Description: This native perennial sedge forms a dense to loose tuft of culms with alternate leaves; there are both fertile and vegetative shoots. The culms are ¾–2½' long, light to medium green, glabrous, and sharply triangular in cross-section; the edges of each culm are rough underneath the inflorescence, otherwise they are smooth. Along each culm, there are about 2-3 alternate leaves and withered remnants of older leaves near the base. The ascending to widely spreading leaf blades are 5-10" long and up to 6 mm. across; they are light to medium green, glabrous, and channeled in the middle. The upper surface of each leaf blade is smooth, while the lower surface is rough. The leaf sheaths are light to medium green and glabrous; each sheath is concave at the mouth.
Each fertile culm terminates in an
inflorescence consisting of a single staminate spikelet at the apex and 2-3
pistillate spikelets below. The slender staminate spikelet soon becomes brown.
Along the side of this spikelet, there is a bristle-like bract up to 2" long.
Each pistillate spike is about ¾–1½" long and a little less
than ½" across; it is densely packed with widely spreading perigynia and
their scales. The pistillate spikelets are short-oblongoid in shape and light
green while immature; they have a spiky appearance because of the long beaks of
their perigynia. The pistillate spikelets have slender pedicels about
¼–¾" long; they usually droop from their pedicels. At the
base of each pistillate spikelet, there is a leafy bract about 3-5 mm. across
and 4-6" long. The inflated perigynia are 5-6 mm. long and about 2 mm. across;
they are ovoid-ellipsoid with long slender beaks and wedge-shaped bottoms. The
apex of each perigynium's beak has a pair of teeth less than 1 mm. long. The
outer surface of an immature perigynium is light green and glabrous; it has
several longitudinal veins (sometimes they are difficult to see). The
pistillate scales are 3-4 mm. long, oval-shaped at the bottom, and long-awned
at the apex; each scale has a green vein in the middle, otherwise it is
membranous. The blooming period occurs from late spring to mid-summer. Each
perigynium contains an achene about 1.5 mm. long that is obovoid, bluntly
3-angled, and glabrous. The root system is fibrous and
short-rhizomatous.
Cultivation: This sedge prefers full to partial sun,
wet to moist conditions, and soil that is reasonably fertile (including those
containing loam, sand, or rocky material). Temporary flooding is
tolerated.
Range & Habitat:
Porcupine Sedge is occasional in central and northern Illinois, while in
southern Illinois it is uncommon or absent (see
Distribution
Map). Habitats include wet prairies, swamps, grassy fens, sedge meadows,
calcareous seeps, edges of marshes (sandy & non-sandy), and ditches. This
species is often found in wetlands that are calcareous.
Faunal Associations: A variety of insects feed on
Carex spp. (sedges), including Stethophyma spp. (Sedge
Grasshoppers), Plateumaris spp. (Leaf Beetles), and Cosmotettix
spp. (Leafhoppers). The caterpillars of several butterflies, skippers, and
moths feed on sedges (see Lepidoptera Table). Among vertebrate animals, the seeds
of sedges are an important source of food to many waterfowl, upland gamebirds,
and granivorous songbirds (see Bird Table).
Photographic
Location: Edge of a sandy marsh in Vermillion
County.
Comments: This is one of the
"bottlebrush" sedges of wetland habitats. Species in this group of sedges have
pistillate spikelets that are cylindrical and spiky in appearance; they can be
difficult to distinguish from each other. In particular, Porcupine Sedge
closely resembles Carex lurida (Sallow Sedge) and Carex comosa
(Bottlebrush Sedge). Sallow Sedge has larger perigynia (greater than 6 mm. in
length & 2.5 mm. in width) and shorter pedicels (less than ¼" long);
its pistillate spikelets don't droop from their pedicels to the same extent as
the pistillate spikelets of Porcupine Sedge. Bottlebrush Sedge differs in
having longer teeth at the upper tips of its perigynia (greater than 1 mm. in
length) and its achenes are ovoid in shape, rather than obovoid. Other similar
sedges in this group have pistillate scales that lack awns. Some authors refer
to Porcupine Sedge as Carex hystricina, but this is a misspelling of its
scientific name.