Equisetum arvense L.
Common Name: COMMON HORSETAIL
Coefficient of Conservatism: 0
Coefficient of Wetness: 0
Wetness Index: FAC
Physiognomy: Nt Fern Al

Ubiquitous in a wide range of sunny or shaded habitats except very wet and very dry sites, including fields, forests, ditches, shores, meadows, roadsides, railroad embankments; sometimes weedy in yards and gardens.


Normally dimorphic, the fleshy pale pinkish-brown fertile stems appear in April or May, quickly shed spores, and die down soon afterwards. They are a striking feature of some early spring roadsides and fields. The green stems appear slightly later and last all summer. Sun and shade forms of the green stems may look very different, with shade forms being very graceful with long spreading branches, these occasionally (but never regularly) branched again. Plants of paths and other areas with heavy trampling may be spreading or even essentially prostrate.

Rarely, probably mostly stimulated by injury, the green stems of E. arvense will bear a terminal cone. These plants may simulate the hybrid E. ×litorale (see below), but differ in having a much narrower central cavity, ca. 1/4 the stem diameter, and also not occurring in the typical wetland habitat of E. ×litorale. Very rarely, the pinkish-brown fertile shoots may become green and even grow branches, thus simulating the habit of Epratense or Esylvaticum. From E. sylvaticum they differ in lacking the coppery sheath teeth and from E. pratense they differ in lacking stem papillae. See the key for additional distinctions.

Equisetum ×litorale (E. arvense × E. fluviatile), a rather uncommon hybrid, is known in Michigan from Grand Traverse, Mackinac, Monroe, Oakland, St. Clair, Washtenaw, and Wayne Counties. It resembles a large E. arvense, but with green shoots bearing a terminal cone and having a central cavity about 1/ 2 to 3/4 as wide as the stem.

Locations

Alcona County
Alger County
Allegan County
Alpena County
Antrim County
Arenac County
    Including Charity Island
Baraga County
Barry County
Bay County
Benzie County
Berrien County
Branch County
Calhoun County
Cass County
Charlevoix County
    Including Beaver Island
Cheboygan County
Chippewa County
    Including Drummond Island
Clare County
Clinton County
Crawford County
Delta County
Dickinson County
Eaton County
Emmet County
Genesee County
Gladwin County
Gogebic County
Grand Traverse County
Gratiot County
Hillsdale County
Houghton County
Huron County
Ingham County
Ionia County
Iosco County
Iron County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
    Including Manitou Islands
Lenawee County
Livingston County
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Macomb County
Manistee County
Marquette County
Mason County
Mecosta County
Menominee County
Midland County
Missaukee County
Monroe County
Montcalm County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ogemaw County
Ontonagon County
Osceola County
Oscoda County
Otsego County
Ottawa County
Presque Isle County
Roscommon County
Saginaw County
Sanilac County
Schoolcraft County
Shiawassee County
St. Clair County
St. Joseph County
Tuscola County
Van Buren County
Washtenaw County
Wayne County
Wexford County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 12, 2017. http://www.michiganflora.net/species.aspx?id=1197.