Horned wrack is closely related to other large brown intertidal seaweeds including bladder wrack and serrated wrack. However, Horned Wrack is restricted to growing in estuaries or near freshwater streams on the shore as it prefers a lower salt concentration. Horned Wrack does not have airbladders, but the side of the fronds are often inflated and branch out at the ends. 

Horned Wrack can be found in the upper parts of estuaries and similar habitats (e.g. coastal outflows) that are subjected to the influx of freshwater for part of the tidal cycle.