Capsicum) aji, cayenne pepper.
Chirimoya (Annona) a temperate-region fruit.
Chonta (Guilielma) a palm with edible fruits, some varieties seedless.
Chuchao (Frucraea) an important fiber plant, generally growing wild.
Chunyo (Solanum) papa, potatoes frozen and dried black.
Chuy (Phasaeolus) frejol, bean.
Coca (Erythroxylum) the cocaine shrub.
Cocopa (Solanum) dried potatoes.
Cohuacho (Cucurbita) squashes with small white seeds.
Coimi (Amarantus) see also quichuicha.
Cullash (Schinus) mulli, pepper tree.
Cumara (Ipomoea) camote, sweet potato, the starchy varieties.
Cuyuy (Ruda?) used as pot-herb.
Huacatay (Tagetes) used as pot-herb.
Huantuc (Datura) used as intoxicant.
Huayau (Salix?) sauce, a fastigiate willow often planted.
Huillca (Piptadenia) a leguminous tree, medicinal and intoxicant.
Huitocj (Genipa) a tree of the warm eastern valleys, valued as a medicine.
Inchis (Arachis) man] , peanut, with only one seed in a pod.
Jataco (Amarantus) seed-crop of temperate regions.
Lacayote (Cucurbita) squashes with black seeds.
Lambran or Ramran (Alnus) aliso, alder.
Marcu (Ambrosia) used as pot-herb.
Masasamba (Annona) guanabana, soursop.
Matti (Lagenaria) the bottle gourd.
Moray (Solanum) potatoes frozen, soaked and dried, white like chalk.
Mulli (Schinus) "pepper tree" of California, native of the Andes.
Nucjchu (Salvia) with pendent scarlet flowers.
Oca (Oxalis) an important root-crop.
Pacay (Inga) a tree with edible pulp surrounding the beans.
Pacjpa (Furcraea) wrongly called "maguey."
Pallor (Phaeaeolus) Lima bean.
Palta (Persea) aguacate, avocado.
Pamuco (Crescentia) the calabush tree.
Pante (Polymnia?) a root crop similar to Ilacon, but smaller.
Papa (Solanum) papa, Irish potato.
Papaya (Carica) papaya, pawpaw, two species planted.
Payco (Chenopodium) used as a pot-herb.
Pirca? (Lycopersicum and
Cyphomandra)
tomato, cultivated and wild species.
Piris (Capsicum) a small variety.
Pischic (Sambucus) sauco, elder-berry, a tree of the eastern Andes.
Pisonay (Erythrina) tree with scarlet flowers.
Poro or Puru (Lagenaria) the bottle gourd.
Purush (Passiflora) a passion-fruit.
Purutu (Phasaeolus) frejol, bean.
Quenuar (Polylepis) a high-altitude tree.
Quihuicha (Amarantus) a temperate-region seed crop.
Quinoa or Quihina (Chenopodium) a high-altitude seed crop.
Quisuar (Buddleia) a high-altitude tree.
Racacha (Arracacia) see arracacha.
Rocoto (Capsicum) chili, cayenne pepper.
Rucma (Lucuma) see lusma.
Rumu (Manihot) yuca, cassava, the chief tropical root-crop.
Sahuinto (Psidium) guayava, guava.
Sapallu (Cucurbita) calabaza, squash, many varieties, also wild.
Sara (Zea) mais, Indian corn, Cuzco type, with sweet and pop varieties.
Sara sara (Paspalum) maisillo, a grass cultivated for forage.
Sayri (Nicotiana) tobacco, also called camasayre.
Suchi (Plumieria) frangipani, a small ornamental tree.
Sulloco (Sapindus) soap berry.
Tara (Caesalpinia) C. pectinata, used for dye.
Tarhui (Lupinus) altramuz, cultivated for its seeds, which are eaten.
Tintin (Tacsonia) a passion-fruit, broadly rounded, flattened at the end.
Tumbo (Tacsonia) a passion-fruit, long-elliptic, pubescent, sour.
Uchu (Capsicum) general name for peppers.
Ullucu (Ullucus) papa lisa, a root crop.
Uncucha (Xanthosoma) a tropical root-crop, also dried to make chunyos.
Unguna (Curcuma?) a root-crop.
Usum (Prunus) capuli, the Andean cherry.
Utcu (Gossypium) algodon, cotton, the "rough Peruvian" type.
Yacon (Polymnia) see llacon.

