Vascular Plants of North Carolina
Account for Variable Flatsedge - Cyperus difformis   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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AuthorL.
DistributionTwo records are known for NC: Randolph County, NC Zoo, "edge of manmade wetland", Nell Allen in 2009; Dare County, "shore of Currituck Sound, 1 mile N of Duck", Usher & Tyndall in 1974.

Across much of the globe; in N.A. from NJ, PA, and KY, south to FL and TX; westward to OR and CA.
AbundanceRare.
Habitat"Edge of manmade wetland"; "shore of Currituck Sound".
PhenologyFlowering and fruiting August-October.
IdentificationVariable Flatsedge grows up to a foot tall, 1-15 flowering stems (culms) from a central point. Rounded heads terminate the culms. There are 12-20 floral scales per spikelet. There is only a single keel or ridge on the back of each scale (vs. 2 in some related species).
Taxonomic CommentsThe 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.
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State RankSE
Global RankGNR
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