The main stem is erect, the bark smooth, of a blackish-brown colour, on the twigs ash-coloured. The smaller branches generally terminate in a stout thorn or spine, hence the ordinary name of Buckthorn, and the older names by which the shrub has been known: Highwaythorn and Waythorn. Gerard calls it Ram or Hart's Thorn. The leaves grow in small bunches on footstalks, mostly opposite towards the base of the young shoots, though more generally alternate towards the apex. They are eggshaped and toothed on the edges, the younger ones with a kind of soft down. In the axils of the more closely arranged leaves, developed from the wood of the preceding year, are dense branches of small greenish-yellow flowers, about one-fifth inch across, which are followed by globular berries about the size of a pea, black and shining when ripe, and each containing four hard, dark-brown seeds.