All species of Cucurbita (which includes squashes, pumpkins, and the common, small, yellow-flowered gourds) are native to the Americas. Their center of origin lies in Mexico where most of the 26 wild and cultivated species still grow. Chilicayote (C. ficifolia), a perennial and probably the oldest cultivated species, is grown from Mexico to Bolivia and known archaeologically only from coastal Peru (3000 B.C.). Oldest archaeological cucurbits are C. pepo and Lagenaria siceraria, the bottle gourd. Specimens of these species were recovered from Tamaulipas in cave material dated 7000-5500 B.C. Pepo and Lagenaria spread over most of the United States probably with the advent of agriculture. Cucurbita moschata appeared in coastal Peru at the same time as C. ficifolia (3000 B.C.), but it does not occur in the Ocampo Cave cultures until 1400-400 B.C. when pottery and village life entered, and corn, cotton, pepo, and beans (common, lima and jack) were being grown. While the earliest dates for moschata in southwestern United States are about A.D. 1100, it probably entered the same time as cotton, perhaps as early as A.D. 700. Cucurbita mixta, the cushaw, is the most recent of the cultivated species. It is found mainly in Mexico and in post-A.D. 1000 sites in the southwestern U.S. Prehistoric C. maxima is known only from Peru and to the south and east in Chile and Bolivia. Its ancestors probably were carried there by man from the Mexican center, and the weedy C. andreana may have been taken along at the same time.
The bottle gourd is most variable in the Old World. It probably originated there, and was carried to the New World in pre-agricultural times by ocean currents. A number of other cucurbits and the tree gourd, Crescentia cujete, not a true gourd but a member of the family Big-noniaceae, are briefly mentioned. Parts useful in identifying the cultivated cucurbits are the fruit stem or peduncle, seeds, rind, and leaves. A list of the collections of Cucurbita and Lagenaria which have been studied is given, with estimates for the date of each site.