Shrub 1 - 4 m tall Leaves: 7 - 12 cm long, egg-shaped to rounded with arching (arcuate) veins, slightly hairy above, hairy beneath. Flowers: borne in flat- to round-topped clusters to 6.5 cm long, white, small. Fruit: fleshy with a center seed (drupe), light blue, 6 mm long. Twigs: light yellow to green, sometimes with reddish purple patches.
Similar species: Several dogwood species are difficult to distinguish from each other. All of the following are shrubs with opposite leaves and arching leaf venation, but the twigs and fruit provide useful identification features. Cornus stolonifera has red to purplish red twigs that intensify in winter and flat- to round-topped clusters of white fruit. Cornus racemosa has tan to reddish brown twigs that become gray with age and round-topped to pyramidal clusters of white fruit on pinkish red stalks. Cornus obliqua has purple to yellowish red twigs covered in dense hairs and clusters of light blue fruit.
Flowering: late May to late June
Habitat and ecology: This species requires specialized habitats such as shaded rocky, clay, or dune slopes. Therefore, it is uncommon and becoming rarer in the Chicago Region.
Occurence in the Chicago region: native
Etymology: Cornus comes from the Latin word, cornu, meaning horn, referring to its hard wood. Rugosa comes from the Latin word meaning wrinkled.
Shrub 1-4 m, commonly more tree-like in form than no. 3 [Cornus sericea L.], often with a single main stem from the base; twigs glabrous or nearly so, light or yellowish-green, often shaded or mottled with red; pith white; lvs ovate to rotund, mostly 7-12 cm, abruptly acuminate, broadly cuneate or usually rounded at base, minutely scaberulous-strigose above, softly and loosely white-hairy to merely strigose beneath with hairs 0.5-1 mm; lateral veins 6-8 on a side; infl flat or slightly convex; fr light blue, 6 mm; 2n=22. Moist or dry, sandy or rocky soil, typically in better-drained sites than no. 3; Que. to n. Ont. and Man., s. to N.J., Pa., n. O., n. Ind. and Io., and in the mts. to Va. May-July. (C. circinata; Svida r.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Found in the counties indicated on the map. The reports for other counties are, no doubt, errors in determination. It is infrequent on the moist shady slopes in the dunes near Lake Michigan, on the high sandy bank of Pigeon River west of Mongo in Lagrange County and in a low sandy woods north of Pigeon River 3 miles east of Mongo, and on the crest of a wooded ridge along Sugar Creek about a mile east of the Shades in Montgomery County. The Montgomery county plant was found in a relict area with Pinus Strobus, Gaultheria procumbens, and Rhus typhina.