In woodland of almost all kinds, preferring wooded ravines and beech and sugar maple woods. Infrequent to frequent throughout the state except on the crests of black oak and chestnut oak ridges, on the dunes, and in prairies. The sepals of this plant are usually green, but sometimes are rose purple.
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.