75.
Cyperus
refractus
Engelmann ex Boeckeler, Linnaea. 36: 369. 1870; based on Cyperus refrofractus Engelmann ex Steudel, Syn. Pl. Glumac. 2: 47. 1855, not (Linnaeus) Torrey 1848.
Herbs, perennial, cespitose, with inconspicuous, short rhizomes scarcely visible between culm bases. Culms basally cormlike, trigonous, 30—100 cm × 2—4 mm, glabrous. Leaves V-shaped to flat, 20—70 cm × 3—8 mm, adaxial surface, margins minutely scab-ridulous. Inflorescences: spikes loose, broadly ellipsoid to ovoid, 4—7 × 2—6 cm; rays 6—13(—16), 4—25 cm, glabrous; rachis 1.5—3 cm; bracts 3—6, horizontal to ascending at 30°, flat, 5—35 cm × 2.5—6 mm; rachilla persistent, wings 0.4—0.5 mm wide. Spikelets (13—)20—60(—74), linear, ± terete, (11—)13—25(—28) × 1.2—1.5 mm; distal spikelets spreading or ascending; floral scales persistent, (2—)3—6, stramineous, red-purple striate, laterally 3—5-ribbed, ovate-lanceolate, 4.5—5.3 × 1.2—1.5 mm. Flowers: anthers 1—1.5 mm; styles 1.5 mm; stigmas 1.5 mm. Achenes brown to purplish brown, oblong-linear (5—6 times long as wide), 2.6—3 × 0.5—0.6 mm, base cuneate, apex obtuse, surfaces puncticulate.
Fruiting summer (Jul—Aug). Sandy riverbanks, gravelly roadsides, pastures, disturbed places; 20—300 m; Ala., Ark., D.C., Ga., Md., Mo., N.C., Pa., S.C., Tenn., Va., W.Va.
Cyperus refractus is often mistaken for C. strigosus, which has shorter anthers (0.4—0.5 mm) and spreading, ± deciduous floral scales.
