J. Bot. (Schrader) 1800(2): 110. 1801.
Trophophore stalk 0–1 mm; blade dark green, oblong, 1-pinnate, to 10 × 4 cm, thick, fleshy. Pinnae to 9 pairs, spreading, mostly overlapping except in shaded forest forms, distance between 1st and 2d pinnae not or slightly more than between 2d and 3d pairs, basal pinna pair approximately equal in size and cutting to adjacent pair, broadly fan-shaped, undivided to tip, margins mainly entire or undulate, rarely dentate, apical lobe usually cuneate to spatulate, notched, approximate to adjacent lobes, apex rounded, venation like ribs of fan, midribs absent. Sporophores 1–2-pinnate, 0.8–2 times length of trophophore. 2n =90.
Phenology: Leaves appearing in spring, dying in latter half of summer.
Habitat: Open fields, occasionally forests in southern occurrences
Elevation: 0–3700 m
Greenland, St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon, Alaska, Ariz., Calif., Colo., Idaho, Maine, Mass., Mich., Minn., Mont., Nev., N.H., N.Mex., N.Y., Oreg., Pa., S.Dak., Utah, Vt., Wash., Wis., Wyo., s South America, Eurasia, Pacific Islands in New Zealand, Australia.
Botrychium lunaria grows with many other species of Botrychium, occasionally hybridizing with them. This species, geographically the most widespread of the moonworts, has notably uniform morphology.