3. Cornus drummondii C. A. Mey. (rough-leaved dogwood)

C. asperifolia Michx.

Svida asperifolia (Michx.) Small

Map 1608, Pl. 369 a–c

Plants shrubs or small trees 2–6 m tall, sometimes colonial. Twigs green to reddish brown, densely hairy when young, becoming glabrous or nearly so with age, the pith white to brown. Bark usually with shallow fissures, the ridges becoming divided into thin, irregular plates, grayish brown, usually with small, slightly raised, lighter dots. Leaves opposite, usually relatively evenly dispersed along the branches, the petiole 1.0–1.5 cm long. Leaf blades (4–)6–11 cm long, 3–7 cm wide, lanceolate to elliptic or broadly ovate, rounded or angled at the base, tapered to a sharply pointed tip, the surfaces moderately pubescent with mostly somewhat spreading, V-shaped or Y-shaped hairs, the upper surface moderately to strongly roughened to the touch, the undersurface softer-hairy and usually with microscopic white papillae, the lateral veins 3 or 4(5) pairs, these mostly arising from the basal half of the blade. Inflorescences appearing more or less umbellate, flat-topped to shallowly convex, the bracts absent or rarely a few at the branch points and these minute and scalelike, the flower stalks 2–8 mm long, hairy, becoming reddish brown to purplish brown as the fruits mature. Sepals 0.4–1.0 mm long. Petals 2.5–4.0 mm long, narrowly oblong-lanceolate, white to cream-colored. Style 2.5–3.5 mm long, relatively slender, not broadened toward the tip. Fruits 4–7 mm in diameter, spherical, white, occasionally mottled with dark blue. Stone smooth or inconspicuously grooved. 2n=22. May–June.

Common nearly throughout the state (New York to Kentucky and Georgia west to South Dakota and Texas). Banks of streams, rivers, and spring branches, margins of ponds and lakes, bottomland forests, mesic upland forests in ravines, bases, ledges, and tops of bluffs, margins of glades and upland prairies, marshes, and fens; also fencerows, old fields, margins of crop fields, railroads, and roadsides.

Cornus drummondii is perhaps the most common species of dogwood in disturbed habitats in Missouri and also tolerates somewhat drier conditions than do other members of the genus present in the state. It is unique among Missouri Cornus taxa in its roughened upper leaf surface, the secondary veins somewhat crowded toward the leaf base, and its white fruits. However, there is considerable variation in the degree of leaf roughening, which has led some botanists to speculate that hybrids between C. drummondii and other Missouri dogwoods are common. Such hybrids do occur but apparently are partially sterile and generally are confined to individual plants or small colonies (when the hybrid spreads vegetatively by root sprouts). Hybrids between C. drummondii and C. foemina ssp. racemosa were reported from southern Missouri north to Jackson County by Wilson (1965). Such hybrids have leaves that are only slightly roughened, with many of the hairs T-shaped and appressed rather than Y-shaped and spreading, and fruits (when produced) that are either white or light blue. For a brief discussion of putative hybridization between C. drummondii and C. amomum, see the treatment of that species.