Scirpus hallii of Michigan Flora.

Sandy/peaty open shores of lakes; sandy, intermittently moist swales and depressions.

The achenes of S. hallii tend to be more persistent than their scales and thus are conspicuous. This is is found in the same habitats as our Coastal Plain disjuncts, although it is of wider distribution. However, it is a rare plant that only appears sporadically in its habitat, and is known from throughout the eastern and central United States only from a few widely scattered colonies (McKenzie & Smith 2007).

Schoenoplectiella hallii is unusual in not only producing achenes from aerial spikelets, similar to our other species, but also bearing specialized achenes hidden singly inside the sheaths at the very base of the plant, at or below ground level. This is termed amphicarpy. These basal achenes are substantially larger, more clearly triangular, more strongly apiculate, and less strongly ridged than those from the aerial spikelets.