Cyperus entrerianus
Cyperus sanguinolentus
woodrush flatsedge
purpleglume flatsedge
1–3, trigonous to roundly trigonous, (30–)40–65(–95) cm × (1–)2–3 mm.
± terete to roundly trigonous, 3–25(–60) cm × 0.3–2 mm, glabrous.
(1–)5–10, V-shaped, (10–)30–45(–70) cm × 3–7 mm.
1–3, V-shaped, 1–8(–15) cm × 1–2 mm.
heads loosely to densely globose-ovoid, (6–)10–12(–20) mm diam.;
rays 6–10(–12), 1–8(–12) cm; 2d order rays 1–4, 5–15(–23) mm;
bracts (5–)6–8(–10), ascending at 45–60(–75)°, V-shaped, (5–)15–40(–55) cm × (1–)3–7 mm.
spike 1, loosely ovoid, 7–14 × 8–20 mm;
rays (0–)1–4, to 2(–3) cm;
bracts 2–4, horizontal to ascending at 30(–45)°, V-shaped to flat, 1–8(–18) cm × 0.5–1.5(–2) mm.
(1–)30–50(–65), greenish white, linear to broadly ellipsoid, flattened, 4–6.5 × 1.8–3.2 mm;
floral scales (10–)16–20(–26), laterally clear, pale green, off-white, or light brown, medially green or light brown, laterally weakly 1-ribbed, medially 2-ribbed, basally 2-keeled, oblong-lanceolate, (1.2–)1.4–1.6(–1.8) × (0.7–)0.8–1 mm, apex acute, mucronate, distally glabrous or scabridulous.
3–5(–14), oblong to linear-lanceoloid, 8–18 × 2–2.6(–3) mm;
floral scales (6–)10–26(–32), laterally clear to light brown, sometimes with purplish margins, medially light brown, 2-keeled, laterally ribless, medially 2–3-ribbed, oblong to ovate, 1.9–2.2(–2.7) × 1.8–2.3 mm, apex obtuse.
stamen 1;
anthers ellipsoid, 0.6–0.7 mm, connective apex acute, 0.1–0.2 mm;
styles 0.2–0.4 mm;
stigmas 0.4–0.6 mm.
stamens 3;
anthers ellipsoid, 0.3–0.6 mm, connective not prolonged;
styles 0.6–1 mm;
stigmas 1–1.5 mm.
brown, stipitate, ellipsoid to narrowly ellipsoid, broadly rounded or contracted basally, gradually tapered toward apex, 0.9–1.1 × 0.3–0.4 mm, stipe 0.1 mm, apex acute, surfaces finely reticulate.
brown, ± stipitate, obovoid to ovoid, 1–1.4 × 0.6–0.8 mm, apex truncate, apiculate, surfaces minutely punctate.
Cyperus entrerianus
Cyperus sanguinolentus
Cyperus entrerianus is a recent introduction in the southern United States (earliest collection from Pensacola County, Florida, Brinker 413, MO in 1941). It has been confused with C. luzulae. The species that Boeckeler had first described 50 years earlier was accepted by G. Kükenthal (1935–1936). Cyperus entrerianus was accepted as a variety of C. luzulae by A. B. Ayers (1946); M. F. Denton (1978b) considered C. entrerianus a synonym of C. luzulae, stating that the features of these two taxa merged so completely throughout their geographic ranges that C. entrerianus could not be given specific status. Cyperus luzulae in the strict sense does not extend northward to North America.
Morphologic differences between Cyperus entrerianus and C. luzulae are as follows (G. C. Tucker 1994). Cyperus entrerianus has culms 40–75 cm; inflorescence bracts ascending at 45–60°; primary rays ascending at 45–60(–75)°; 2d order rays present; heads of spikelets loosely globose-ovoid, light greenish white to golden brown; rachilla dark red with stramineous scale scars; and scale apices acute. Cyperus luzulae has culms 20–40 cm; inflorescence bracts approximately horizontal; primary rays ascending at 15–30°; 2d order rays absent; heads of spikelets densely oblong to pyramidal, bright to dull white; rachilla green throughout; and scale apices rounded.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Cyperus sanguinolentus is the only rhizomatous, distigmatic Cyperus in the eastern United States. An early collection from Louisiana was described as C. louisianensis, supposedly endemic. Recent field work and morphometric studies convincingly showed it to be an introduction of the Asian C. sanguinolentus) (J. R. Carter and C. T. Bryson 2001.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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