Halopteris scoparia (=Stypocaulon scoparium) is a brown algae characterized by a frond filiform, dark brown stiff tufts attached rhizoids. It has segmented filaments, each segment with longitudinal divisions and occasional secondary transverse divisions. The filaments are often densely packed, giving an appearance of a series of inverted cones.  Lower parts of main axes are often bare. Unilocular sporangia is formed in clusters on short branchlets in the axils of main branches.

This algae is Uncommon on southern and western coasts, rarer further north. Frequent in sandy pools.