Equisetum

Scientific name

Equisetum L.

Common names

scouring rush, horsetail

Family

Equisetaceae

Could be confused with

Eleocharis

Native distribution

temperate Northern Hemisphere

Species commonly cultivated

Equisetum fluviatile L. (Europe, North America)

E. hyemale L. (North America)

E. scirpoides Michx. (Eurasia, Greenland, North America)

Adventive distribution

Three species are introduced into Australia, and E. hyemale is introduced into New Zealand.

Weed status

While some terrestrial species of Equisetum are recorded as weedy, the weed potential of aquatic Equisetum spp. is not known. All species of Equisetum are prohibited in Australia.

Habit

emergent, rhizomatous, spore-bearing

Brief description

Perennial. Underground rhizome giving rise to erect stems. Stems grooved and jointed, simple or with whorled branches. Leaves reduced to small, whorled, fused scales at joints. Cone at stem apex or borne on special, sterile shoots, consisting of numerous sporangiophores, from which spores are produced. Dispersal by spores and rhizome fragments.

Natural habitat

wet ground, rarely in shallow water

Additional comments

Equisetum is an ancient genus, the only remaining representative of the division Equisetophyta (one of the divisions of non seed-bearing vascular plants). Equisetum has about 25 species in two subgenera, with only two aquatic species. In the subgenus Equisetum (horsetails) the stems are soft and tend to be regularly branched, whereas the stems of the subgenus Hippochaete (scouring rushes) tend to be hard, fibrous, and unbranched or irregularly branched.