Trichophorum cespitosum subsp. cespitosum

Scirpus cespitosus L. var. callosus Bigel. Fl. Bost
ed. 2, 21. 1824.
Scirpus luteus Gilib. Exerc. Phyt. 2: 513. 1792.
Scirpus obtusus Bigel. New Engl. Jour. Med. 5: 335. 1816.
Scirpus bracteatus Bigel. New Engl. Jour. Med. 5: 335. 1816.
Aploslemon bracteatum Raf. Am. Mo. Mag. 1: 441. 1817.
Trichophorum auslriacum Palla, Ber. Deuts. Bot. Ges. 15: 468. 1897.
Scirpus caespitosus B. austriacus Asch. & Graebn. Syn. Mitteleur. Fl. 2 2 : 300. 1904.
Scirpus austriacus Asch. & Graebn.; Lindm. Sv. Fanerogamfl. 117. 1918.
Scirpus cespitosus var. delicatulus Fernald, Rhodora 23: 25. 1921.
Densely cespitose perennial, fibrous-rooted, forming hard, close mats or occasionally soft tussocks on wet, calcareous banks; culms 1-3.5 dm. high, 1 mm. broad, slender, green, erect, terete, with 5 parallel grooves, clothed at the base with brown, gray, or black, persistent, indurate, imbricate sheaths; sheaths scale-like, mucronate, the uppermost green and having a smooth blade 5-8 mm. long, blunt at the tip, the orifice 0.5-1.5 mm. long, usually with a firm, abruptly-contracted, purple-dotted border; spikelet 4 mm. long, 2 mm. broad, solitary, terminal, light brown, 2-4-flowered ; outer scales 5-7 mm. long, 3.5 mm. broad, bearing a broad, smooth, green, blunt awn exceeding the spikelet; inner scales less prominently awned or merely acute; bristles 6, white or brown above, smooth, very fragile, surrounding and usually exceeding the achene; stamens 3; style 5 mm. long, trifid, barbellate; achene 1.5 mm. long, 0.75 mm. broad, dark brown, trigonous, smooth, short-pointed.
Type locality: White Mountains, New Hampshire.
Distribution: Acid peat of the northern tundra, and localized southward on mountain tops; North America, south in the mountains to Georgia, Illinois, Utah, and Washington; northern Europe.