Among Hungarian novels we may distinguish four dominant genres or tendencies.
Classification of this literature by traditional subdivision into genres is difficult, and, at the best, unprofitable.
In this book attention was also directed to the succession of forms in the various geological periods, with the important result (stated in modern terms) that in the Palaeozoic period the Pteridophyta are found to predominate; in the Mesozoic, the Gymnosperms; in the Cainozoic, the Angiosperms, a result subsequently more fully stated in his "Tableau des genres de vegetaux fossiles" (D'Orbigny, Diet.
His systematic work is represented by a large number of papers and monographs, many of which relate to the flora of New Caledonia; and by his Enumeration des genres de plantes cultivees au Musee d'Histoire Naturelle de Paris (1843), which is an interesting landmark in the history of classification in that it forms the starting-point of the system, modified successively by A.
For this he made a collection of manuscripts, which he sold in 1835 (many of them passed into the library of Sir Thomas Philipps), drawing up a catalogue under the singular title of Traite de materiaux manuscrits de divers genres d'histoire.