Crop Plants of Extra-Peruvian Origin

Though it would not be reasonable to ascribe definitely to the Peruvian region all of the plants that were shared by the ancient Peruvians with other parts of America, neither is it reasonable to assign these plants to other regions without requiring evidence that they did not come originally from Peru. The only safe way is to disregard temporarily the plants that were shared by Peru with the other regions, and give our attention to plants that seem not to have been known in the Peruvian region in ancient times, and thus may be considered as extra-Peruvian. From the paucity of such extra-Peruvian species it appears that no other center of plant domestication was comparable in importance with the Peruvian region.

Reckoning seventy species of plants is cultivated in Peru in pre-Spanish times, and at least half of these as definitely endemic or confined to that region, the status of Peru as a center of domestication would seem to be established.

Other Centers of Domestication

The highest developments of the culture of extra-Peruvian plants undoubtedly were those of the cacao in Guatemala and southern Mexico, and of the pulque agave in the Mexican table-land. The Central American avocado no doubt is a native tree but is scarcely to be considered as a cultivated crop, among the native population. Other Central American domestications were garden plants, as chayote (Sechium), chia (Salvia), and the chiltomate, a species of Physalis. Calathea and Dioscorea may have been cultivated to a slight extent in the West Indies, though this is doubtful. The cassava, sweet potato, and yautia (Xanthosoma) were grown in the West Indies, and arracacia has been found recently in the mountains of northern Haiti.

Only two secondary centers of domestication are indicated, one perhaps in the Maya districts of Guatemala to account for cacao which is a low-land tropical tree, and another in the table-lands to account for the pulque agave and other plateau cultivations. But all of the Central American or Mexican domestications appear to be secondary and incidental to the existence of people who lived by milpa agriculture as in the lower valleys of Peru. The table-land agriculture of Peru was the striking, peculiar development, while the agriculture of the lower elevations was essentially the same in Peru as in other parts of tropical America. Nowhere in America does there appear to have been an extra-Peruvian agriculture, where people subsisted regularly or chiefly on crops that the ancient Peruvians did not have.

Of course, it is possible to assert that the agriculture of the lower valleys of Peru came from Mexico or elsewhere, and received a special elaboration in Peru, on account of peculiar conditions, but certainly the question should not be prejudiced in advance by casual assertion. The conditions in Peru should be studied to see whether they were specially favorable for domestication, and for developing specialized agricultural arts, whether more of the ancestral forms of the cultivated plants can be found in the Peruvian region, and whether the movements of the native races radiated from Peru as a center, or from some other region. Such questions may be followed by students of the physical characters, languages, customs, arts or ancient remains of native peoples of South and North America.

Conditions of Domestication in Peru

Domestication should be studied from the standpoint of biological or ecological conditions, and especially the primary domestications of foodplants. That so many plants were domesticated in Peru suggests that the people must have had a special talent for agriculture or that the conditions in some way were especially favorable. Such conditions may be found in hundreds of narrow precipitous valleys, often a mile deep, cutting through the highest chain of the Andes.

Primitive people who might enter and establish themselves in such valleys would find their movements restricted and their means of subsistance narrowed to the products of one district. Thus there would be ample opportunity and incentive for careful search and trial of any food possibilities of the native flora, and for the taking of the first step in cultivation, by pulling the useless cora, which we call weeds, to let the food plants grow. Greater pressure on the means of subsistence would carry the people gradually to habits of more intensive cultivation, by clearing the ground completely of other growth and using sprouts, tubers or seeds to propagate the useful species.

Among the historical writers, Payne was almost alone in developing a practical idea of the conditions that would be favorable for leading a primitive people to domesticate plants and adopt the habits of a settled agricultural existence.

