Equisetum arvense

field horsetail

Equisetaceae

The Basics

USFS Plant Database

Field horsetail is a facultative wetland species. Field horsetail occurs in woods, fields, meadows and swamps, and moist soils alongside streams, rivers, and lakes, and in disturbed areas...Field horsetail is an early colonizer of moist, primary successional sites created by glacial retreat...Field horsetail is present in both seral and climax communities; its presence is largely dictated by edaphic conditions rather than shade or other factors. Field horsetail is an early colonizer on floodplain deposits. These communities are often destroyed by flooding before beingcan stabilized by willow establishment.

Native Americans and early settlers used tea made from field horsetail as a diuretic. Field horsetail was used as a cough medicine for horses. Dyes for clothing, lodges, and porcupine quills were made from field horsetail. It was used for scouring and polishing objects. The young shoots were eaten either cooked or raw.

The accepted scientific name for field horsetail is Equisetum arvense L. Fernald listed E. a. var. boreale (Bong.) Ledeb., a northern variety. There are a number of named forms that are not accepted by most authors as true forms; they may be growth variants that depend on environmental conditions and are not sufficiently distinct to warrant taxonomic recognition.

Field horsetail is abundant in many spruce communities, including white spruce (Picea glauca), black spruce (P. mariana), blue spruce (P. pungens), and Engelmann spruce (P. engelmannii). In Alberta and British Columbia, other common understory species in the white spruce communities in which field horsetail is abundant include prickly rose (Rosa acicularis), honeysuckle (Lonicera involucrata), bunchberry (Cornus canadensis), twinflower (Linnea borealis), naked miterwort (Mitella nuda), and mountain fern moss (Hylocomium splendens). (Plant Database)

Identification

Field horsetail is a native, perennial, rhizomatous cryptogam. The sporophyte is dimorphic with unbranched, fertile (stroboliferous), spore-producing stems and branched, sterile stems. The spores germinate to produce a distinct gametophytic generation. The prothallus (gametophyte) is tiny, from 0.5-2.0 mm in height and irregularly lobed or branched...The sterile stems are jointed, hollow, usually erect, and bear up to 20 whorls of slender branches. They are usually from 5-60 cm tall...The inconspicuous, scalelike leaves occur in whorls at the nodes and are connected at their bases...The rhizomes of field horsetail are branched and creeping. They are similar to the aerial stems except that they are not hollow. Storage tubers are produced on the rhizomes. (Plant Database)

Threats

Field horsetail is present in both seral and climax communities; its presence is largely dictated by edaphic conditions rather than shade or other factors. Field horsetail is an early colonizer on floodplain deposits. These communities are often destroyed by flooding before beingcan stabilized by willow establishment [62]. Field horsetail continues to be present through succession, occurring under more developed willow-alder communities, as an herbaceous layer dominant with meadow horsetail (Equisetum pratense) under open balsam poplar (Populus balsamifera)/thinleaf alder (Alnus tenuifolia) stands, and in the herbaceous layer of closed balsam poplar/white spruce communities.

Field horsetail is top-killed by most fires. The rhizomes are particularly resistant to fire because they are buried deep in the mineral soil...Field horsetail regenerates rapidly after a fire. The frequency of occurrence of field horsetail is usually unchanged or increased after fire. Gametophyte establishment requires the presence of moist, exposed mineral soils (as well as a source of spores). (Plant Database)

Reproduction

The main mode of reproduction of field horsetail is asexual; conditions for the production of gametophytes from spores are limited and relatively rare.

Asexual reproduction - Field horsetail spreads from extensive rhizomes. Even short segments of broken rhizomes (3 cm) will sprout. Overwintering buds develop at the nodes of the rhizomes.

Sexual reproduction - The spores of field horsetail are equipped with elaters, which are long appendages that expand and contract with changes in humidity. Elaters function to dig the spore into the soil surface and to tangle spores together, thereby creating a larger propagule and increasing the probability that prothalli will be close enough to ensure fertilization. Elaters may also aid in wind dissemination. Spores released by the strobiliferous stems are dispersed by wind or water. The spores are thin-walled, short-lived, and quickly germinate under moist conditions.

Strobiliferous shoot buds are initiated in July, August and into September. Vegetative buds are initiated in October and November. Strobiliferous buds elongate early in spring (March to May, depending on latitude), usually before the vegetative stems elongate. Emergence is earliest in dry sandy places, later in wet or clay soils. Spores are shed in early May in the Adirondack Mountains of New York. The strobiliferous shoots die after the spores are shed. Sterile stems emerge in May, producing branches after they are 3 to 5 inches (8-12 cm) in height. (Plant Database)

Species Distribution

Field horsetail is cosmopolitan in distribution. In North America it occurs from Newfoundland west to Alaska and south to Georgia, Alabama, Texas, and California. (Plant Database)

Citation

USDA Plant Database http://plants.usda.gov/characteristics.html USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America http://www.efloras.org/flora_page.aspx?flora_id=1 Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

Silvics of North America Burns, R.M., and B.H. Honkala. 1990. Silvics of North America (Volume 1: Conifers, Volume 2: Hardwoods). USDA Forest Service Agricultural Handbook 654.

Intermountain Herbarium http://intermountainbiota.org/portal/collections/harvestparams.php Consortium of Intermountain Herbaria. 2016. http//:intermountainbiota.org/portal/index.php. Accessed on February 04.

Burke Museum Plant Image Collection The plant image collection at the Burke Museum, University of Washington.

Jepson Manual http://ucjeps.berkeley.edu/eflora/ The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA., hardcover; 1600 pages. ISBN-13: 978-0520253124.

USGS Plant Species Range Maps http://esp.cr.usgs.gov/data/little/ Critchfield, W.B., and Little, E.L., Jr., 1966, Geographic distribution of the pines of the world: U.S. Department of Agriculture Miscellaneous Publication 991, p. 1-97. Little, E.L., Jr., 1971-1978, Atlas of United States trees, volume 1,3,13,17, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publications.

Photo from Smithsonian National Museum of Natural History.