'subclass Hamamelidae' definitions:

noun

A group of chiefly woody plants considered among the most primitive of angiosperms; perianth poorly developed or lacking; flowers often unisexual and often in catkins and often wind pollinated; contains 23 families including the Betulaceae and Fagaceae (includes the Amentiferae); sometimes classified as a superorder [syn: Hamamelidae, subclass Hamamelidae]