Vascular Plants of North Carolina
Account for Eastern Narrowleaf Sedge - Carex amphibola   Steudel
Members of Cyperaceae:
Members of Carex with account distribution info or public map:
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Section 5 » Order Cyperales » Family Cyperaceae
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DistributionMountains, Piedmont, and in the Coastal Plain along nutrient rich, brownwater rivers. Disjunct to Nags Head Woods on the Outer Banks (collected in 1898). Absent from the Sandhills proper.

MA to MI and MO south to GA and TX.
AbundanceCommon to abundant in suitable habitat in Mountains and Piedmont, uncommon in Coastal Plain. Often co-occurs with Carex grayi, C. intumescens, C. squarrosa, C. typhina, C. tribuloides, and others, forming dominant areas of Carex. Field botanists would do well to learn this sedge, from which to compare similar-looking species.
HabitatNutrient-rich soil of brownwater floodplain forests and bottomlands, mostly under hardwoods. Also onto lower rich forested slopes.
PhenologyFlowering and fruiting late April-June.
IdentificationVery similar to C. corrugata, and both often have a transverse crease near the tip of the perigynium. Perigynia of C. amphibola are larger than those of corrugata (see Weakley [2018] for details).
Taxonomic CommentsCarex grisea (= C. amphibola var. turgida) has been reported from NC, but all specimens seen to date are nominate C. amphibola.

The genus Carex is the largest in North America, and among the largest in the world. In temperate and boreal regions, Carex is often the dominant or co-dominant ground layer in many habitats. Seeds (achenes) are valuable food for birds and small mammals, while foliage is used by birds and mammals to make nests and as food by mammals. Species of Carex often look vastly different from one another -- spikes erect vs. drooping, tiny inflorescence vs. whopping, culms leafy vs. naked, perigynia beaked vs. beakless, stems densely bunched vs. single, etc. The genus has been divided into many sections (or groups), based on shared characters; some taxonomists have suggested that these be different genera, but that proves unworkable (so far). All Carex share the feature of a perigynium (an outer covering) which completely surrounds the achene (seed). This covering may fit tightly or loosely (like a small bladder), depending on which group or species. Details of perigynia shape, ornamentation, presence and size of beak, number of striations (or veins) are all important ID features. In recent years Rob Naczi and colleagues have stressed the importance of arrangement of perigynia -- whether spiral (3+ ranks) or distichous (2-ranked) -- and have named a number of new species as well as split off some older synonyms. Therefore, RAB's (1968) key, excellent for its time, can only be used in a general way today. Members of some sections of Carex are difficult to key out (notably Ovales, Laxiflorae, Griseae); this is in part due to variation among individuals of a species, or failings of the key. FNA has drawings of most species and some species may be found in two or more places within a key, to acount for variability. New species to NC, and new to science(!), continue to be found in NC.
Other Common Name(s)Narrowleaf Sedge, Creek Sedge
State RankS4 [S5]
Global RankG5
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B.A. SorrieMesic floodplain of McLendon Creek, Triassic Basin, Apr 2015. MoorePhoto_natural
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