Terrestrial or aquatic plants. Stems long-creeping below ground, above ground they are hollow and grooved, divided into distinct units by joints (nodes). Branches arranged in whorls. Leaves many, reduced and tooth-like in regular whorls at the nodes and united into a sheath at the base. Sporangia in stalked organs (sporangiophores) that are clustered into a terminal cone-like structure.
Horsetails are a group of fern allies with distinctive tail-like jointed stems (hence the common name). They have little horticultural potential and the rootstock, which is a creeping rhizome, may be invasive and weedy.
The horsetails are the living representatives of similar much larger plants that thrived in the Carboniferous period about 350 million years ago together with the lycopods and true ferns; they form a very distinct group with no close relatives.
A family consisting of a single genus, Equisetum.
Uses: The siliceous stems were once used as abrasives for polishing. In horticulture they are generally used as ornamental waterside plants.
Recognition: Hollow, tail-like jointed stems with small, simple leaves arranged in sheathing whorls.
Source: (1995). Equisetaceae. In: . Horticultural Flora of South-eastern Australia. Volume 1, Ferns, conifers & their allies. The identification of garden and cultivated plants. University of New South Wales Press.
Updated by: Roger Spencer, April 2018