8a. var. longispicatus (Britton) S.G. Sm.

Stigmas mostly 3. Fruits flattened and slightly triangular in cross-section (flat on 1 side, rounded but slightly ridged on the other). May–September.

Uncommon and widely scattered in Missouri (western U.S and adjacent Canada east to Illinois and Mississippi; Mexico, Caribbean Islands, South America). Margins of ponds and lakes, gravel bars and stream banks, and marshes.

Steyermark (1963) referred to plants with mostly 3 stigmas as Scirpus americanus var. polyphyllus (Boeck.) Beetle, but this name is of uncertain application (Koyama, 1963). For further discussion of this variety, see the treatment of var. pungens.