Vascular Plants of North Carolina
Account for Yellow Flatsedge - Cyperus flavescens   L.
Members of Cyperaceae:
Members of Cyperus with account distribution info or public map:
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Section 5 » Order Cyperales » Family Cyperaceae
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DistributionPrimarily in the Mountains and Piedmont; outer Coastal Plain (with a broad gap in the middle and western Coastal Plain).

Pantropical, north to MA, southern Ont., MI, MO, and KS.
AbundanceFrequent in the Mountains and Piedmont; uncommon in the outer Coastal Plain; rare in the western and central Coastal Plain and Sandhills. With collection records for nearly 60 counties, the species is certainly worthy of an S5 State Rank.
HabitatMoist to wet soils of marshes, margins of impoundments, river shores, ditches, disturbed areas; generally in the open.
PhenologyFlowering and fruiting July-September.
IdentificationThis species is visually quite similar to C. polystachyos, C. filicinus, and C. bipartitus, but it differs in its black mature seeds (vs. brown or gray). It is also similar to C. compressus, but the seeds are lens-shaped (lenticular) in cross-section (vs. definitely 3-angled).
Taxonomic CommentsIncludes var. poiformis.

The genus Cyperus is mostly tropical and warm-temperate in distribution; thus, in NC it is much commoner in the Coastal Plain than in the Mountains and Piedmont. Most species have 1-few flowering stems (culms) from grasslike basal leaves, plus a few stem leaves. At the summit is an inflorescence of very open and branched, or tightly packed, spikes, varying among species from brown to golden brown to straw-color to reddish. The arrangement of the spikelets is important, whether like a hand (digitate) or in paired rows (pinnate); as is the shape of the achene (seed), whether bi-convex in cross-section or triangular. As a group, Cyperus tends to be weedy and readily enters disturbed ground; this is true for many natives as well as all the aliens. In recent years, following DNA research, the genus has incorporated several genera that in RAB (1968) or other manuals were separate: Hemicarpha, Lipocarpha, and Kyllinga.
Other Common Name(s)None
State RankS4 [S5]
Global RankG5
State Status
US Status
USACE-agcpOBL link
USACE-empOBL link
County Map - click on a county to view source of record.
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B.A. SorrieSandhills Game Land, shore of Broadacres Lake, Aug 2014. RichmondPhoto_natural
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