Vascular Plants of North Carolina
Account for Broad Looseflower Sedge - Carex laxiflora   Lamarck
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 and Piedmont; a few scattered sites in the lower Coastal Plain.

ME, southern Que., and WI south to SC and AL.
AbundanceFrequent in the Mountains and Piedmont; rare in the Coastal Plain, with collections for just 3 lower Coastal Plain counties.
HabitatMesic to moist hardwoods and pine-hardwood forests, upper parts of bottomlands. Tolerates fairly acidic to alkaline soils, and thus has a very wide array of habitats -- mostly in uplands.
PhenologyFlowering and fruiting May-June.
IdentificationThe Laxiflorae section requires care in identification. Carex laxiflora has loosely flowered female spikes, that is, perigynia are not crowded or do not overlap (much) with each other. By contrast, C. blanda and C. crebriflora have crowded perigynia. Carex leptonervia spikes vary from rather crowded to rather loose; it differs in having only 2-3 prominent veins on each perigynium. In NC, C. laxiflora appears most like C. striatula, but differs in its shorter perigynia (3.2-4.1 mm vs. 3.9-5.1 mm). Carex styloflexa and C. chapmanii have lowest spikes on elongate, arching or drooping stalks, whereas those of C. laxiflora are short and erect. See also the C. kraliana species account.
Taxonomic CommentsNone

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)None
State RankS4 [S5]
Global RankG5
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