"In order that cultivation may become permanent there must be a concurrence of the opposite conditions—a concentration of population within separate and limited areas, separated it may be, from each other by tract which yield no food at all: …"

*Staircase Farms of the Ancients. National Geographic Magazine, May, 1916.

These conditions are met in the most definite and striking way in the narrow deep valleys of the eastern Andes. Payne, however, was some what misled by the idea of a primitive pastoral state, and considered the table-lands as the original scene development of the Peruvian system In contrast with the deep-cut valleys of the eastern Andes the Peruvian table-lands are a succession of broad gently sloping valleys, readily accessible open grassy country, not favorable to agriculture and not affording the definitely circumscribed conditions that would lead a wandering shepherd people to adopt a settled existence. Though the ancient civilization attained a higher, development in the upper valleys and on the tablelands, these lower valleys may have witnessed the first steps of progress toward an agricultural state. Notwithstanding the wide range of conditions and the numerous plants that were domesticated, the system of agriculture seems continuous and complete, as though the same race of people had adapted themselves gradually to the conditions of the higher valleys, many of which appear to have been planned and developed as reclamation projects.*

AN EDIBLE CANNA
Figure 12
A NASTURTIUM ROOT CROP
Figure 13
This plant, called Achira in Peru, is much like our familiar ornamental varieties of canna, but with rather small flowers. The roots are boiled and have a sweetish taste, but are very fibrous and much inferior to sweet potatoes. The anyu, a root crop grown at high altitudes, with the potato, the oca and the ullucu. The plant is a species of Tropaeolum closely related to Tropaeolum majus, the common Nasturtium of our gardens.

Domestication of Animals in Peru

In addition to the domestication of numerous high-altitude crop-plants, at least four kinds of animals were domesticated in ancient Peru, the llama, the alpaca, the guinea-pig (cuy or cohui) and two or more species of dogs. The llama and alpaca furnished wool and served as pack animals, the only native beasts of burden in the New World. The cuys are kept in the houses and seem to be more thoroughly domesticated than any other animal. Only the cuy is generally distributed among the natives of Peru, the llamas and alpacas being kept only at the higher altitudes, seldom below 12,000 feet. A species of duck was also probably domesticated and the cochineal insect was used as a dye, which still appears in the native markets under the name macnu.

Elsewhere in America the only regular domestication of an animal seems to have been that of the turkey in Central America, aside from the dogs which were generally distributed, and may have been adopted in a pre-agricultural age.

+Foot-Plow Agriculture in Peru, Smithsonian report for 1918, Pages 487, 491.

The llama and alpaca may be only different varieties of the wild huanaco. Though members of the camel family, their habits and uses are closely analagous to those of sheep in the Old World, to furnish wool and meat. The male llamas also carry burdens, but do not serve as draft animals, so that all of the agricultural work is done by hand, even in the higher altitudes where tough sod-land is broken by hand labor for planting potatoes.+

The greater resemblance to European agriculture resulting from the use of domestic animals and of woolen clothing in the high altitudes of Peru has led Payne and several other writers to consider the Peruvian tablelands as the original seat of agriculture in America, or at least in South America. The general tendency of historical writers has been to feature the table-land agriculture, instead of considering it as a specialized development of the more primitive systems that are still employed in the lower valleys of Peru, as in other parts of tropical America.


A STRIPED VARIETY OF ANYUS
Figure 14
The tubers are thickened and the stripes are purple.

Agricultural Arts of Peru

In addition to the domestication of plants and animals, several agricultural arts were highly developed by the ancient Peruvians. The ancient remains found in the Peruvian region, the accounts written by the early Spanish historians, and the evidence afforded by the Quichua language, leave no doubt that knowledge of the behavior and requirements of the plants, and skill in the agricultural arts, were carried to a more advanced state in Peru than in any other part of America. With regard to some features it is doubtful whether a higher development of agriculture has been attained in any other part of the world. Only a few regions present so wide a range of conditions, nor have such unfavorable natural conditions been utilized in other countries to any such extent as in Peru.

