Description: This native perennial plant is about 1½–3' long with its stems erect or ascending. It often forms loose tufts of culms and leaves; many of these shoots are vegetative and don't produce spikelets of flowers. The culms are light green, hairless, and 3-angled, while the alternate leaves are up to ¼" across and 16" long. About 6-10 leaves are produced per culm; these leaves are evenly spaced along the culm beneath the stalk of the inflorescence, if there is any; for vegetative shoots, these leaves are produced to the apex of the culm. Like the culms, the leaves are light green and hairless; they are also linear in shape and slightly rough along the margins.
Fertile shoots produce a raceme of about
6-12 spikelets up to 2½" long. These spikelets are neither densely
clustered together nor remote from each other. Staminate flowers often occur at
the base of each spikelet, while the pistillate flowers are located above. Each
spikelet is about 1/3" long and ovoid in shape, consisting primarily of a dense
cluster of female flowers and their perigynia; it is rather conical at the
bottom, but more rounded at the top. Each perigynium is about 3–5 mm.
long, 1.2–1.8 mm. across, and flattened; it is ovate-lanceolate with a
slender beak at its apex, while its bottom is slightly wedge-shaped. The upper
half of the perigynium has a winged margin. The pistillate scale underneath
each perigynium is smaller in size and lanceolate in shape; it has a green
central vein and translucent margins (although it later becomes light brown).
The perigynia are initially light green, but they later become light brown as
the achenes mature. At the base of the lowest spikelet, there is slender green
bract that is ½" in length or longer; the second lowest spikelet may
have a conspicuous bract as well. The blooming period usually occurs during
early to mid-summer, although some plants bloom later. The brown achenes are
about 1.5 mm. in length, broadly oblongoid, and flattened; each achene also has
a small beak at both its top and bottom. The root system consists of rhizomes
and fibrous roots. Colonies of plants are often formed.
Cultivation: The preference is full sun to light
shade and wet to moist conditions. Various kinds of soil are tolerated,
including those that are gravelly, sandy, peaty, and loamy.
Range & Habitat: Blunt Broom Sedge is common in
southern Illinois and occasional to locally common in other areas of the state
(see
Distribution
Map). Habitats include wet woodlands, areas adjacent to semi-shaded vernal
pools, moist meadows in wooded areas or along rivers, powerline clearances in
wooded areas, wet prairies (including sand & dolomite prairies), marshes,
swamps, bogs, gravelly seeps, edges of ponds and lakes, and ditches. This sedge
occurs in a greater variety of habitats than most others.
Faunal
Associations: The flowers are wind-pollinated and don't attract many
insects. The caterpillars of various butterflies, skippers, and moths feed on
Carex spp. (see Lepidoptera Table). Other insects feeding on Carex
spp. include Stethophyma lineata (Striped Sedge Grasshopper),
Stethophyma celata (Otte's Sedge Grasshopper), and various leafhoppers
(particularly Cosmotettix spp.). The seeds of Carex spp. are a
significant source of food for various upland gamebirds, waterfowl, and
songbirds (see Bird
Table).
Photographic Location: A
moist meadow underneath a powerline clearance at Busey Woods in Urbana,
Illinois.
Comments: Blunt Broom
Sedge is a member of the Ovales Section of Carex spp. (Sedges); it is
notoriously difficult to distinguish these sedges from each other. These sedges
have slender leaves, racemes of small ovoid spikelets, pistillate flowers with
2 stigmas, and similar achenes; they differ primarily in the distribution of
their spikelets (widely separated, clustered together, or intermediate), the
shape of these spikelets (rounded or conical at one or both ends), and the size
and/or shape of their perigynia. Blunt Broom Sedge has spikelets that are
neither widely separated nor strongly clustered together, and they are more
rounded at the top than the bottom. The perigynia of Blunt Broom Sedge are at
least twice as long as across, winged along the upper half of their margins,
and rather wedge-shaped at the bottom (rather than rounded). This sedge also
produces more leaves per stem (6-10) than most others, and it also produces an
abundance of non-flowering shoots (leafy stems without spikelets). Some
authorities describe two varieties of Blunt Broom Sedge: the typical variety
has perigynia that are 3-5 times as long as they are wide, while var.
sangamonensis has perigynia that are 2-3 times as long as they are
wide.