Included in Scirpus smithii in Michigan Flora.

Sandy to mucky or boggy, sometimes marly, shores and hollows, especially where water levels have receded; frequently associated with Coastal Plain disjuncts such as Rhynchospora scirpoides and Fuirena pumila when in the same habitats.

Most specimens of Schoenoplectiella purshiana from Michigan have perianth bristles (var. purshiana). Plants without bristles (var. williamsii (Fernald) Hayas.) are known from fluctuating water level shorelines in only a few counties in the southwestern Lower Peninsula (Barry, Berrien, Cass, Kalamazoo, and Van Buren). Apparently almost never co-occurring with the bristled form; only at Daggett Lake, Barry Co., have both been collected (though in different years). There definitely seems to be a difference in the ecology and distribution of the two entities. 

Especially when plants are robust, the single involucral bract is often bent or even reflexed in Schoenoplectiella purshiana, while that of S. smithii is ± straight. Also, the bristles of S. purshiana, when present, are clearly tapered to a wider base and often longer than the achene. Bristles of S. smithii are about the same width for most of their length and are sometimes shorter than the achene.