Equisetum laevigatum is a rush-like perennial that rises from an underground rootstock structure. Normally the plant dies back over the winter, but some populations in the southwestern USA have individuals that can overwinter. The plant manifests jointed rough stems which are closed at the joints. The stem roughness are a result of inclusions of silica. Each stem exhibits longitudinal grooves that run vertically. Each joint has a sheath which is a minute pointed leaf-like structure. The species usually occurs along moist drainages in sandy and gravelly substrates.

The narrow green stems can attain heights ranging from 30 to 150 centimeters. The stems are generally unbranched and are capped with rounded cone-shaped sporangia. Stomata occur in single lines; moreover, the spherical spores of this species are green.

Equisetum laevigatum A. Braun:
Canada (North America)
Mexico (Mesoamerica)
United States (North America)

Canada

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Equisetum laevigatum is broadly distributed across North America in including the entire western USA and Great Plains. The southeastern USA and New England are excluded from the range. In Canada, the taxon is widely found in the entirety of the southern half of Canada.

Aerial stems lasting less than a year, occasionally overwintering in the southwestern United States, usually unbranched, 20--150 cm; lines of stomates single; ridges 10--32. Sheaths green, elongate, 7--15 × 3--9 mm; teeth 10--32, articulate and usually shed early, leaving dark rim on sheath. Cone apex rounded to apiculate with blunt tip; spores green, spheric. 2 n =216.

Schaffner named this species Equisetum kansanum because he applied the name E . laevigatum to what we now know is the hybrid E . × ferrissii . The coarser-stemmed, occasionally persistent forms in the southwestern United States have been called Equisetum funstonii .

Equisetum funstonii A.A. Eaton, E. kansanum J.H. Schaffner

Holotype for Equisetum funstonii A.A. Eaton
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Verified from the card file of type specimens
Preparation: Pressed specimen
Collector(s): F. V. Coville & F. Funston
Locality: California, United States, North America

Cones maturing in spring--early summer. Moist prairies, riverbanks, roadsides; 1530--3500 m; Alta., B.C., Man., Ont., Que., Sask.; Ariz., Ark., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Ohio, Okla., Oreg., S.Dak., Tex., Utah, Wash., Wis., Wyo.; n Mexico including Baja California.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Species: 1
Species With Barcodes: 1

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure