Annularia sp.

ISM 15420a
coin = 19mm (~0.75 in.)

Annularia sp. are the leaf whorls of an extinct horsetail.

They would have grown on plants with stems similar to Calamites.

These horsetails (Sphenopsida) were arborescent (tree-like) and grew to a height of 10 meters (32 feet).

top of Mazon Creek Plants section
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