The Spermatophyta fall into two classes, Gymncsperms (q.v.) and Angiosperms; the former are the more primitive group, appearing earlier in geological time and showing more resemblance in the course of their life-history to the Pteridophyta.
The Spermatophyta are thus land plants par excellence and have, with the few exceptions cited, lost all trace of an aquatic ancestry.
A system of classification for the Phanerogams, or, as they are frequently now called, Spermatophyta (seed-plants), which has been much used in Great Britain and in America, is that of Bentham and Hooker, whose Genera Plantarum (1862-1883) is a descriptive account of all the genera of flowering plants, based on their careful examination.
In modern botanical works the group is often known as the seed-plants (Spermatophyta).