Annularia
Form taxon of extinct plants in the family Calamitaceae
title: "Annularia" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["horsetails", "carboniferous-plants", "prehistoric-plant-genera", "carboniferous-first-appearances", "carboniferous-extinctions", "fossil-taxa-described-in-1821", "fossils-of-georgia-(u.s.-state)", "paleozoic-life-of-new-brunswick", "paleozoic-life-of-nova-scotia", "prehistoric-plants-of-north-america"] description: "Form taxon of extinct plants in the family Calamitaceae" topic_path: "general/horsetails" source: "https://en.wikipedia.org/wiki/Annularia" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Form taxon of extinct plants in the family Calamitaceae ::
| fossil_range = | image = Annularia Stellata.jpg | image_caption = Annularia stellata | taxon = Annularia | authority = Sternberg (1821)
Annularia is a form taxon, applied to fossil foliage belonging to extinct plants of the genus Calamites in the order Equisetales.
Description
Annularia is a form taxon name given to leaves of Calamites. In that species, the leaves formed radiating leaf whorls at each stem node, in a similar way to the branches of Equisetum, an extant genus of horsetails. Annularia leaves are arranged in whorls of between 8 and 13 leaves. The leaf shape is quite variable, being oval in Annularia sphenophylloides and linear to lanceolate in Annularia radiata, but they are always flat and of varying lengths.
Calamites were arborescent and grew to a height of 32 ft.
Fossil records
Fossils of this genus have been discovered in the Permian strata of Russia and in the Carboniferous (around ) strata of the United States, Canada, China and Europe.
Calamitaceae - Annularia stellata.JPG|Specimen of Annularia stellata from Italy on display at the Museo Civico di Storia Naturale di Milano Calamitaceae foliage.jpg|The foliage of Calamites Calamites reconstrucción.png|Calamites reconstruction
References
References
- [https://web.archive.org/web/20071222010031/http://es.encarta.msn.com/encyclopedia_961537580/Annularia.html MSN]
- [http://www.museum.state.il.us/exhibits/mazon_creek/annularia.html Illinois State Museum - Annularia sp. Mazon Creek Fossils]
- [https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=271024 Paleobiology Database]
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