Building of Terraces and Irrigation Works

The nature and extent of the agricultural works of the ancient Peruvians have not been understood or appreciated. The narrow terraces of the steeper slopes have been described by many writers, while the broader terraces on the floors of the valleys have been overlooked. Many square miles of the valley floors have been terraced and the work is so extensive that its artificial character is difficult to credit even in the presence of the facts. Travellers have supposed that the retaining walls were merely stone fences although the fields are on different levels. Many of the retaining walls are of the primitive megalithic type and are marvels of persistent well-organized labor. Stones of great size, weighing many tons, were fitted together with an incredible nicety whose mechanical explanation is still to be found.

Engineering talent was displayed also in the arrangement and grading of the terraces, in straightening and confining the rivers, and in carrying irrigation aqueducts along the precipitous slopes and narrow crests of the mountains, often for many miles. In some districts all of the agricultural lands are of artificial construction and represent an amazing expenditure of labor, second to none of the so-called "Wonders of the World" in the Eastern Hemisphere. The terrace builders were skilful not only in laying up walls, but in the placing of the artificial soil which has retained its fertility after centuries of cultivation. Thus the ancient agriculture of Peru has solved the problem of soil conservation and presented a complete contrast with the wasteful systems that are used at present in many parts of the world.

It is of interest from the standpoint of human evolution that this extreme specialization of the art of agriculture was attained in the prehistoric period, probably many centuries earlier than the Inca empire that Pizzaro conquered. The highest development of the terrace building art was not in the high plateaus, where such terraces were not needed, but in the valleys of the Eastern Andes where the climate was more genial but the soil and the water had to be supplied artificially. From the regular laying-out of the fields it is evident that the eastern valleys were developed as reclamation projects, with the work organized and planned, instead of being done by individual settlers.


A SWEET POTATO IN FLOWER
Figure 15
ROOTS OF THE LLACON
Figure 16
The native name is cusi-cumara, said to mean "long cumara." The same name cumara, is found widely distributed in the Pacific islands, where the sweet potato appears to have been of greater importance as a food crop than in other parts of the world. The bottle gourd was also shared by the Peruvians and the Polynesians before the coming of Europeans, though without such similarity of names. Gourds might conceivably have floated across the Pacific, to take root without the agency of man, but the sweet potato and its name could hardly have been carried in this way. These roots, which resemble the Jerusalem artichoke, are produced by a species of Polymnium [Polymnia sonchifolia], a tall composite herb like a sunflower. The flesh of the root is white and crisp. The Ilacon (or yacon) and the ajipa are two root crops that are eaten raw. All the others require cooking.

 

INCA STOREHOUSES
Figure 17
A line of sixty Inca storehouses at Pinyasniocj near the pass of Panticalla, between the Urubamba and the Lucumayo valleys, at an altitude of about 12,000 feet. The storehouses are built in twenty separate units, with the walls of the sections only a few inches apart. Some of the storehouses have been crushed by huge boulders rolling down the steep slopes. The survival of several kinds of trees in this valley is ascribed to the protection afforded by the boulder-covered hillside.

Terrace agriculture is not only a means of utilizing steep or broken land, otherwise not capable of cultivation, but is also of interest as representing a permanent system of agriculture, in contrast with our ways of using the soil. The ancient Peruvians were soil-makers, while much of our farming is destructive. By means of terracing, the soil is drained and kept in place so that the fertility is not lost, but may continue to increase as it does in uncultivated lands. The terraced lands of the valleys of the eastern Andes undoubtedly have been cultivated continuously for many centuries and are still very productive. The great antiquity of the terrace system thus has a special significance as showing the possibility of a permanent agriculture, which is the necessary basis of a permanent civilization.

Weaving of Cotton and Wool

The textile art also contributed to the occupation of the high valleys and table-lands, and was developed more highly in Peru than elsewhere it America. Cotton was grown in the lower valleys, and used extensively while in the table-lands three kinds of wool were spun and woven, coarse wool from the llama and fine wool from the alpaca, while the material for the very finest work was from the fleeces of the wild vicunas, which were driven together and plucked periodically. Many ancient masterpieces of weaving have been found in the graves of the coast region, including elaborate pictorial tapestry which might be compared in execution, design, and conventionalized symbolism, with the complicated hieroglyphic figures of the ancient Mayas of Central America. Notable artistic ability was also manifested in pottery, poetry and music.

