Equisetum laevigatum - (image 1 of 4)
Taxonomy
Family: Equisetaceae
Synonymous with E. kansanum. As a variety of E. hyemale it would be considered var. intermedium A.A. Eaton.
Habitat
Open wet places.
Associates
Distribution
Southern Ontario, western NY, OH, WV, IL, OK, and TX, west from Southern British Columbia to Baja CA.
Morphology
Fertile and sterile stems alike, produced annually, to 1 m, with mostly 16-32 smooth or inconspicuously wrinkled ridges, sometimes fewer, typically unbranched; central cavity more than half the diameter of the stem; sheaths green, 7-15 mm, typically black at the apex only, or with the lower ones sometimes black at the base or throughout; teeth of the sheath dark, scarious-margined, soon deciduous. Strobilis 1-2.5 cm, short-pedunculate, typically blunt or sometimes inconspicuously short-apiculate.
Notes
Strobilli produced in June
Wetland indicator: Facultative Wetland
The stomata of this species occur in two lines in each furrow, whereas those of E. fluviatile occur in a single line. Can hybridize with E. hyemale and E. variegatum.
References
Gleason, Henry A.
and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States
and Adjacent Canada. Second Ed.
The New York Botanical Garden. Bronx, NY
Swink, F. and G.
Wilhelm. 1994. Plants of the Chicago Region.
Indiana Academy of Science. The Morton Arboretum. Lisle, Illinois.
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Michael Hough © 2010 |