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Name: Annularia stellata
Division: Equisetophyta; Class: Equisetopsida; Order: Equisetales; Family: Calamitaceae; Genus: Annularia (extinct)
Age: Carboniferous Duckmantian Stage (330 million years old)
Size (25.4 mm = 1 inch): 130 mm tall by 55 mm wide on a 180 mm by 83 mm matrix
Location: Western Arkansas, United States
| Description: This fine specimen shows two leaflets of Calamites, a member of the Calamitales which belong to the Sphenophytes. Whorls of small leaflets are arranged concentrically around a thin stem and are called Annularia or Asterophyllites. Calamites itself is the name originally given to a stem section (see my other offerings), but now applies to the entire plant. These were indicative of humid to wet habitats such as along rivers and lake shores. This one is quite affordable for such a fine large example of multiple whorls that comes from the coal-producing regions of France. The only living example of the sphenophytes is the horsetail Equisetum. The reverse shows several other plant fragments, making for a fine representation of the ancient Carboniferous forests of the region. |
