by clear and decisive characters. The species of Iris form also a numerous genus, and the Willows another; while the curious Epimedium alpinum, Engl. Bot. t. 438, is too singular and distinct to be associated with any plant besides, and constitutes a genus by itself, as well as the Adoxa, t. 453, and Linnæa, t. 433.
The first great and successful attempt to define the genera of plants was made by Tournefort, and in this his transcendent merit will ever be conspicuous, though his system of arrangement should be entirely forgotten. Not that he has excelled in verbal definitions, nor built all his genera on sure foundations; but his figures, and his enumerations of species under each genus, show the clearness of his conceptions, and rank him as the father of this branch of botany.
Linnæus first insisted on generic characters being exclusively taken from the 7 parts of fructification, and he demonstrated these to be sufficient for all the plants that can be discovered. He also laid it down as a maxim, that all genera are as much founded in nature as the species which compose them; and
