This perennial sedge forms a small tuft of leafy culms about 1¼-2½'
tall. The culms are light to medium green, 3-angled, glabrous,
and unbranched; they are slightly rough along their margins toward
their apices. About 4-8 alternate leaves occur along the entire
length of each culm; their blades are ascending to widely spreading.
Leaf blades are up to 13" long and 6 mm. across; they are medium to
dark green, glabrous, and slightly rough along their margins. Leaf
sheaths are medium green, glabrous, and longitudinally veined
along their outer sides (2 sides of each sheath), and they are
white-membranous along their inner sides (1 side of each sheath). The
ligules are V-shaped and short-membranous.
Each fertile culm terminates
in an inflorescence consisting of a single terminal spike on a short
erect peduncle and a leafy bract at the base of the peduncle.
Alternatively, an inflorescence may have 2-3 spikes in an
inflorescence, but this is highly unusual. The main body of the spike
is ¾-1½" long, ½-¾" across, and broadly cylindrical in shape.
All around this portion of the spike, 80 or more perigynia are packed
densely together; the beaks of the perigynia point upward at the top of
the spike, they point outward toward the middle of the spike, and they
point downward at the bottom of the spike. The bodies of the perigynia
are 4-5 mm. in length and 2-3 mm. across, while their narrow beaks are
2.5-3.0 mm. long. The bodies of the perigynia are oblanceolate to
obovoid in shape, slightly compressed (flattened), glabrous, and
longitudinally veined (the veins are usually obscure). The pistillate
scales are 3-4 mm. in length, 1 mm. across., narrowly lanceolate to
narrowly oblanceolate, tapering to acute tips; they are green-veined in
the middle and membranous along their margins. In contrast to the main
body of the spike, the bottom of each spike is
very narrow; this is
where the staminate florets and their scales occur. The peduncle of the
terminal spike is about 1½" long. If lateral spikes occur, they are
usually the same size or a little smaller than the terminal spike, and
they lack staminate florets. The leafy bract at the base of each
inflorescence is up to 6" long and 3 mm. across. The blooming period
occurs from late spring to mid-summer for about 1-2 weeks. The florets
are cross-pollinated by the wind. The achenes are 2.5-3.5 mm. long,
bluntly 3-angled, ellipsoid in shape, and glabrous. Because of the
inflated perigynia, the achenes can be distributed primarily by water.
The root system is short-rhizomatous and fibrous.
This sedge adapts to light shade or partial sun,
wet to moist conditions, and soil containing loam, silt, sand, or
gravel. Shallow standing water is tolerated if it is seasonal and
temporary, rather than permanent.
Squarrose Sedge is fairly common in
Illinois, while in central and northern Illinois it is uncommon.
Habitats include wet areas of bottomland woodlands,
prairie swales, swamps, sedge meadows, and gravelly seeps. This sedge
usually occurs in shaded or partially shaded areas of wetlands. Less
often, it can be found in wet sunny areas.
) are ubiquitous in wetland
areas and many insects are adapted to feed on them in these habitats.
These species include leaf beetles (primarily Plateumaris spp.
(Sedge Billbug), seed bugs (Lygaeidae), plant
bugs (Miridae), the shield bug Eurygaster
, aphids and
leafhoppers, stem-boring larvae of flies, caterpillars
of moths and skippers, caterpillars of the butterflies Satyrodes eurydice
(Eyed Brown) and Satyrodes
(Appalachian Brown), and sedge grasshoppers (Stethophyma spp.
The Insect Table
of these species. Some vertebrate animals also use wetland sedges as a
source of food. Ducks, rails, and other wetland birds feed on the seeds
or spikelets (see Bird Table
such turtles as Chelydra
(Snapping Turtle) and Kinosternum subrubrum
Turtle) feed on the spikelets or foliage (Ernst et al., 1994). Among
mammals, muskrats eat the culms, roots, or sprouts of wetland sedges
occasionally, while such mammals as the White-Tailed Deer
and Black Bear feed on the foliage or spikelets very sparingly.
A sandy swamp at the Indiana Dunes State Park in
Many wetland sedges (Carex spp.
large spikelets with
inflated perigynia. While almost all of these sedges have 2 or more
spikelets per inflorescence, Squarrose Sedge is highly unusual in
having only a single terminal spike in its inflorescence (for this
species, 2-3 spikelets can occur in an inflorescence, but this happens
rarely). The only other sedge in Illinois that closely resembles it,
Cattail Sedge (Carex
), often produces 2-4 spikelets
per inflorescence, instead of a single terminal spike. The terminal
spike or spikelet of Cattail Sedge has staminate florets
and scales at its bottom and sometimes at its apex. In
contrast, the terminal spike of Squarrose Sedge never produces
staminate florets and scales at its apex. In addition, Cattail Sedge
differs from Squarrose Sedge in the following characteristics: 1) its
blades are more wide (up to 10 mm. across), 2) the beaks of the lower
perigynia of its spikelets usually point outward rather than
downward, and 3) its achenes are shorter
(2.0-2.5 mm. in length) and less elongated in shape. Another species
that is somewhat similar, Carex
(Frank's Sedge), produces
multiple spikelets per inflorescence and its pistillate scales are much
longer (up to 10 mm. in length) and more conspicuous.