Flowers on tall, hairy, leafless flowering stems (scapes) in open or dense terminal panicles. The flowers are greenish or yellowish green, sometimes tinged with red, small (just under ½ inch long),bell-shaped, the upper lobes longer than and drooping over the lower ones, with orange-tipped stamens slightly emerging from the flower. Blooms April–June. Leaves basal on long, hairy petioles, palmate, often deeply cleft with large teeth; 3–5 lobes, quite showy.
Similar species: There are 4 species of Heuchera in Missouri. Common alum root (H. americana) is absent from the northwest third of the state and parts of the Bootheel; it has smaller flowers and is common on bluffs and rocky woods. Small-flowered alum root (H. parviflora) grows on bluffs and rock outcrops in the Ozarks.; its leaves have rounded lobes. Maple-leaved alum root (H. villosa) is uncommon and known only from Shannon County.