Carolina alum-root

Heuchera americana Linnaeus var. caroliniana Rosendahl, Butters & Lakela, Minnesota Stud. Pl. Sci. 2: 59. 1936

Herbs acaulescent; caudex branched. Flowering stems leafy, 30-105 cm, short stipitate-glandular. Leaves: petiole glabrous or short stipitate-glandular; blade broadly ovate, shallowly 5-lobed, 3-10.5 cm, base cordate or nearly truncate, lobes rounded or ovate, margins dentate, apex acute or obtuse, surfaces glabrous or minutely stipitate-glandular on veins abaxially, glabrous or short stipitate-glandular adaxially. Inflorescences diffuse. Flowers: hypanthium weakly bilaterally symmetric, free 1.3-2.5 mm, green, subglobose, abruptly inflated distal to adnation to ovary, 2.8-4.5 mm, short stipitate-glandular; sepals erect, green-tipped, equal, 0.4-1.5 mm, apex rounded; petals erect, white or pink, broadly spatulate, unlobed, 0.6-1 mm, margins entire; stamens exserted 0.2-1.5 mm; styles included from 1 mm to exserted 1.1 mm, 1-3.5 mm, to 0.1 mm diam; (stigmas from 0.5 mm included to 1.1 mm exserted). Capsules ovoid, 4-7 mm, beaks divergent, not papillose. Seeds dark brown, ellipsoid, 0.5-0.8 mm. 2n = 14.

Flowering Apr-Jun. Rich upland woods on base-saturated substrates, basic dikes and basic rock outcroppings; 30-300 m; N.C., S.C., Va.

The geographic range of Heuchera caroliniana is contiguous with and appears to be a southern extension of that of H. pubescens. Heuchera americana var. americana occurs in counties adjacent to the range of H. caroliniana but they are sympatric only along the boundary; intergradation between the two is infrequent. Mixed populations of H. caroliniana and H. americana var. americana have not been seen.