A subdivision of large-leaved gymnosperms with stout stems in the plant division Pinophyta; only a few species are extant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
(also Cycadophytina), a subphylum of gymno-spermous plants that includes three classes: Lyginopteridopsida, Cycadopsida, and Bennettitales.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.