Hercules'-club

Zanthoxylum clava-herculis, known as Hercules' club, southern prickly-ash or toothache tree, is a spiny deciduous shrub or small tree of the citrus family Rutaceae, typically reaching 10 to 17 metres with a rounded crown. Its grey trunk is distinctive for the thick, pyramidal corky knobs 2 to 3 cm tall, each tipped with a stout spine, that stud the bark and larger branches. The leaves are alternate, glabrous, leathery and pinnately compound, 20 to 30 cm long with 7 to 19 ovate-lanceolate leaflets about 4 to 5 cm in length, exuding a pungent citrus-like aroma when crushed. Small, dioecious greenish-white flowers about 6 to 8 mm across with three to five petals are borne in terminal panicles to 20 cm long in spring, followed by two-valved roughened capsules 6 mm in diameter that split to expose shining black seeds. The species is native to the south-eastern United States, where it occurs in coastal woodlands, fence rows and forest edges, often spread by birds that consume the fruit.