OregonFlora: Cyperus hermaphroditus vs. Cyperus strigosus

	Cyperus hermaphroditus	Cyperus strigosus
		false nutsedge
Habit		Plants perennial, often flowering first year, rhizomatous.
Culms		basally swollen and corm-like, trigonous; (1)20–40(90) cm × 1–6 mm.
Leaves		(10)20–40 cm × 1–4(8) mm.
Inflorescences		clusters loosely cylindric, 1–4; (6)10–28(50) × 10–40 mm; rays (0)3–6(8), 0.5–7(25) cm; inflorescence bracts ascending at 30–45°.
Spikes		(5)12–50, linear-lanceoloid, compressed, 5–30 × 0.6–0.9 mm; rachilla more or less deciduous; wings 0.4–0.5 mm wide; floral scales more or less deciduous, 3–11, appressed, oblong-obovate, 3.2–4.5(6) × 1–1.8 mm, stramineous to pale brown with green mid-stripe; lateral ribs 3–4; medial ribs (1)3; apex more or less acute, overlapping lower 25–50% of next scale.
Flowers		anthers 0.3–0.5 mm; styles 1–2 mm; stigmas 3–4 mm.
Achenes		more or less stipitate, narrowly oblong; (1.5)1.8–2.4 × 0.5–0.6 mm.

	Cyperus hermaphroditus	Cyperus strigosus
Distribution	[BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion		Lake shores and river margins exposed as water level falls, ditches, other disturbed wet soils, sometimes a weed in croplands. 0–600 m. BW, Col, CR, Sisk, WV. CA, ID, NV, WA; north to Saskatchewan, east to ME and FL. Native. Cyperus strigosus is common in Oregon. Individuals that flower the first year are easily confused with C. erythrorhizos, C. esculentus, and C. odoratus. Cyperus erythrorhizos has shorter floral scales; C. esculentus has persistent floral scales; C. odoratus has subcylindric spikes.
Source		Flora of Oregon, volume 1, page 237 Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa	C. acuminatus, C. aggregatus, C. bipartitus, C. difformis, C. eragrostis, C. erythrorhizos, C. esculentus, C. fuscus, C. niger, C. odoratus, C. schweinitzii, C. squarrosus, C. strigosus	C. acuminatus, C. aggregatus, C. bipartitus, C. difformis, C. eragrostis, C. erythrorhizos, C. esculentus, C. fuscus, C. niger, C. odoratus, C. schweinitzii, C. squarrosus
Web links	Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cyperus hermaphroditus

Cyperus strigosus

false nutsedge

Habit

Plants perennial, often flowering first year, rhizomatous.

Culms

basally swollen and corm-like, trigonous; (1)20–40(90) cm × 1–6 mm.

Leaves

(10)20–40 cm × 1–4(8) mm.

Inflorescences

clusters loosely cylindric, 1–4; (6)10–28(50) × 10–40 mm;

rays (0)3–6(8), 0.5–7(25) cm;

inflorescence bracts ascending at 30–45°.

Spikes

(5)12–50, linear-lanceoloid, compressed, 5–30 × 0.6–0.9 mm;

rachilla more or less deciduous;

wings 0.4–0.5 mm wide; floral scales more or less deciduous, 3–11, appressed, oblong-obovate, 3.2–4.5(6) × 1–1.8 mm, stramineous to pale brown with green mid-stripe;

lateral ribs 3–4; medial ribs (1)3;

apex more or less acute, overlapping lower 25–50% of next scale.

Flowers

anthers 0.3–0.5 mm;

styles 1–2 mm;

stigmas 3–4 mm.

Achenes

more or less stipitate, narrowly oblong; (1.5)1.8–2.4 × 0.5–0.6 mm.

Cyperus hermaphroditus

Cyperus strigosus

Distribution

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Lake shores and river margins exposed as water level falls, ditches, other disturbed wet soils, sometimes a weed in croplands. 0–600 m. BW, Col, CR, Sisk, WV. CA, ID, NV, WA; north to Saskatchewan, east to ME and FL. Native.

Cyperus strigosus is common in Oregon. Individuals that flower the first year are easily confused with C. erythrorhizos, C. esculentus, and C. odoratus. Cyperus erythrorhizos has shorter floral scales; C. esculentus has persistent floral scales; C. odoratus has subcylindric spikes.