PERUVIAN POTATO VARIETIES
Figure 18
These are from the region of Cuzco and Ollantaytambo. The colors and textures of the tubers are as varied as the shapes and sizes. Some varieties are deep purple under the skin and others purple throughout. The, natives of the table-land districts plant man varieties together, but know the names and qualities of the different kinds as we do the numerous kinds of apples.

Astronomical Determination of Seasons

The natural conditions of the development of agriculture in Peru also tended strongly to encourage observation of the seasonal changes in the position of the sun. The ancient remains show that crowded populations lived in narrow valleys and canyons where the chance of growing crops on the steep slopes was acutely dependent on exposure to the sun. This was especially important at the higher altitudes where the seasons are short and precarious. Each center of population appears to have had its intihuatana or sunpost, for direct observation on the shadow of the sun to determine the advance of the season. Stone pillars were set up to mark the elongation of the shadow the name intihuatana  meaning literally the sun's hitching post. The power to hold the sun, to bring it back from the solstice and to control the weather, was ascribed to the Inca, and was the basis of his sacred authority, much as in China where the emperor was considered responsible for good and bad seasons.

Social Organization and Colonization

The ancient inhabitants of Peru extended the practice of agriculture and the attendant arts over a very wide area by means of a superior system of social organization, quite unparalleled in other parts of America, which made it possible to plan and construct extensive systems of terracing and irrigation, and to send out regularly recruited, well-organized colonies to populate new districts. Thus the Inca Empire at the time of the discovery and conquest was by far the most extensive and populous of the native American states.

Public storehouses were a feature of the Inca polity, that made a very favorable impression upon the early Spanish historians, but were not maintained after the conquest. The storehouses served to increase production by making it possible to cultivate the higher valleys where in some years the crops were destroyed by untimely frosts. But with the storehouses to protect the people from, famine, sufficient food could be grown in the favorable seasons. Corn enough for five years is said to have been stored in some districts. Thus in the old days people lived in many of the higher valleys that are now entirely deserted.

The storehouses were substantial structures, with walls of masonry, many of which are still standing and might be used if the roofs were replaced. Many of the buildings that have been described as fortifications or nunneries, because of their inaccessible locations, are more likely to have been storehouses, as the long high building shown in Figure 9, perched on the crag above the landslide, overlooking the valley of Ollantaytambo. The cool, dry places probably were chosen to keep the stored products in better condition. The storehouses shown in Figure 17 were in a high pass between two important valleys.

Far beyond the range of political power of the Incas, language and other traces of Inca influence have been found in many parts of eastern and northern South America, and possibly extending through the West Indies to Central America and Mexico. The general similarity and wide distribution of the native languages of the Brazilian and even the West Indian region are further evidences of extensive movement of agricultural populations, sometimes, no doubt, replacing and sometimes fusing with more primitive inhabitants.

The natural movements of progress are from centers of population and civilization to less occupied regions. Natural products are carried in and the products and arts of civilization are carried out, sometimes for great distances. For centuries yet uncounted the Peruvian region was the chief center of intensive agriculture and crowded population, and it is reasonable to seek in that quarter the origins of the plants that were widely distributed and formed the general basis of agriculture in other parts of America.

Summary

Domestication should be studied as a biological problem, laying aside the traditional assumption of a primitive pastoral state. Plants probably were domesticated before animals, and this is definitely indicated in America. The primitive civilizations of America were an indigenous development, since they were based on native American plants. A general unity of the native agriculture of America may be recognized, in view of the wide dissemination of the maize plant, usually accompanied by beans, squashes and several attendant species.

The Peruvian region was the chief center of domestication in America, as shown by the large number of plants that were cultivated, estimated at seventy species, and several species of animals.

A study of the native names of cultivated plants in Peru indicates that all of the principal lowland crop plants of other regions were known to the ancient Peruvians before the Spanish conquest. Wild prototypes of these plants have not been discovered in other parts of America and may be sought in the Peruvian region.