This is close to aggregata; see notes under that name. Some immature specimens are difficult to distinguish. Both species are widespread in eastern states, and centered in midwestern regions on base-rich soils, but sparganioides is largely restricted to woodland (versus grassland). The sparganioides-aggregata group (including cephaloidea and gravida) are best distinguished from other species in section Phaestoglochin as follows (FNA 4, W): sheaths loose, membranaceous and fragile on the ventral side (versus tight), septate-nodulose and usually mottled or striped with green and white on the dorsal side (versus not so).