Dogwood family (Cornaceae)
Description: This woody shrub is 8-15' tall; it has a rounded shape and branches frequently. The bark of the trunk and larger branches is gray, while smaller branches are brown and smooth. Young twigs are hairless and red, becoming dark reddish brown with age. The pith of the twigs is white. The opposite leaves are up to 3½" long and 2" across; they are ovate to ovate-lanceolate and smooth along their margins. Upper leaf surfaces are medium to dark green and hairless, while lower leaf surfaces are a slightly lighter shade of green and hairless to nearly hairless. The slender petioles of the leaves are up to 1" long and hairless to nearly hairless. Like the leaves of other Cornus spp. (Dogwoods), the lateral veins of the leaves curve away from the petioles. Young branches bear compound cymes (or flat-headed panicles) of white flowers about 1½–3" across. The stalks of each cyme are hairless. Each flower has 4 white petals, a tubular green calyx with 4 tiny teeth, 4 stamens, and a pistil with a central style. The petals are linear-lanceolate in shape. The flowers have an unpleasant odor. The blooming period occurs during late spring to early summer and lasts about 2-3 weeks. The flowers are replaced by 2-seeded fleshy drupes. At maturity, each drupe is about ¼" across and it is pale blue to blue. Each large seed (stone) is globoid in shape and fairly smooth. The root system consists of woody branching taproot; vegetative offsets are sometimes produced from underground runners. During the fall, the leaves assume attractive red-burgundy to purple colors.
Cultivation: Stiff Dogwood prefers light shade to full sun, wet to mesic conditions, and a loamy soil containing organic material.
Range & Habitat: The native Stiff Dogwood is uncommon in the southern half of Illinois, and absent in the upper half of the state (see Distribution Map). It is possible that this dogwood is more common than official records indicate because it can be easily confused with similar species. Habitats include low woodlands, damp thickets, low areas along streams, and swamps. This dogwood prefers moist partially shaded areas.
Faunal Associations: The nectar and pollen of the flowers attract a wide variety of insects, including long-tongued bees, short-tongued bees, wasps, flies, butterflies, and beetles. An Andrenid bee, Andrena fragilis, is a specialist pollinator (oligolege) of Cornus spp. (Dogwood shrubs). Many insects feed on the foliage and other parts of Dogwood shrubs: These include the caterpillars of the butterfly Celastrina ladon (Spring Azure) and the caterpillars of several moths (see Moth Table). Other insects that feed on these shrubs include leaf beetles, flea beetles, long-horned beetles, aphids, and plant bugs; see the Insect Table for a listing of these species (excluding Lepidoptera). The drupes are readily eaten by upland gamebirds, some ducks, and many songbirds (see Bird Table); they are also eaten by the Black Bear, Raccoon, Gray Squirrel, Fox Squirrel, Eastern Chipmunk, and White-Footed Mouse. The foliage and twigs are browsed by the White-Tailed Deer and Cottontail Rabbit, while the Beaver both feeds on the branches and uses them in the construction of its dams and lodges.
Photographic Location: A shrubby area of Meadowbrook Park that is near an intermittent stream.
Comments: For some strange reason, Stiff Dogwood has received less attention than other dogwoods (Cornus spp.), even though it is reasonably attractive and probably easy to grow. This species differs from other dogwoods by its pale blue to blue drupes, hairless or nearly hairless leaves that are green on both sides, and hairless red twigs with white pith. In many ways, it resembles the better-known Red-Osier Dogwood (Cornus sericea), except the latter species has white drupes and a more northern distribution. Another species with blue drupes, Cornus obliqua (Silky Dogwood), has more slender leaves that are whitened on their undersides from fine hairs. Yet another species with blue drupes, Cornus amomum (Swamp Dogwood), has leaves with brownish hairs on their undersides and its twigs have brown pith. This latter species is restricted to the southern tip of Illinois. A scientific synonym of Stiff Dogwood is Cornus stricta.