Plant
Annularia
Horsetail foliage
Annularia is the whorled leaf of the giant horsetail Calamites, preserved in Mazon Creek concretions and Pennsylvanian shales worldwide as rosettes of narrow leaves around a stem. Concretions with Annularia are common and cheap and among the most attractive Mazon Creek plants. Species are separated by leaf shape and number.
| Phylum | Tracheophyta |
|---|---|
| Class | Equisetopsida |
| Order | Equisetales |
| Family | Calamitaceae |
| Group | Plant |
| Rank (PBDB) | genus· Paleobiology Database |
| Author | Sternberg 1821· Paleobiology Database |
| Classification (PBDB) | Pteridophyta › Polypodiopsida › Equisetales › NO_FAMILY_SPECIFIED· Paleobiology Database |
| Range (PBDB) | 330–247 Ma· Paleobiology Database |
| PBDB occurrences | 398· Paleobiology Database |
Photographs
Elsewhere
- GBIF: 2530174
- PBDB: 271024
- Wikidata: Q105134179
- PBDB taxon page
- Wikipedia: Annularia
- PBDB search: Annularia
Cite this article
Stratum Strata. "Annularia" (Taxon). Stratum Strata pack 2026.09, as of 2026-09-21. https://stratum.black/strata/taxa/annularia. Accessed 2026-09-21.
@misc{stratum-annularia,
title = {Annularia},
author = {{Stratum Strata}},
howpublished = {\url{https://stratum.black/strata/taxa/annularia}},
year = {2026},
note = {Taxon article, Stratum Strata pack 2026.09, as of 2026-09-21; sources: stratum, pbdb, wikidata, smithsonian, nhm. Accessed 2026-09-21.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.