OregonFlora: Cyperus hermaphroditus vs. Cyperus acuminatus

	Cyperus hermaphroditus	Cyperus acuminatus
		sharp-pointed flatsedge, short flatsedge
Habit		Plants annual, cespitose.
Culms		roundly trigonous; (10)20–30(45) cm × 0.4–1.2 mm.
Leaves		8–12(16) cm × 1–2(4) mm.
Inflorescences		clusters head-like, hemispheric, 7–12(15) mm wide; rays 1–3(5), 0.5–2 cm long; longest inflorescence bracts erect to ascending.
Spikes		(15)25–50(75); ovoid, compressed, 4–7 × 2–3 mm; floral scales 8–20(35); ovate-lanceolate, 1–2 × 1–1.4 mm; yellowish; yellowish green, or light reddish brown, with light brown or greenish brown mid-stripe, 2-keeled, subtly 1-ribbed; apex acute, mucronate; straight to curved outward, glabrous or sparsely scabridulous.
Flowers		anthers 0.5 mm; styles 0.8–1.1 mm; stigmas 0.5 mm.
Achenes		broadly ellipsoid, abruptly contracted to base, 0.8–1.1 × 0.3–0.4 mm long; stipe 0.1 mm long.

	Cyperus hermaphroditus	Cyperus acuminatus
Distribution	[BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion		Disturbed seasonal wetlands, usually in sandy soils. 0–500 m. Sisk, WV. CA, WA; east to NH, south to Mexico. Native. Cyperus acuminatus is most often confused with C. squarrosus, which has longer, more outcurved awns and more veins on the floral scales.
Source		Flora of Oregon, volume 1, page 234 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. aggregatus, C. bipartitus, C. difformis, C. eragrostis, C. erythrorhizos, C. esculentus, C. fuscus, C. niger, C. odoratus, C. schweinitzii, C. squarrosus, C. strigosus
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 acuminatus

sharp-pointed flatsedge, short flatsedge

Habit

Plants annual, cespitose.

Culms

roundly trigonous; (10)20–30(45) cm × 0.4–1.2 mm.

Leaves

8–12(16) cm × 1–2(4) mm.

Inflorescences

clusters head-like, hemispheric, 7–12(15) mm wide;

rays 1–3(5), 0.5–2 cm long; longest inflorescence bracts erect to ascending.

Spikes

(15)25–50(75); ovoid, compressed, 4–7 × 2–3 mm; floral scales 8–20(35); ovate-lanceolate, 1–2 × 1–1.4 mm; yellowish; yellowish green, or light reddish brown, with light brown or greenish brown mid-stripe, 2-keeled, subtly 1-ribbed;

apex acute, mucronate; straight to curved outward, glabrous or sparsely scabridulous.

Flowers

anthers 0.5 mm;

styles 0.8–1.1 mm;

stigmas 0.5 mm.

Achenes

broadly ellipsoid, abruptly contracted to base, 0.8–1.1 × 0.3–0.4 mm long;

stipe 0.1 mm long.