Description: This native perennial grass is
1-3' long and erect to sprawling. The branching culms are light green, terete,
and glabrous. Abundant alternate leaves occur along the length of each culm;
lower leaves tend to wither away. The leaf blades are up to 4" long and 5 mm.
across; they are dull grey-green and hairless. The blades are ascending to
widely spreading and either floppy or somewhat stiff. The leaf sheaths are dull
grey green, hairless, somewhat flattened (or keeled), and often coming loose
from the culms. At the junction of each blade and sheath, the ligule consists
of a papery truncate membrane about 1 mm. in length. The small nodes are
swollen and hairless. Each upper culm terminates in a narrow panicle of
spikelets up to 5" long and ½" across. Initially, this panicle has a
spike-like appearance, but it becomes a little more broad with age as its
secondary branches become less appressed against the central axis. These
secondary branches are up to 1½" long. The spikelets are densely
distributed along the secondary branches; they are light green or whitish
green, becoming light brown with age. Each spikelet is 6-8 mm. long, consisting
of a pair of awned glumes and a single lemma. The glumes are 6-8 mm. long
(including their awns), keeled-linear in shape, and mostly membranous, except
for their central veins and awns. The lemma is 3-4 mm. long, linear-lanceolate
in shape, and pale green; there is a tuft of fine hairs at its base. The tiny
anthers of each wind-pollinated floret are dull white and about 0.5 mm. long.
The blooming period occurs during the late summer and the grains of the
spikelets ripen during the fall. Disarticulation is above the glumes. Each
narrow grain is 1.5–2.0 mm. long. The root system is fibrous,
long-rhizomatous, and rather shallow. Loose colonies of plants are often formed
from the rhizomes.
Cultivation:
Generally, this grass prefers full or partial sun and a moist soil containing
loam, sandy loam, or silt. However, some local ecotypes of this species are
adapted to drier sites; the latter tend to have a more erect habit and stiffer
leaf blades.
Range & Habitat:
Marsh Muhly is occasional in the northern 3 tiers of counties and the western
half of Illinois, but it is uncommon or absent elsewhere in the state (see
Distribution
Map). Illinois lies toward the eastern range-limit of this species.
Habitats are highly variable; they include moist to dry-mesic prairies
(particularly in
disturbed areas), thin woodlands and savannas, low areas along rivers, roadside
ditches, and edges of marshes. Usually, these habitats are somewhat degraded
from a history of disturbance.
Faunal
Associations: The leafhoppers Flexamia imputans and
Plesiommata tripunctata feed on Muhlenbergia spp. in open
woodlands and other sheltered situations; sometimes Marsh Muhly occurs in these
kinds of habitats. The foliage is edible to cattle and other livestock while it
is young. Because this grass can form rather dense colonies, it can provide
significant cover for small mammals and other wildlife.
Photographic Location: The wildflower garden of the
webmaster in Urbana, Illinois.
Comments: Marsh Muhly is a rather ordinary-looking
grass that resembles Muhlenbergia frondosa (Common Satin Grass) and
several other species in this genus. It can be distinguished from them
primarily by its awned glumes, which are 6-8 mm. long. Other Muhlenbergia
spp. in Illinois have glumes that lack awns, although their lemmas are
sometimes awned. An exception is Muhlenbergia glomerata (Wild Timothy),
which has awned glumes of the same length as Marsh Muhly; these two species are
very difficult to distinguish. However, the anthers of Marsh Muhly are much
smaller (about 0.5 mm. in length) than those of Wild Timothy (about
1.0–1.5 mm. in length), while the papery ligules of Marsh Muhly are longer
(about 1.0 mm. in length) than those of Wild Timothy (about 0.5 mm. in length
or less). There have been some attempts to make generalizations about the
differing habitats that these two species are supposed to prefer, but this is
rather risky because fidelity to any particular habitat appears to be
low.