Gymnospermer

Gymnosperms are a group of seed-producing vascular plants that includes conifers, cycads, Ginkgo, and gnetophytes. Their seeds are exposed on the surfaces of reproductive structures rather than enclosed within a fruit, which distinguishes them from angiosperms. Gymnosperms are among the oldest living seed plants, with fossil records extending back to the late Paleozoic era.

In gymnosperms, the sporophyte is the dominant generation. Male cones produce pollen in microsporangia, while female cones house ovules in megasporangia. Pollen is typically transported by wind and, after fertilization, seeds develop on the cone scales. The embryo is nourished by tissues derived from the female gametophyte, a nutritive tissue that remains within the seed as it develops.

The major groups are conifers (such as pines, spruces, firs, and cedars), cycads, Ginkgo, and gnetophytes (including Welwitschia, Ephedra, and Gnetum). They inhabit a wide range of environments, from boreal forests and temperate regions to tropical and desert areas.

Ecology and evolution: Gymnosperms were more diverse in the Paleozoic and early Mesozoic, but today they persist as important components of many ecosystems, particularly in cooler or drier climates. They tend to be long-lived and slow-growing, with some species forming extensive forests or distinctive shrublands. Economically, gymnosperms provide timber, resins, and ornamental material and play roles in ecosystems as windbreaks and habitat for wildlife.