Cyperus entrerianus
Cyperus pumilus
woodrush flatsedge
low flatsedge
1–3, trigonous to roundly trigonous, (30–)40–65(–95) cm × (1–)2–3 mm.
trigonous, 1–35 cm × 0.5–1 mm, glabrous.
(1–)5–10, V-shaped, (10–)30–45(–70) cm × 3–7 mm.
flat, 5–20 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.
heads ± digitate, 8–26 mm diam.;
rays 1–6, 0.5–5 cm;
bracts 3–4, ± horizontal, flat, 3–18 cm × 1–2 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.
6–25, ovoid to linear-lanceoloid, compressed, 4–15 × 1–2 mm;
floral scales 8–28(–40), clear, laterally ribless, ovate, 1.4–1.6 × 0.8 mm, apex awned, awn excurved, 0.3–0.5 mm.
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 1–2;
anthers 0.2 mm;
styles 0.5 mm;
stigmas 0.3 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.
dark brown to black, sessile, obovoid, 0.6 × 0.4 mm, apex obtuse, apiculate, surfaces minutely punctate.
Cyperus entrerianus
Cyperus pumilus
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 pumilus is distinctive because it is our only distigmatic Cyperus with awned floral scales.
Cyperus hyalinus Vahl, a southeastern Asian and Australian species, has recently been collected in Miami-Dade County, Florida (Mears s.n., EIU, VSC). This is an aberrant species sometimes placed in the monotypic genus Queenslandiella as Q. hyalina (Vahl) F. Ballard; it differs from C. pumilus in having deciduous rachillae as well as deciduous floral scales.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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