Equisetum

Scientific name

Equisetum L.

Common names

scouring rush, horsetail

Family

Equisetaceae

Similar genera

Eleocharis

Native distribution

temperatetemperate:
(adj) of the climatic zone between boreal and tropical
Northern Hemisphere

Species cultivated

Equisetum fluviatile L.

E. hyemale L.

E. scirpoides Michx.

Adventive distribution

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

Weed status

While some terrestrialterrestrial:
(adj) growing on land as opposed to living in water
species of Equisetum are recorded as weedy, the weed potential of aquatic Equisetum spp. is not well known.

Habit

emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
, rhizomatousrhizomatous:
(adj) possessing rhizomes
, spore-bearing

Brief description

Perennial. Underground rhizomerhizome:
(n) an underground stem, usually growing horizontally, from which both roots and shoots emerge directly; the thick, above-ground stem of ferns
giving rise to erect stems. Stems grooved and jointed, simple or with whorledwhorled:
(n) bearing whorls; a type of leaf arrangement (phyllotaxis) in which leaves are in whorls
branches. Leaves reduced to small, whorledwhorled:
(n) bearing whorls; a type of leaf arrangement (phyllotaxis) in which leaves are in whorls
, fused scales at joints. Cone at stem apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
or borne on special, sterilesterile:
(adj) lacking male and/or female reproductive parts; not producing fruit, seed, pollen, spores, etc.
shoots, consisting of numerous sporangiophores, from which spores are produced. Dispersal by spores and rhizomerhizome:
(n) an underground stem, usually growing horizontally, from which both roots and shoots emerge directly; the thick, above-ground stem of ferns
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 between 15 and 35 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.