Scirpus atrovirens Willd.

Scirpus atrovirens Wilid. Enum. 79. 1809
? Scirpus reticulatus Lam. Tab. Encyc. 1: 142. 1791.
Holoschoenus atrovirens Link, Hort. Berol. 1: 293. 1827.
Scirpus sylvaticus var. atrovirens A. Gray, Man. ed. 2, 500. 1856.
Scirpus sylvaticus var. sychnocephalas S. N. Cowles, Am. Nat. 3: 101. 1869.
Scirpus georgianus Harper, Bull. Torrey Club 27: 331. 1900.
Scirpus atrovirens var. pycnocephalus Fernald, Rhodora 8: 163. 1906.
Scirpus atrovirens i. sychnocephalus Blake, Rhodora 15: 161. 1913.
Scirpus atrovirens var. georgianus Fernald, Rhodora 23: 134. 1921.
Scirpus atrovirens var. georgianus subvar. viviparus Farwell, Am. Midi. Nat. 11: 72. 1928.
Scirpus atrovirens var. georgianus f. viviparus M.-Victorin, Proc. & Trans. Roy. Soc. Canada III.
23': 267. 1929. Scirpus atrovirens i. proliferus F. J. Herm. Rhodora 40: 77. 1938. Scirpus atrovirens var. Jlaccidifoliiis Fernald, Rhodora 40: 396. 1938.
Scirpus atrovirens var. georgianus f. cephalanthus Fernald, Rhodora 45: 296. 194 v
Scirpus atrovirens var. georgianus f. angustispicatus Fernald, Rhodora 45: 296. 1943.
Fibrous-rooted perennial; culms 0.8-1.5 m. high, stout, 1-1.5 cm. thick at the base, 2-3 mm. broad at the summit, sharply trigonous, smooth, green; sheaths long, green, drying brown, often nodulose, the blades pale green, 7-15 mm. broad, to 5 dm. long, equaling or exceeding the culm, scabrous on the margins and midrib, tapered to the blunt tip; umbel terminal, compound, the primary rays terete, minutely scabrous; spikelets in glomerules at the end of shorter, secondary rays, the glomerules usually few but occasionally very numerous and forming a densely packed head as much as 12 cm. long; spikelets dull greenish-brown or rufescent, narrowly ovoid to cylindric, 3.5-8 (rarely 10) mm. long, in glomerules of 10-30, often viviparous; scales 1.5-2 mm. long, loosely spreading, the margins greenish-black, the midrib tapered to a scabrous, mucronate tip; bristles 6 or fewer, sparsely to strongly retrorsely barbed, white, nearly straight, about equaling the achene or rarely absent; style trifid, reddish; achene ca. 1 mm. long, white, obovoid-oblong, trigonous, conspicuously pointed.
Type locality: "In America boreali."
Distribution: Meadows and bogs; Newfoundland to Saskatchewan, south to Georgia and Texas.