ORIGIN OF DOMESTIC PLANTS. 
73 
modified and improved forms of wild, self-propagating vege¬ 
tation. The narratives of botanical travellers have often 
announced the discovery of the original form and habitat of 
domesticated plants, and scientific journals have described the 
experiments by which the identity of particular wild and cul¬ 
tivated vegetables has been thought to be established. It is 
confidently affirmed that maize and the potato—which we 
must suppose to have been first cultivated at a much later 
period than the breadstuff's and most other esculent vegetables 
of Europe and the East—are found wild and self-propagating 
in Spanish America, though in forms not recognizable by the 
common observer as identical with the familiar corn and tuber 
of modern agriculture. It was lately asserted, upon w T hat 
seemed very strong evidence, that the JEgilops ovata , a plant 
growing wild in Southern France, had been actually converted 
into common wheat; but, upon a repetition of the experi¬ 
ments, later observers have declared that the apparent change 
was only a case of temporary hybridation or fecundation by 
the pollen of true wheat, and that the grass alleged to be trans¬ 
formed into wheat could not be perpetuated as such from its 
own seed. 
The very great modifications which cultivated plants are 
constantly undergoing under our eyes, and the numerous 
varieties and races which spring up among them, certainly 
countenance the doctrine, that every domesticated vegetable, 
however dependent upon human care for growth and propaga¬ 
tion in its present form, may have been really derived, by a 
long succession of changes, from some wild plant not now 
much resembling it. But it is, in every case, a question of 
evidence. The only satisfactory proof that a given wild plant 
is identical with a given garden or field vegetable, is the test 
of experiment, the actual growing of the one from the seed of 
the other, or the conversion of the one into the other by trans¬ 
plantation and change of conditions. It is hardly contended 
that any of the cereals or other plants important as human 
aliment, or as objects of agricultural industry, exist and propa¬ 
gate themselves uncultivated in the same form and with the 
