In the shallow-water moat of a poor fen on a floating mat.
Leaves triangular in cross-section. Inflorescence unbranched. Heads frequently supra-axillary and opposite the bract above. At least the distal heads clustered. Consistently with only a single staminate head.
S. emersum is similar but has more staminate heads. Flora of North America also notes that the fruit of S. emersum has beaks 2-4.5mm long versus 1.5-2mm in S. glomeratum.
It would seem that this species has not been recorded for Langlade Co.