13. Heuchera longiflora Rydberg in N. L. Britton, Man. Fl. N. States. 482. 1901.
Heuchera aceroides Rydberg ex Small; H. longiflora var. aceroides (Rydberg ex Small) Rosendahl, Butters & Lakela; H. scabra Rydberg
Herbs acaulescent; caudex branched. Flowering stems often leafy, 30-95 cm, glabrous or short stipitate-glandular. Leaves: petiole glabrous or short stipitate-glandular; blade (often variegated adaxially), broadly ovate to cordate, shallowly 5-lobed, 3-12 cm, base cordate or nearly truncate, lobes rounded to widely ovate, terminal lobes often elongated, margins dentate, apex acute or obtuse, surfaces glabrous or short stipitate-glandular, at least on veins. Inflorescences diffuse. Flowers: hypanthium strongly bilaterally symmetric, free 2.2-6.2 mm, green, gibbous-tubular, abruptly inflated distal to adnation to ovary, 6.6-12.6 mm, short stipitate-glandular; sepals inflexed (closing mouth of flower), darker green-tipped, equal, 2-3.7 mm, apex rounded; petals inflexed (closing mouth of flower), white, pink, or purple, spatulate, unlobed, 1.8-5.5 mm, margins often fimbriate; stamens 2.4 mm included to 0.7 mm exserted; styles included 1.3-5.3 mm, 1.5-2.5 mm, to 0.1 mm diam. Capsules ovoid, 5-13 mm, beaks divergent, not papillose. Seeds dark brown, ellipsoid, 0.5-0.9 mm. 2n = 14.
Flowering May-Jun. Rich, shaded woods and roadcuts over limestone substrates and outcroppings; 100-500 m; Ala., Ky., N.C., Tenn., Va., W.Va.
Heuchera longiflora is restricted to limestone outcroppings and is rare in all the states where it is found.