27. Cyperus squarrosus L.

Pl. 67 f–g; Map 271

C. aristatus Rottb.

C. inflexus Muhl.

Plants annual, tufted, lacking rhizomes and tubers. Aerial stems 3–20 cm long, erect to more commonly spreading, bluntly trigonous, smooth. Leaf blades 1–15 cm long, 0.5–2.5 mm wide (sometimes folded longitudinally and thus appearing narrower), shorter than to longer than the stems. Inflorescences of 1–3 spikes or less commonly irregular umbels with 1–3 sessile spikes and 1–3 rays, each ray smooth, ending in a spike. Inflorescence bracts 2–4, mostly much longer than the rays, spreading to ascending. Spikes 6–20 mm long, with 6–35 spikelets, ovoid to hemispherical, usually dense, the spikelets radiating in several planes, attached at the tip of the axis, the spikelet bases usually visible. Spikelets 4–10 mm long, narrowly oblong-elliptic, rounded to pointed at the tip, strongly flattened in cross-section, with 6–20 florets, the fruits and scales shed successively from the base to the tip, leaving the persistent (or mostly so) axis. Spikelet axis not winged. Spikelet scales 1.3–2.7 mm long, strongly overlapping, ascending to spreading, narrowly ovate, sharply angled along the back, long-tapered to a short, recurved awn at the tip, with 5–9 nerves, greenish brown to more commonly reddish brown, the midrib green. Stamen 1, the anther 0.2–0.3 mm long. Stigmas 3. Fruits 0.6–1.0 mm long, oblong-obovate in outline, 3-angled in cross-section, the surface finely pebbled, light brown to greenish brown or less commonly nearly black, shiny, often somewhat iridescent. 2n=48, 56, 64. May–October.

Common throughout Missouri (nearly worldwide in tropical and warm-temperate regions; in the New World, nearly throughout the U.S. and adjacent Canada south to South America and the Caribbean Islands). Margins of rivers, streams, ponds, and lakes, moist depressions of glades, bluff ledges, and upland prairies, and openings of upland forests; also roadsides, railroads, crop fields, fallow fields, pastures, and moist, open areas.

Cyperus squarrosus produces a pleasant, sweet odor when crushed or dried. This has been likened to the odor of sweet clover (Melilotus) hay or slippery elm (Ulmus rubra) bark.