Prairie Alumroot
Heuchera richardsonii affinis
Saxifrage family (Saxifragaceae)

Description: This native perennial plant consists of a rosette of basal leaves. The mature leaves are about 3-5" across, palmately lobed, and orbicular or slightly cordate in shape. Their margins are coarsely serrate or dentate, often with straight white hairs along the major veins on the underside of each leaf. The petioles are longer than the leaves. They have straight white hairs that are quite long and conspicuous. From the center of the rosette emerge several flowering stems that are 2-4' tall. These stems are without leaves and have straight white hairs like the petioles. Each stem terminates in a narrow panicle of green flowers. Sometimes the flowers have reddish tints when exposed to the sun. Each flower is about 1/8" long, consisting of a bottle-shaped calyx that is divided into 5 lobes. There are 5 inconspicuous petals within the calyx, while 5 stamens with orange anthers are exerted beyond the calyx. The blooming period is usually early summer, and lasts about a month. There is no floral scent. Small capsules develop, containing tiny unwinged seeds, which are dispersed by the wind. The central root stock is stout and short, dividing into coarse roots.

Cultivation: The preference is light shade to full sun, and mesic to dry conditions. This plant prefers rocky soil, but will grow in clay-loam,loam, or sandy soil. Once established, it is an easy plant to grow.

Range & Habitat: Prairie Alumroot occurs occasionally in the northern 2/3 of Illinois, but is rare or absent in southern Illinois. Habitats include upland areas of black soil prairies, hill prairies, gravel prairies, sand prairies, limestone glades, and rocky upland woodlands. Generally, Prairie Alumroot favors areas with poor rocky soil where there is reduced competition from taller plants.

Faunal Associations: Small bees pollinate the flowers, including Halictid bees and Plasterer bees (Colletidae). The seeds are too small to be of any interest to birds, while the relationship of this plant to mammals is uncertain.

Comments: This plant has a similar appearance to Heuchera americana (Common Alumroot). Generally, Prairie Alumroot has straight white hairs on the petioles of the leaves and the flowering stems, while Common Alumroot has short appressed hairs (lying against the flowering stems or petioles), or is devoid of conspicuous hairs. The flowers of Prairie Alumroot are slightly larger in size (about 1/8" long), while those of Common Alumroot are about 1/10" long. The flowers of Prairie Alumroot are often longer at the top than the bottom, while those of Common Alumroot are more symmetrical. Across different localities, there are significant variations in the characteristics of this plant, and different varieties have been identified. In Illinois, var. grayana has flowers that are strongly asymmetric (as described above), while var. affinis (as illustrated in the upper photograph) has flowers that are only slightly asymmetric. Plants with reddish leaves and silver markings have been introduced by the nursery trade, which are sometimes grown in flower gardens. The wild plant, however, isn't very showy.