| Noun | 1. | subdivision Gnetophytina - gymnospermous flowering plants; supposed link between conifers and angiosperms; in some systems classified as a class (Gnetopsida) and in others as a subdivision (Gnetophytina or Gnetophyta) class - (biology) a taxonomic group containing one or more orders class Gymnospermae, division Gymnospermophyta, Gymnospermae, Gymnospermophyta - plants having naked seeds not enclosed in an ovary; in some systems considered a class (Gymnospermae) and in others a division (Gymnospermophyta); comprises three subdivisions (or classes): Cycadophytina (class Cycadopsida) and Gnetophytina (class Gnetopsida) and Coniferophytina (class Coniferopsida); in some classifications the Coniferophytina are divided into three groups: Pinophytina (class Pinopsida) and Ginkgophytina (class Ginkgopsida) and Taxophytina (class Taxopsida) Gnetales, order Gnetales - chiefly tropical or xerophytic woody plants; practically unknown as fossils but considered close to the ancestral line of angiosperms |