Cyperus strigosus

This native perennial flatsedge is ¾–3' tall and unbranched. The culm is 3-angled, glabrous, and rather stout. A few leaves develop along the lower half of the culm; their blades are up to 1½' long and ½" across, medium green, and glabrous. There is a deep channel along the central midrib of each leaf blade. The lower leaves often wither away before flowering occurs. The inflorescence consists of an umbel or compound umbel of floral spikes that spans several inches across. A typical inflorescence consists of 1-2 sessile spikes and 3-5 spikes on stiff peduncles (or rays) up to 4" long. Some of these spikes may have 1-2 lateral spikes projecting from each of their bases; these lateral spikes are shorter. At the base of the inflorescence, there are 3-8 leafy bracts that are as long as the leaf blades and very similar in appearance. These bracts ascend slightly upward at the base and are widely spreading; some of these bracts are longer than the inflorescence. Each floral spike is about 1–2" long and short-cylindrical in shape; it consists of 20-50 linear-flattened spikelets that extend perpendicularly from its central axis in all directions. This provides each spike with a bottlebrush appearance. Each greenish yellow spikelet is about 13-18 mm. (½–¾") in length and 1-2 mm. across, consisting of about 5-11 florets and their scales. These florets and their scales are arranged in 2 ranks along the length of each spikelet; they become less green and more straw-colored with maturity. Each scale is linear-lanceolate with a pointed tip and it is curved along the middle of its length, where a green midvein occurs; the length of each scale is 3.5–6 mm. Each floret has an ovary, 3 stigmas, and 3 anthers. The blooming period occurs during the summer or early fall. Pollination is by wind. Each floret is replaced by an oblongoid achene that is 1.2–2.0 mm. long and bluntly 3-angled. The root system consists of a corm-like swelling at the base of the plant, shallow fibrous roots, and spreading rhizomes. Vegetative colonies can develop from the rhizomes.

This is one of the larger Cyperus spp. (Flatsedges) in Illinois. Individual plants of Straw-Colored Flatsedge can become 3' in length or more, but this is unusual. More typically, individual plants are ¾–2' tall. The floral spikelets of Straw-Colored Flatsedge are green to yellowish green when they are immature (as revealed in the photograph above). In contrast, Cyperus esculentus (Yellow Nut Sedge) has immature spikelets that are pale to golden yellow. The floral scales of Straw-Colored Flatsedge are unusually long and slender (easily exceeding 3.5 mm. in length) and they are relatively few in number (about 5-11) per spikelet. Similar flatsedges have shorter floral scales (less than 3.5 mm. in length) and they are often (but not always) more numerous per spikelet (easily exceeding 12 or more). Straw-Colored Flatsedge is rather variable across its range, and some robust specimens may have measurements that exceed what has been described above. Another common name for this species is Umbrella Flatsedge.

Straw-Colored Flatsedge has been found in every county of Illinois and is common. Habitats include low areas along ponds and rivers, sloughs and prairie swales, seeps, sedge meadows, ditches along roads and railroads, fallow fields, and gardens. Straw-Colored Flatsedge prefers sunny seasonal wetlands with a history of disturbance, although it is also found in higher quality wetlands. Sometimes it becomes a weed in fields and gardens.

Cyperus praelongatus Steud.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cyperus strigosus var. robustior Kunth:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cyperus ferax Baker:
India (Asia)
Madagascar (Africa & Madagascar)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cyperus ferax Rich.:
Argentina (South America)
Bolivia (South America)
Canada (North America)
Mexico (Mesoamerica)
Peru (South America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cyperus strigosus L.:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Cyperus stenolepis Torr.:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Man., Ont., Que., Sask.; Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Herbs, perennial (often flowering first year), rhizomatous. Culms basally swollen and cormlike, trigonous, (1–)20–40(–90) cm × 1–6 mm, glabrous or few prickles subapically. Leaves flat, (10–)20–40 cm × 1–4(–8) mm, margins and midribs glabrous or scabridulous. Inflorescences: spikes 1–4, loosely ovoid to oblong-cylindric; (6–)10–28(–50) × 10–40 mm; rays sometimes absent, usually (1–)3–6(–8), 0.5–7(–25) cm; if absent, inflorescence a congested head; 2d order rays sometimes present, 1–4(–9) cm; rachis 8–18(–25) mm; bracts (3–)5–7(–10), ascending at 30–45°, cross ribs sometimes conspicuous, (1–)10–30(–45) cm × (1–)2–4(–12) mm; rachilla ± deciduous, wings 0.4–0.5 mm wide. Spikelets (5–)12–50, linear-lanceoloid, compressed, 5–30 × 0.6–0.9 mm; floral scales ± deciduous, 3–11, appressed, medially green, laterally stramineous to pale brown, 3–4-ribbed laterally, (1–)3-ribbed medially, oblong-obovate, 3.2–4.5(–6) × 1–1.8 mm, apex ± acute, overlapping lower 1/4–1/2 of next scale. Flowers: anthers 0.3–0.5 mm; styles 1–2 mm; stigmas 3–4 mm. Achenes purplish brown, ± stipitate, narrowly oblong, (1.5–)1.8–2.4 × 0.5–0.6 mm, apex apiculate, acute, surfaces puncticulate.

Cyperus hansenii Britton; C. stenolepis Torrey; C. strigosus var. hansenii (Britton) Kükenthal; C. strigosus var. stenolepis (Torrey) Kükenthal; Mariscus stenolepis (Torrey) C. B. Clarke; M. strigosus (Linnaeus) C. B. Clarke

Straw-Colored Flatsedge has been found in every county of Illinois and is common. Habitats include low areas along ponds and rivers, sloughs and prairie swales, seeps, sedge meadows, ditches along roads and railroads, fallow fields, and gardens. Straw-Colored Flatsedge prefers sunny seasonal wetlands with a history of disturbance, although it is also found in higher quality wetlands. Sometimes it becomes a weed in fields and gardens.

Pond shores, ditches, damp, disturbed soils, sometimes weeds of gardens or croplands; 0–1500m.

The caterpillars of the moth Glyphipterix impigritella bore into the stems and leaf bases of Cyperus spp. (Flatsedges). The value of Straw-Colored Flatsedge to vertebrate wildlife is less than Cyperus esculentus (Yellow Nut Sedge) because its root system lacks tubers. However, Green-Winged Teal, Canada Geese, Redwing Blackbirds, and Bobolinks eat the seeds or seedheads of this and other flatsedges; the geese also eat the foliage. Cattle eat the foliage of flatsedges without ill effects, but it is not regarded as high quality forage.

Fruiting summer.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 1
Specimens with Barcodes: 2
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

The preference is full sun and moist to wet conditions. This flatsedge readily adapts to soil that is muddy, sandy, or gravelly. The size of this flatsedge is highly variable, depending on the fertility of the soil and the age of individual plants.