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The term "gymnosperm" is often used in paleobotany to refer to (the paraphyletic group of) all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used. [5] The gymnosperms and angiosperms together constitute the spermatophytes or seed plants.
The gymnosperms consist of five orders of seed plants: Cupressales, Cycadales, Ginkgoales, Gnetales and Pinales. [a] They developed more than 350 million years ago, long before flowering plants, according to the fossil record. The name comes from the Greek for "naked seed"; the egg cells are not protected by ovaries, as in flowering plants. [4]
However, angiosperms appear suddenly and in great diversity in the fossil record in the Early Cretaceous (~130 mya). [48] [49] Claimed records of flowering plants prior to this are not widely accepted. [50] Molecular evidence suggests that the ancestors of angiosperms diverged from the gymnosperms during the late Devonian, about 365 million ...
Gnetophyta (/ n ɛ ˈ t ɒ f ɪ t ə, ˈ n ɛ t oʊ f aɪ t ə /) is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: Gnetum (family Gnetaceae), Welwitschia (family Welwitschiaceae), and Ephedra (family ...
The spermatophytes were traditionally divided into angiosperms, or flowering plants, and gymnosperms, which includes the gnetophytes, cycads, [5] ginkgo, and conifers. Older morphological studies believed in a close relationship between the gnetophytes and the angiosperms, [6] in particular based on vessel elements.
1 Gymnosperms. 2 Angiosperms. 3 See also. 4 References. ... The examples and perspective in this article may not represent a worldwide view of the subject.
A current example of how this might have happened can be seen in the precocious spore germination in Selaginella, the spike-moss. The result for the ancestors of angiosperms and gymnosperms was enclosing the female gamete in a case, the seed. The first seed-bearing plants were gymnosperms, like the ginkgo, and conifers (such as pines and firs ...
Flower of Liriodendron tulipifera, a Mesangiosperm. Mesangiospermae is a clade that contains the majority of flowering plants (angiosperms). Mesangiosperms are therefore known as the core angiosperms, in contrast to the three orders of earlier-diverging species known as the basal angiosperms: Nymphaeales (including water lilies), Austrobaileyales (including star anise), and Amborellales.