''Eleocharis equisetoides'', with common names including horsetail spike-rush, jointed spike-rush, spikesedge, and knotted spike-rush, is a plant species native to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

and

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

, usually in freshwater wetland areas. It is known primarily from the Atlantic coastal plain from

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...

, and the Great Lakes region, with scattered populations elsewhere.Flora of North America v 23 p 120
/ref> ''Eleocharis equisetoides'' and the related ''E. interstincta'' have hollow stems with complete transverse septa. This gives them a jointed appearance superficially resembling the stems of some species of ''

Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns, which reproduce by spores rather than seeds. ''Equisetum'' is a " living fossil", the only living genus of the entire subclass ...

''. The two species can be distinguished by the length of the

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ca ...

bristles A bristle is a stiff hair or feather (natural or artificial), either on an animal, such as a pig, a plant, or on a tool such as a brush or broom. Synthetic types Synthetic materials such as nylon are also used to make bristles in items such as ...

subtending the

achenes An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not op ...

.Elliott, Stephen. Sketch of the Botany of South-Carolina and Georgia 1(1): 79. 1816.

References

equisetoides Flora of the United States Flora of Ontario Plants described in 1816 Flora without expected TNC conservation status {{Cyperaceae-stub