Any plant whose ovules and the seeds into which they develop are borne unprotected, rather than enclosed in ovaries, as are those of the flowering plants (the term gymnosperm means naked seed). In traditional systems of classification such plants were classified as the Gymnospermae, a class of the Spermatophyta, but they are now divided into separate phyla: Coniferophyta (conifers), Cycadophyta (cycads), Ginkgophyta (ginkgo), and Gnetophyta (e.g. Welwitschia). See also progymnosperms.