Plants often ascending, shoots 0.4-1.5 dm. Leaf blades glaucous abaxially, green adaxially, usually narrowly elliptic to elliptic, rarely oblong, 5-18 m 2-55 mm, margins entire, slightly revolute. Inflorescences in axils of leaflike bracts at base of current year´s shoots. Pedicels nodding, slender, 2-3 cm, bracteolate; bracteoles 2, greenish white, scalelike, 1-2 mm wide. Flowers: calyx lobes relatively small; corolla strongly reflexed at anthesis, white to pink; filaments hairy; anther tubules 1-2 mm. Berries red to pink, 9-14 mm diam., smooth. 2n = 24. Flowering late spring-early summer. Bogs, swamps, mires, wet shores and headlands; 0-1400 m; St. Pierre and Miquelon; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que.; Conn., Del., D.C., Ill., Ind., Maine, Md., Mass., Mich., Minn., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis.; introduced in Europe. Vaccinium macrocarpon is introduced and escaping elsewhere (British Columbia, Oregon, Washington) with respect to its normal range in eastern North America.
From Flora of Indiana (1940) by Charles C. Deam
In boggy and marshy places, usually associated with sphagnum. Formerly there were large areas of "cranberry marshes" in Indiana but now the species has become rare.
Evergreen trailing shrub with very slender stems; lvs leathery, subsessile, elliptic-oblong, 5-15 mm (the largest usually > 1 cm), rounded at the tip, flat or scarcely revolute; fls 2-6 in a cluster, solitary in the axils of the reduced lower lvs of a normal branch; pedicels 1-3 cm; bracteoles above the middle of the pedicel, green, 2-4 נ1-2 mm; cor white to pink, 1 cm wide, deeply 4-cleft, the lobes strongly reflexed; styles 5-7 mm; fr red, 1-1.5 cm, tart; 2n=24. Bogs; Nf. to Man., s. to Va., O., and n. Ill., and locally in the mts. to N.C. and Tenn. June-Aug. (Oxycoccus m.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.