Shrubs of Wisconsin

Zanthoxylum americanum Mill.
northern prickly-ash
Family: Rutaceae
shrub
branch
leaf
female flowers
male flower
fruit
leaf underside
fruit
seeds
bark
twig with bud and thorns
thorn on underside of leaf midrib
 

The shrub Zanthoxylum americanum has compound, alternate leaves and stout, paired thorns at each node. The only other woody species in our flora with that combination is the tree Robinia pseudoacacia (black locust). Zanthoxylum can be distinguished by its pointed leaflets and the presence of a few thorns on the underside of the leaf midrib. Robinia pseudoacacia has blunt tipped leaflets and no thorns on the leaf midrib. Also the buds are very different. The buds of Robinia pseudoacacia are hidden beneath the leaf scar, while those of Zanthozylum are large, covered with reddish hairs and easily visible above the leaf scar.

 


known Wisconsin distribution

Acknowledgments

Contact the author