16a. Anemone quinquefolia var. quinquefolia
Anemone nemorosa Linnaeus var. bifolia (Farwell) B.Boivin; A. quinquefolia var. bifolia Farwell
Aerial shoots 5-30 cm. Leaves: petiole 5-25 cm; terminal leaflet of basal leaves 1.5-4.5 × 1.4-3.7 cm, abaxially puberulous or glabrous, adaxially puberulous; lateral leaflets frequently 1×-lobed or -parted or unlobed; ultimate lobes 5-15 mm wide. Inflorescences: involucral bracts with terminal leaflet 1-5(-5.5) × 1-3 cm, base cuneate or ± oblique, margins crenate to serrate, sometimes incised, apex acuminate to acute, surfaces glabrous or puberulous; lateral leaflets frequently 1×-lobed or -parted, sometimes unlobed; ultimate lobes 5-20 mm wide. Flowers: sepals 6-25 × 4-8 mm; stamens 30-60. Pedicels 2-6(-8) cm in fruit. Achenes: body 3-4.5 mm. 2 n =32.
Flowering spring-early summer (Mar-Jun). Moist, open woods, thickets, clearings, streamsides, occasionally swampy areas; 30-1900 m; Alta., Man., N.B., N.S., Ont., Que., Sask.; Ala., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Pa., R.I., S.C., S.Dak., Tenn., Vt., Va., W.Va., Wis.
Anemone quinquefolia var. interior Fernald is an often used, although illegitimate, name for A . quinquefolia var. bifolia . This taxon, characterized by its villous flowering stems, is scarcely worthy of varietal recognition inasmuch as local populations may have plants referable to both var. bifolia and var. quinquefolia (C. S. Keener 1975b).
Intergradation of characteristics between Anemone quinquifolia var. minima and var. quinquefolia , and between var. quinquefolia and A . lancifolia frequently makes identification extremely difficult in the area where the taxa overlap.