Frangula alnus (Alder buckthorn)

Slender shrub with erect thornless branches; alternate untoothed leaves, turning yellow or red in autumn; 5-petalled flowers. Contain emodine, frangulanin, frangulin, and anthraquinones such as emodin. Emodin has been used as a laxative (in herbal remedies obtained through bark shavings), but is now used mainly as tool in toxicity studies. Small branch with ovate green leaves and single red berries.