VI. In none of the preceding cases has hybridism, no matter in what degree, given rise to a series of individuals descended the one from the other; and preserving the same characters. An exception is, however, known to this general fact. It is unique, and is produced in the vegetable kingdom from the crossing of wheat with _Ægilops ovata_. The hybrid of the first generation from these two species is sometimes produced naturally, and was regarded by Requien as a species. Fabre, who frequently met with it in the fields, considered it to be the commencement of the transmutation of the Ægilops into wheat. Afterwards a quadroon hybrid, accidentally obtained and cultivated during several years, gave him descendants resembling the _beardless wheat_ of the South. It was the result of _reversion_. Fabre, however, who did not recognise the hybrid, thought it was a transmutation, and flattered himself that he had discovered wild wheat in the Ægilops. M. Godron, on the contrary, understood the nature of the phenomenon, and demonstrated it experimentally. He crossed the Ægilops and the wheat, and obtained the first plant of Requien, the _Ægilops triticoïdes_ of Fabre. He again crossed this hybrid with the true wheat, and reproduced the pretended artificial wheat of the Montpellier botanist. He gave to it the name of _Ægilops speltæformis_. It is this latter form, having as we see three-fourths of the true wheat, and a fourth of the Ægilops, that M. Godron has cultivated at Nancy since 1857. The clever naturalist who has produced it, believes that he has not had one case of reversion like those at Montpellier and those of Fabre. But at the same time he informs us that the most minute and special precautions alone can preserve this artificial plant. The ground must be prepared with the greatest care, and each seed placed by hand in the desired position. If put into the ground carelessly, or scattered over the bed, the seeds never germinate. M. Godron considered that the Ægilops speltæformis would entirely disappear, perhaps in a single year, if left to itself. VII. Finally, the characters of hybrids are: infertility, as a general rule, and, in the exceptions, a very limited fertility; series suddenly cut short either by infertility, by disordered variation, or by reversion without atavism. The Ægilops triticoïdes alone seems to stand in opposition to all other known facts. This exception is undoubtedly remarkable, but does not in any way impair our general conclusions. A product of human industry, this hybrid plant only exists by virtue of the same industry, and cannot, from any point of view, be compared to the succession of mongrel individuals which are unceasingly propagated without our aid, and in spite of our precautions, in the midst of our animal and vegetable races.