Hamamelidae

(botany) A small subclass of plants in the class Magnoliopsida having strongly reduced, often unisexual flowers with poorly developed or no perianth.

A small subclass of the class Magnoliopsida (dicotyledons) in the division Magnoliophyta (Angio-spermae), the flowering plants, consisting of 11 orders (Trochodendrales, Hamamelidales, Daphniphyllales, Didymelales, Eucommiales, Urticales, Leitneriales, Juglandales, Myricales, Fagales, and Casuarinales), 24 families, and about 3400 species. They have strongly reduced,often unisexual flowers with poorly developed or no perianth. With the notable exception of some of the Urticales, they are all woody plants. Pollination is usually by wind. Many of the families formerly grouped under the Amentiferae belong to the Hamamelidae. See articles on each order. See also Magnoliophyta; Magnoliopsida; Plant kingdom.