Plant Family: Rhamnaceae
Growth Form: Shrub to small tree, rarely reaching 6 meters.
Leaves: Opposite to sub-opposite, simple, elliptic, with small teeth, the curved veins parallel the leaf margins; spur branches with clustered leaves are common; many twigs end in a thin, sharp thorn.
Bark: Dark brown with yellow inner bark (use a small knife).
Flowers: Small, greenish white, with four petals, found in short clusters in the leaf axils.
Fruits: Black, berry-like drupes, held in heavy clusters in the leaf axils.
Habitat: Fencerows, wood edges, meadows, roadsides and other disturbed sites; tends to form thickets in both wet or dry soils.
Similar Species: Glossy Buckthorn, in the same plant Family, has alternate, untoothed leaves, no spur branches, and lacks thorns at the twig ends.
Range: Found throughout New England and much of the U. S. and Canada.
Comments: Common Buckthorn is a European species that was introduced in the late 18th century as an ornamental. It is now widespread and classified as invasive in several states. The specific name references the mildly poisonous seeds, that cause gastrointestinal distress; they are avoided by mammals, but eaten by birds, who disperse the seeds to new habitats.
