Aquatic and Wetland Vascular Plants of the Northern Great Plains
62. Cyperaceae, the Sedge Family
2. Carex L. -- Sedge
43. Carex retrorsa Schwein.
Densely tufted from short rootstocks; culms obtusely trigonous, 2-10 dm long.
Leaves soft, 4-10 mm wide; sheaths green or yellow-tinged and
conspicuously septate-nodulose dorsally, yellowish-brown and hyaline ventrally.
Spikes unisexual, the upper 1-4 staminate, the terminal one largest,
1.5-5 cm long, just above or protruding from the cluster of pistillate spikes;
lower spikes pistillate, sessile and aggregate or the lower 1 or 2 separate
and peduncled, cylindric, 1.5-6 cm long, 12-20 mm thick; bracts leaflike,
several to many times longer than the inflorescence; pistillate scales
obtuse to acuminate, much shorter than the perigynia. Perigynia widely
spreading to reflexed, yellow-green to green, shiny, subterete, ovoid, inflated,
5-10 mm long, 1/3 to 1/2 as wide, coarsely 7- to 9-nerved, tapering or contracted
to a smooth or serrulate beak 2-3.5 mm long, the teeth 0.5-1 mm long, straight;
achenes trigonous, 2-3 mm long; stigmas 3, the style strongly
S-curved toward the base. Jun--Aug. Swamps, bogs, springs, wet meadows, shores,
stream banks and wet woods; frequent from e and c ND to e SD, also the Black
Hills; (Que. and N.S. to B.C., s to NJ, IN, IA, SD and OR).