Golden
Sedge
Carex aurea
Sedge family (Cyperaceae)
Description:
This perennial sedge forms a loose
tuft of leafy culms about 4-18"
tall. The culms are light green, 3-angled, glabrous, and stiff. The
alternate leaves occur mostly along the lower half of each culm; their
blades are ascending to widely arching. The leaf blades are 4-12" long
and 1.5-4.0 mm. across; they are light green, glabrous, and
longitudinally furrowed. The leaf sheaths are light green to
membranous, glabrous, and relatively tight. Each fertile culm
terminates in an inflorescence consisting of a terminal staminate
(male) spikelet and 2-4 pistillate (female) spikelets. However,
sometimes the staminate spikelet is absent, particularly on shorter
culms. On rare occasions, the terminal spikelet may be gynecandrous
with a few perigynia above the staminate florets. The narrow staminate
spikelet is up to ½" (12 mm.) long; it soon turns brown after
flowering. The staminate spikelet is either sessile or it has a short
peduncle. The pistillate spikelets are ¼–¾" (6-20 mm.) long and
cylindrical in shape; each of these spikelets has 4-16 perigynia and
their scales. On a typical pistillate spikelet, the perigynia are more
crowded toward its apex than toward its bottom.
The perigynia are
2.5-3.0 mm. long and about 2.0 mm. across; they are obovoid in shape
and glabrous. The perigynia are beakless toward their tops and
stipe-like toward their bottoms; along their sides they have faint
longitudinal veins. Immature perigynia are pale green, while mature
perigynia are golden yellow or orange. However, mature perigynia
persist on their spikelets for only a short period of time. The
pistillate scales are about 2.0 mm. long and ovate in shape; their tips
are usually acute to cuspidate (appearing short-awned). Initially,
these scales have green central veins and membranous margins, but they
soon become brownish and sometimes detach from their spikelets before
the perigynia are mature. The pistillate spikelets have short stiff
peduncles; they are normally erect to ascending. Leafy bracts occur at
the bases of these spikelets. The lower bracts are rather large and
usually overtop the inflorescence, while the upper bracts are
significantly shorter. These bracts are similar in appearance to the
leaves. The blooming period occurs during late spring, lasting about
1-2 weeks. The florets are cross-pollinated by the wind. Afterwards,
the mature perigynia become detached from their spikelets; each
perigynium contains a single achene. The achenes are about 1.5 mm. long
and a little less across; they are broadly lenticular (lentil-like) in
shape and somewhat flattened. The root system is fibrous and
short-rhizomatous.
Cultivation:
The preference is full or
partial sun, wet to moist conditions, rocky or sandy soil that is
calcareous, and cool temperatures. This sedge dislikes hot weather and
does not compete well with taller ground vegetation on fertile loam.
Most growth and development occurs during the spring and early summer.
Range
& Habitat: The native Golden Sedge (Carex aurea) is
found primarily in NE
Illinois, where it is rare (see Distribution
Map). This sedge is
state-listed as 'endangered.' Illinois lies along its southern
range-limit. It is more common in Michigan and other areas further to
the north. Habitats include moist sand prairies and meadows, interdunal
swales, sandy fens, hillside seeps and springs, and shallow beach
pools. This sedge can be found in both disturbed and higher quality
habitats that are very sandy or rocky.
Faunal
Associations:
Various insects feed on the foliage, seeds,
and
plant juices of wetland sedges (Carex
spp.). These species include
several aquatic leaf beetles (primarily Plateumaris spp.),
the Sedge
Billbug (Sphenophorus
costicollis), sedge grasshoppers (Stethophyma
spp.), many aphids (Thripsaphis
spp. & others), several
leafhoppers (especially Cosmotettix
spp.), the spittlebug Philaenus
parallelus, the seed bugs Cymus angustatus and Oedancala dorsalis,
the
plant bugs Mimoceps
insignis and Teratocoris
discolor, larvae of the
flies Cordilura varipes
and Loxocera cylindrica,
caterpillars
of several skippers (Euphyes
spp., Poanes
spp., & others),
caterpillars of the butterfly Satyrodes
eurydice (Eyed Brown),
and caterpillars of such moths as the Virginia Ctenucha (Ctenucha virginica), the Tufted Sedge Moth (Hypocoenia inquinata),
and the American Ear Moth (Amphipoea americana). Among vertebrate
animals, the seeds and spikelets of wetland sedges are an important
source of food to many ducks, rails, and granivorous
songbirds. The Bird Table lists
many of these species. White-Tailed
Deer browse on sedges to a limited extent, while muskrats sometimes
feed on the roots and young shoots.
Photographic
Location:
The wildflower garden of the webmaster in
Urbana, Illinois.
Comments:
The most interesting thing about this sedge are the colorful perigynia
(golden yellow to orange) containing the seeds. Unfortunately, they
don't persist in this state for very long before falling to the ground.
Golden Sedge (Carex aurea)
closely resembles Garber's Sedge (Carex
garberi), which also occurs in NE Illinois. This latter
sedge can be
found along the beaches of Lake Michigan. Unlike Golden Sedge, the
mature perigynia of Garber's Sedge have a white-mealy appearance and
its terminal spikelets are usually gynecandrous (female florets and
their perigynia are held above the male florets). Otherwise, they are
quite similar to each other.