A THEORY OF ANGIOSPERM EVOLUTION - Axelrod - - Evolution - Wiley Online LibraryCore angiosperms. The flowering plants , also known as angiosperms , Angiospermae   or Magnoliophyta ,  are the most diverse group of land plants , with 64 orders , families , approximately 13, known genera and , known species. However, they are distinguished from gymnosperms by characteristics including flowers , endosperm within the seeds , and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure; in other words, a fruiting plant. The term comes from the Greek words angeion "case" or "casing" and sperma "seed". They diversified extensively during the Early Cretaceous , became widespread by mya, and replaced conifers as the dominant trees from to 60 mya.
The ancestral flower of angiosperms and its early diversification
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Growing evidence of morphological diversity in angiosperm flowers, seeds and pollen from the mid Cretaceous and the presence of derived lineages from increasingly older geological deposits both imply that the timing of early angiosperm cladogenesis is older than fossil-based estimates have indicated. An alternative to fossils for calibrating the phylogeny comes from divergence in DNA sequence data. Here, angiosperm divergence times are estimated using non-parametric rate smoothing and a three-gene dataset covering ca. The results provide an initial hypothesis of angiosperm diversification times. Using an internal calibration point, an independent evaluation of angiosperm and eudicot origins is performed. The origin of the crown group of extant angiosperms is indicated to be Early to Middle Jurassic Myr , and the origin of eudicots is resolved as Late Jurassic to mid Cretaceous Myr.
The angiosperm carpel is one of the defining characteristics of flowering plants. Carpels are unique to angiosperms and are found in all of its members.
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