Annularia

Annularia is a form taxon, applied to fossil foliage belonging to extinct plants of the genus Calamites in the order Equisetales.

Annularia
Temporal range: Carboniferous
Annularia stellata
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Class: Polypodiopsida
Subclass: Equisetidae
Order: Equisetales
Family: †Calamitaceae
Genus: †Annularia
Sternberg (1821)

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 8-13 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.[1]

Calamites were arborescent and grew to a height of 32 feet (10 meters).[2]


Fossil records

Fossils of this genus have been discovered in the Permian strata of Russia and in the Carboniferous (around 360 to 300 million years ago) strata of the United States, Canada, China and Europe.[1][3]

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See also

References
  1. MSN
  2. Illinois State Museum - Annularia sp. Mazon Creek Fossils
  3. Paleobiology Database
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