单词	gymnosperm
释义	gymnosperm /ˈdʒɪmnə(ʊ)spəːm / noun Botany A plant of a group that comprises those that have seeds unprotected by an ovary or fruit, including the conifers, cycads, and ginkgo. Compare with angiosperm. Subdivision Gymnospermae, division Spermatophyta. Taxonomists can now say that the ferns' closest cousins are the seed plants - angiosperms (flowering plants) and gymnosperms (such as conifers).... The known flora consists of 41 ferns and fern allies, 3 gymnosperms, 291 monocots, and 516 dicots. Moreover, since the expression pattern is similar in a gymnosperm and in an angiosperm this function appears to be evolutionarily conserved. Derivatives gymnospermous /dʒɪmnə(ʊ)ˈspəːməs / adjective ... In contrast, the interval between c.916m and 885.9Om is totally dominated by gymnospermous saccate pollen, with very few fern spores. So this is a time period where gymnospermous plants predominated, including cycadioids which look like modern cycads, and various groups of extinct conifers and seed ferns. The late Triassic showed major radiation of plants, gymnospermous groups in particular, in both the Northern and Southern Hemispheres.
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