Hercules' club blooms in early spring. The panicles of pale green flowers are borne terminally—at the end of the branches. Each flower is followed by a follicle, a fruit that dries and splits to reveal a shiny black seed.

Young Hercules' clubs have thorns on the trunk and branches. As the tree ages, the bark overgrows the thorns forming odd corky bumps. Eventually, the tips of the thorns will either break off or be completely buried within the bark.

The leaves are pinnate with seven to nine leaflets. The leaflets are deep green and shiny; the petioles are red and a red spine is usually present on the rachis between each pair of leaflets.

Zanthoxylum are members of the Rutaceae, the rue family, and like their cousins the citrus, all parts are aromatic. Hercules' club smells and tastes like bitter lime. If the thorns do not deter an herbivore, the taste will. One seldom sees more than a few chewed leaves on the tree.

One insect, though, relishes Hercules' club: the larvae of the giant swallowtail butterfly (Papilio cresphontes). All stages of the caterpillar, called an orange dog, look like a wet, fresh, brown and white bird dropping. Birds avoid the caterpillar on appearance only.

But appearance does not deter small predators like ants. Then a defensive organ, an osmeterium, comes into play. This forked scent horn emerges from the head, bends toward the offender, and emits soup of smelly, obnoxious organic acids.

(Compiled from: "Zanthoxylum", Hortus Third, Staff L.H. Bailey Hortorium, NY State College of Agriculture and Life Sciences, Cornell University, Macmillan, NY, 1976; "Giant Swallowtail", Florida's Fabulous Butterflies, Thomas C. Emmel and Brian Kenney, World Publications, Tampa; and personal observations)