In enumerating the species of the genus _Cucurbita_, I should explain that their distinction, formerly exceedingly difficult, has been established by M. Naudin[1251] in a very scientific manner, by means of an assiduous cultivation of varieties and of experiments upon their crossed fertilization. Those groups of forms which cannot fertilize each other, or of which the product is not fertile and stable, are regarded by him as species, and the forms which can be crossed and yield a fertile and varied product, as races, breeds, or varieties. Later experiments[1252] showed him that the establishment of species on this basis is not without exceptions, but in the genus _Cucurbita_ physiological facts agree with exterior differences. M. Naudin has established the true distinctive characters of _C. maxima_ and _C. Pepo_. The leaves of the first have rounded lobes, the peduncles are smooth and the lobes of the corolla are curved outwards; the second has leaves with pointed lobes, the peduncles marked with ridges and furrows, the corolla narrowed towards the base and with lobes nearly always upright. The principal varieties of _Cucurbita maxima_ are the great yellow gourd, which sometimes attains to an enormous size,[1253] the Spanish gourd, the turban gourd, etc. Since common names and those in ancient authors do not agree with botanical definitions, we must mistrust the assertions formerly put forth on the origin and early cultivation of such and such a gourd at a given epoch in a given country. For this reason, when I considered the subject in 1855, the home of these plants seemed to me either unknown or very doubtful. At the present day it is more easy to investigate the question. According to Sir Joseph Hooker,[1254] _Cucurbita maxima_ was found by Barter on the banks of the Niger in Guinea, apparently indigenous, and by Welwitsch in Angola without any assertion of its wild character. In works on Abyssinia, Egypt, or other African countries in which the species is commonly cultivated, I find no indication that it is found wild. The Abyssinians used the word _dubba_, which is applied in Arabic to gourds in general.