Erect, to 7(-10) dm from slender rhizomes; lvs oblong- ovate, 6-12 cm, usually not more than about half as wide, acuminate, very shallowly sinuate-denticulate, rounded or barely subcordate at base; petioles subterete; infls many-fld, to 2 dm, elongating early so that the open fls as well as the frs are well spaced; pedicels filiform, spreading, finally reflexed, 3-6(-10) mm, glandular-pubescent; sep 2-2.5 mm, glabrous or glandular-pubescent; pet 2.5-4 mm, bilobed less than half-length; anthers 0.7-1 mm; stigma shallowly bilobed; disk prominent, 0.2-0.4 mm high; fr 3.5-5 mm, equally bilocular, each half normally with 3 large and 2 small rounded ridges separated by narrow furrows; 2n=22. Moist woods, interruptedly circumboreal, in Amer. from N.S. and s. Que. to s. Man., s. to Ga., La., and Okla. June-Aug. Ours is var. canadensis L. (aka as C. canadensis [which see]; C. quadrisulcata, properly an Asian var.) A sterile but vegetatively vigorous hybrid between our spp. is vegetatively intermediate and has unequally bilocular frs; the infl elongates early as in no. 1 [Circaea lutetiana L.] The name C. ةntermedia Ehrh. was based on the European hybrid C. alpina var. alpina נlutetiana var. lutetiana.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.