Distribution: Alaska to Oregon, east across southern Canada and the northern tier of states in the United States.
Habitat: Shallow water, marshes and bogs, along muddy shores, from the lowlands to moderate elevations in the mountains.
Conservation Status: Not of concern
Rhizomatous annual, the stems not dimorphic, up to 1 m. tall, shallowly 9- to 25-ridged and grooved, the ridges smooth; stomata in a single broad band in each furrow; central cavity large, more than 3/4 the diameter of the stem; sheaths green, 4-9 mm. long, with persistent, sharp, black teeth 1.5-3 mm. long.
Branches none to many and whorled, 4- to 6-angled, simple, the first internode shorter than the stem sheath.
Cone short-pedunculate, blunt, deciduous.