Horsetails are non-flowering plants which produce spores and are generally recognized as fern allies, because they produce no seeds. They are primitive plants that date back about three million years ago.
Rough Horsetails (Equisetum hyemale) have scale-like leaves that clasp the stem. The evergreen stems contain silica and were once used for polishing kitchen ware, accounting for the common name “Scouring rush.”
The Field Horsetail (Equisetum arvense) usually is found in moist, sandy sites but can be found in various other dry sites.
Of the two locations that I have seen within Pittsylvania County these plants had spread by underground stems (rhizomes) into large colonies alongside a sandy creek edge.
(Also see this photograph in larger format; and the University of Maryland Medical Center's information on the medicinal uses of Horsetail.)
Copyright © 2006 William T. Hathaway.