Field Horsetail, Equisetum arvense
Field horsetail, Equisetum arvense, is found in throught out the Northern Hemisphere. There are populations in New Zealand and Australia.
The genus Equisetum is a 'living fossil' genus.
iNaturalist map of E. avernse
E. avernse is a member of the genus Equisteum, of which there is only one genus, and a member of the only family Equisetaceae. The specie has a fertile and sterile form.
The structures of Equisetum are radically different for 'true ferns'. It has its own morphology and nomenclature.
The sterile form has a green central stalk with green whorl shaped leaves at each node.
Domestic, Fairfield, CT, USA
The fertile form is a single stalk, with no chlorophyll. The spores are contained in a structure called a strobilis at the top of the stalk. The fertile stalks appear in spring and last only a few weeks.
Bartholomew's Cobble, Sheffield, MA, USA
Cultivated, Fairfield, CT, USA May 2025
Close up of the node where the whorls emerge. The tiny teeth leaves are up against the stem. The number of whorls at a node is one character used to identify species of Equisetum species.