Horsetails are fern-like in function but not fern-like in shape, and they are consumed by all kind of wildlife, including mammals. Horsetail stems stand erect, 2-5 ft. tall, ridged, and dark evergreen, with jointed nodes and conspicuous blackish rings around the nodes. They are hollow between nodes and the leaves are reduced to very small node-scales. The cone-like structure at stem tip is called a "strobilus", and are various shades of brown. They grow to 1 in. long and contain sporangia which produce green reproductive spores. They are found along stream sides, often in sandy, alluvial soils, and while widespread , they are not too common.

Silica is deposited in and on the wall of epidermal cells and this imparts a rough texture to the plants, and because these rough, silica-containing stalks were used in frontier times to scour pots and pans, the common name for some species became "Scouring Rush."