Northern Ontario Plant Database

Plant Description

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Cornus rugosa Lam.

En: roundleaf dogwood
Fr: bois de Calumet, cornouiller rugueux

Cornaceae (Dogwood Family)

The Genus Cornus: Woody Cornus (dogwood) species are medium to tall, deciduous shrubs, usually with opposite leaves and branches, except for Cornus alternifolia, which has alternate leaves. Dogwood leaves are broadly-elliptic with several pairs of parallel veins that curve towards the tip (apex) of the leaf. The numerous small flowers have parts in multiples of four (4-merous) and are arranged in large, flat-topped inflorescences.

General: A medium-sized shrub, to 3 m tall. Twigs yellowish- to reddish-green, streaked with purple, rough-textured; pith relatively large, white; buds greenish; leaf scars broadly-U-shaped, with 3 bundle trace scars.

Leaves: Opposite, simple, pinnately-veined, petiolate. Leaf blades ovate to orbicular, 7–15 cm long, 5–12 cm wide; light to dark green and rough above, with a dense covering of woolly, gray hairs beneath; the base rounded; apex abruptly pointed (acute); margins entire. Veins arranged in 7–9 pairs, curving towards the apex. Petiole 12–18 cm long.

Flowers: Bisexual, numerous, arranged in flat-topped clusters (cymes), 3–6 cm wide; flowers stalked. Calyx lobes 4, small; petals 4, creamy-white; stamens 4; the single pistil with an inferior ovary. Flowers bloom in early summer.

Fruit: a small ovoid to spherical, light blue to greenish-white drupe; about 6 mm long. Fruits mature in late summer.

Habitat and Range: sandy, gravelly, or rocky slopes, often growing in areas underlain by limestone bedrock. The roundleaf dogwood is also a temperate, northeastern North American species that occurs throughout southern and eastern Ontario; in northern Ontario it occurs farther north than the alternateleaf dogwood, but does not extend past 50°N (Soper and Heimburger 1982).

Internet Images: Webpage of Cornus rugosa from Wisconsin State Herbarium's Vascular Plant Species Database.

The Cornus rugosa webpage from the USDA Plants Database illustrates the nearly orbicular leaves of this dogwood.

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