Sterile stems ±prostrate, irregularly rooting, flattened, the lvs of the lower side twisted into an ascending position; lvs 8-10-ranked, linear-subulate, mostly entire, 5-7 נ0.5-0.7 mm; fertile stems few, erect, to 1 dm, 1 mm thick; sporophylls ascending or spreading, crowded into a sessile terminal cone 1.5-5 cm נ6-12 mm, all except the lower abruptly expanded near the base and usually with a single pair of sharp teeth near the expansion, otherwise like the lvs; sporangia subglobose, 1-1.3 mm wide; spores 43 microns or more in diameter, the sides convex, the outer face wavy-reticulate, the commissural faces papillose, the commissures sunken in deep furrows; 2n=156. Acid soil of bogs, shores, and meadows, often in seasonally inundated sites; circumboreal, s. to Md., sw. Va., O., Wis., Minn., and Calif.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.