horsetail

A primitive, spore-bearing perennial related to ferns and clubmosses; creeping rhizomes; annual, distinctively jointed stem; whorl of scale-like leaves around each joint; cone-like strobilus at the tip. It is found everywhere, except for Australasia, and the only living genus of a large and formerly widespread group, the Sphenopsida, dominant during the Carboniferous period. All extant species are herbaceous, but many fossil species were arborescent. (Genus: Equisetum, 23 species. Family: Equisetaceae.)

iHorsetail
Vegetative stem of Equisetum telmateia with a whorl (at each node) of branches and dark-tipped leaves
Scientific classification
Kingdom: Plantae Division: Equisetophyta Class: Equisetopsida Order: Equisetales Family: Equisetaceae Genus: Equisetum
Species
See text

The horsetails are vascular plants, comprising 15 species of plants in the genus Equisetum.

The name horsetail arose because it was thought that the stalk resembled a horse's tail, the name Equisetum being from the Latin equus, "horse", and seta, "bristle". They are perennial plants, either herbaceous, dying back in winter (most temperate species) or evergreen (some tropical species, and the temperate species Equisetum hyemale, E.

Species

Subgenus Equisetum Equisetum arvense - Field or Common Horsetail Equisetum bogotense - Andean Horsetail Equisetum diffusum - Himalayan Horsetail Equisetum fluviatile - Water Horsetail Equisetum palustre - Marsh Horsetail Equisetum pratense - Shade or Meadow Horsetail Equisetum sylvaticum - Wood Horsetail Equisetum telmateia - Great Horsetail Subgenus Hippochaete Equisetum giganteum - Giant Horsetail Equisetum myriochaetum - Mexican Giant Horsetail Equisetum hyemale - Rough Horsetail Equisetum laevigatum - Smooth Horsetail Equisetum ramosissimum - Branched Horsetail Equisetum scirpoides - Dwarf Horsetail Equisetum variegatum - Variegated Horsetail

Named hybrids

Hybrids between species in subgenus Equisetum Equisetum × litorale Kühlew ex Rupr. = Equisetum fluviatile × Equisetum arvense Equisetum × dycei C.N.Page = Equisetum fluviatile × Equisetum palustre Equisetum × willmotii C.N.Page = Equisetum fluviatile × Equisetum telmateia Equisetum × rothmaleri C.N.Page = Equisetum arvense × Equisetum palustre Equisetum × robertsii Dines = Equisetum arvense × Equisetum telmateia Equisetum × mildeanum Rothm. = Equisetum pratense × Equisetum sylvaticum Equisetum × bowmanii C.N.Page = Equisetum sylvaticum × Equisetum telmateia Equisetum × font–queri Rothm. = Equisetum palustre × Equisetum telmateia Hybrids between species in subgenus Hippochaete Equisetum × moorei Newman = Equisetum hyemale × Equisetum ramosissimum Equisetum × trachydon A.Braun = Equisetum hyemale × Equisetum variegatum Equisetum × schaffneri Milde = Equisetum giganteum × Equisetum myriochaetum Equisetum × ferrissii Clute = Equisetum hyemale × Equisetum laevigatum Equisetum × nelsonii (A.A.Eat.) Schaffn. = Equisetum laevigatum × Equisetum variegatum

The superficially similar flowering plant, Mare's tail (Hippuris vulgaris), unrelated to the genus Equisetum, is occasionally misidentified and misnamed as a horsetail. UK National Collection - includes a taxonomic list of all known species and hybrids The Wonderful World of Equisetum Giant horsetails Wikimedia Commons has media related to: Category:Equisetaceae