Chemical constituents and systematics of Amentiferae

The systematic value of various kinds of chemical constituents reported from Amentiferae is discussed in terms of chemical structural complexity and restricted distribution. Chemical evidence suggests the cohesiveness of Urticales, excluding Eucommiaceae. It also suggests that Garryaceae, Platanaceae, and Myricaceae are distinct from other families of Amentiferae. The absence of reports of elaborate, restricted naturalproduct structural types in Betulaceae, Fagaceae, Casuarinaceae, Juglandaceae, and Salicaceae means that there is no positive chemical evidence suggesting relatedness of these core families of Amentiferae.