common buckthorn (Rhamnus cathartica)

Detail of sub-opposite leaves: http://farm3.static.flickr.com/2121/1796895536_e6af08ecdf.jpgRhamnus: ancient Greek name for the buckthorncathartica: purgativeHabitat: FACU; has invaded the understory of woodlands across ChicagoStatus: All to prevalent in the Chicago RegionPlant: shrub or tree to 20'; bark has dark lenticelsBlooming: 7 May to 12 JunrFruit: blue-black berryLeaf: dentate edges, dull green.Photo sources: http://upload.wikimedia.org/wikipedia/commons/b/ba/240_Rhamnus_cathartica.jpg

Right: A typical scene -- hundreds of buckthorn sprouts at an undermanaged site. http://farm1.static.flickr.com/196/509274588_081d72fd19.jpg