Fossils of Mesozoic fern leaves, called morphospecies or artificial species. They have pinnae similar to those of certain species of the Osmundae family, but are composed of bare leaves that do not produce asci. Fossils of this genus include various species whose relative relationships are unclear in fossil botany. However, since some species are useful for stratigraphy, they are the subject of research by geologists. They are also found in Japan, where more than a dozen species have been described from the Triassic to the Cretaceous periods. Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information |
中生代のシダ類の葉の化石で,形態種または人為的種といわれるもの。ゼンマイ科のある種に似た羽片をもつが,子嚢を生じていない裸葉から成る。この属名で呼ばれる化石は,化石植物学上,類縁関係の不明ないろいろのものが含まれている。しかし,層位学的に役立つものが含まれているので,地質学者の研究対象とされており,日本にも産出があり,三畳紀から白亜紀にかけて十数種が記載されている。
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