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Diagram of an ovule in gymnosperms and angiosperms Photomicrograph of an ovule of a monocotyledon. In angiosperms the gynoecium, also called pistil, consists of one or more carpels or carpel leaves that form a cavity, the ovary, inside which the ovules or seminal primordia are protected from both desiccation and attack by phytophagous insects.
The gymnosperms (/ ˈ dʒ ɪ m n ə ˌ s p ɜːr m z,-n oʊ-/ ⓘ nə-spurmz, -noh-; lit. ' revealed seeds ') are a group of woody, perennial seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae [2] The term gymnosperm comes from the ...
The fossil history of flowering plants records the development of flowers and other distinctive structures of the angiosperms, now the dominant group of plants on land.The history is controversial as flowering plants appear in great diversity in the Cretaceous, with scanty and debatable records before that, creating a puzzle for evolutionary biologists that Charles Darwin named an "abominable ...
Resin ducts are common in gymnosperms and occur in various tissues of roots, stems, leaves, and reproductive structures. Gum ducts are similar to resin ducts and may contain resins, oils, and gums. Usually, the term gum duct is used with reference to the dicotyledons, although gum ducts also may occur in the gymnosperms. Oil ducts are ...
The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the spermatophytes, ancestral to both gymnosperms and angiosperms (flowering plants). [1]
The Cretaceous Terrestrial Revolution (abbreviated KTR), also known as the Angiosperm Terrestrial Revolution (ATR) by authors who consider it to have lasted into the Palaeogene, [1] describes the intense floral diversification of flowering plants (angiosperms) and the coevolution of pollinating insects, as well as the subsequent faunal radiation of frugivorous, nectarivorous and insectivorous ...
Initially higher plants (Embryophyta or terrestrial plants) were considered in two divisions, Embryophyta Asiphonogama (bryophytes, pteridophytes) and Embryophyta Siphonogama (Spermatophytes: gymnosperms, angiosperms), but were later subdivided.
Detailed morphological and molecular studies have shown that the group is not actually monophyletic, [2] with proposed floral homologies of the gnetophytes and the angiosperms having evolved in parallel. [3] This makes it easier to reconcile molecular clock data that suggests that the angiosperms diverged from the gymnosperms around 320-300 mya ...