Heuchera americana hirsuticaulis
Saxifrage family (Saxifragaceae)
Description: This herbaceous perennial plant consists of a large tuft of basal leaves up to ½' tall, from which one or more flowering stalks develop that are 2–3½' tall. The blades of the basal leaves are 2½–4" across. They are more or less orbicular in overall shape, but with 5-9 lobes along their margins; these lobes are shallow and rounded. The blades are indented at the junction of the petioles, while their margins are coarsely crenate-dentate. The upper surfaces of the leaf blades are medium green and sometimes variegated; they have scattered short hairs and a rough texture. The slender petioles are light green and hairy; they are as long or longer than their blades. The tall flowering stalks are light green, terete, hairy, and without leaves. At the apex of each stalk, there is a narrow panicle of flowers about 3-8" long. The spreading branches of the panicle are light green and hairy, while the flowers are drooping. Each fully developed flower is 4.0–4.5 mm. long, consisting of a light green or reddish green calyx with 5 narrow lobes, 5 light green petals, 5 strongly exerted stamens with orange-red anthers, and 2 styles. The petals are smaller than the calyx and insignificant. The calyx is conspicuously swollen toward its base. The blooming period occurs from late spring to early summer and lasts about 3 weeks. There is no noticeable floral scent. Each flower is replaced by a small seed capsule that has 2 prominent beaks. There are numerous tiny seeds inside each capsule, which are small enough to be blown about by the wind. The root system consists of a crown with fibrous roots. The preceding description applies only to var. hirsuticaulis.
Cultivation: The preference is dappled sunlight during the spring, followed by light shade during the summer. The soil should be well-drained, mesic to dry, and loamy or rocky. This is primarily a foliage plant that can function as a ground cover if it is densely planted.
Range & Habitat: The native Woodland Alumroot is occasional in the southern half of Illinois, while in the northern half of the state it is rare or absent (see Distribution Map). Habitats include upland rocky woodlands, thinly wooded bluffs, and wooded slopes. This species is found in high quality habitats where oak trees are often present. The most commonly encountered variety of Woodland Alumroot within the state is var. hirsuticaulis.
Faunal Associations: The nectar and pollen of the flowers attract small bees, including Halictid bees (Halictus spp., Lasioglossum spp., & Augochlorella spp.) and the oligolectic Plasterer bee Colletes aestivalis. This latter bee is a specialist pollinator of Heuchera spp. Insects that prefer to feed on the foliage or juices of Heuchera spp. include the flea beetle Altica heucherae and the aphid Nasonovia heucherae. The bitter-tasting basal leaves are usually ignored by mammalian herbivores.
Photographic Location: An upland rocky woodland at the Portland Arch in west-central Indiana.
Comments: Woodland Alumroot and other native Heuchera spp. are related to the commonly cultivated 'Coral Bells' of horticulture. However, the flowers of the native species are usually green and less showy. Across its range, different varieties of Woodland Alumroot have been identified. Compared to the typical variety, the variety that has been described here (var. hirsuticaulis) has flowering stalks and petioles that are more hairy. Otherwise, they are very similar. Another variety that has been recognized in Illinois, var. interior, has smaller flowers (3.0–3.5 mm. long) than var. hirsuticaulis. Another species in this genus that is sometimes encountered within the state is Heuchera richardsonii (Prairie Alumroot). It differs from the preceding varieties of Woodland Alumroot by its longer asymmetrical flowers (5.0–9.0 mm.). The flowers of Woodland Alumroot are more symmetrical (one side of the flower is about as long as another side).