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Invasive Species Identification Sheet - Glossy Buckthorn

Glossy Buckthorn (Frangula alnus Mill.)

Alternate Latin name: Rhamnus frangula L.

Alternate common names: Shining Buckthorn; Fen Buckthorn; European Buckthorn (also a common name of Rhamnus cathartica); European Alder (don't confuse with Alderleaf Buckthorn [Rhamnus alnifolia])
- shrub or small tree; bark has prominent white lenticels (raised corky areas)
- leaves generally alternate, 1"-3" long, with 8-9 pairs of veins; margins not toothed
- leaves glossy, may be hairy on the underside, especially on the midvein (use hand lens)
- leaf veins curve up to follow the leaf edges and stand out on the leaf underside
- tiny flowers, each with 5 whitish or greenish petals; flowers come out of leaf axils
- branches may have both flowers and fruit at the same time
- fruit is a drupe (berry-like) with 2-3 not-grooved seeds; eaten by birds, but poisonous to humans
- fruit first ripens mid-summer, but flowers continue to be produced so branches may bear fruit in different stages of ripeness (green,
  reddish, or purplish-black)
- buds are rust-colored and naked (covered with a shriveled up leaf instead of scales)
- branches finely hairy at the tips (on the last 1/2" - use hand lens)
- inner bark is yellow

Glossy Buckthorn has no spines or thorns. It grows in shade but does best in sun. It is particularly invasive at wetland margins or on limey soils. The deciduous leaves remain into late Fall, turning a light green or yellow color that stands out in the forest understory. In New England, don't confuse with the native shrub, Alderleaf Buckthorn (Rhamnus alnifolia L'Her.), which does have alternate leaves with 8-9 pairs of veins, but the leaves are toothed, leaf surfaces are puckered (like seer-sucker fabric), and the buds are scaly (not naked).