Herbs caulescent; caudex branched. Flowering stems 9-30 cm, short or long stipitate-glandular, viscid. Leaves: petiole (7-22 cm), densely long stipitate-glandular; blade pentagonal to septagonal, deeply 5-lobed, 6.3-17 cm, base deeply cordate, lobes rounded, margins crenate, apex obtuse, surfaces long stipitate-glandular abaxially, glabrous adaxially except long stipitate-glandular near margins, viscid. Inflorescences dense. Flowers: hypan-thium radially symmetric, free 0.3-1.4 mm, white to pink, hemispheric, 2.5-4.2 mm, densely long stipitate-glandular; sepals somewhat spreading, green- or red-tipped, equal, 0.7-2 mm, apex rounded or truncate, (medium to long stipitate-glandular); petals spreading, white, oblong-lanceolate, (clawed), unlobed, 2-4 mm, margins entire; stamens exserted 0.4-2.5 mm; styles exserted to 2 mm, 1.5-4 mm, 0.1+ mm diam. Capsules ovoid, 4-8 mm, beaks divergent, not papillose. Seeds black, broadly fusiform, 0.4 mm. 2n = 14.
Flowering Mar-May. Exposed cliffs; of conservation concern; 0-500 m; Calif.
Heuchera maxima is found on the northern Channel Islands (Anacapa, Santa Cruz, Santa Rosa), Santa Barbara County.
Heuchera maxima is in the Center for Plant Conservation´s National Collection of Endangered Plants.