Rhamnus cathartica and Frangula alnus; buckthorn [Rhamnaceae]  Tall shrubs or small trees (20-25’) usually with few to several stems arising from the base.  Grey to brown bark with prominent lenticels.  Alternate (sometimes opposite) leaves emerge very early in the spring and stay green long into fall and winter.  Leaves of R. cathartica (common buckthorn) are dull green and finely toothed, while those of F. alnus (glossy buckthorn) are glossy and toothless.  Inconspicuous flowers develop into prolific clusters of ¼” red-to-black berries in late summer and fall.  Introduced as ornamental hedges, both species have become aggressively invasive in many Wisconsin habitats.  [079]