Description: This native perennial grass is about 2–2½' long, forming short branches along the central culm. This grass usually sprawls across the ground or neighboring vegetation, although it is sometimes erect. The central culm is slender, terete, smooth-textured, and glabrous; it is initially light green (sometimes with reddish tints), but later becomes light tan. Up to 12 leaves alternate along the central culm. The leaf blades are up to 3" (8 cm.) long and ¼" (6 mm.) across; they are medium green, broadest near the middle, and hairless. The leaf sheaths are light to medium green and hairless, covering most of the culm. Both the blades and sheaths are rather dull-looking, rather than shiny. The short ligules are light tan, stiff, and hairless, while the nodes are short, swollen, and glabrous.
The central culm terminates in a narrow
panicle of spikelets up to 3½" long and ¾" across. This panicle
consists of about 6-12 appressed to ascending branchlets; each branchlet is up
to ¾" long. Axillary panicles also develop from the middle to upper
leaves on short branches; these axillary panicles are smaller than the terminal
panicle, otherwise they are similar in appearance. While the flowers are
blooming, these panicles of spikelets spread to their maximum extent (about
¾" across), becoming broadest toward the middle. At this time, they are
shiny light green (sometimes with pale purplish tints). After the flowers have
bloomed, the panicles contract their branches, becoming more narrow, and they
change in color to light tan. Each spikelet consists of a pair of narrowly
lanceolate glumes (about 2 mm. long) and a single fertile lemma (about
2–2.5 mm. long). There are 3 anthers and the plumose stigmas are pale
purple. The blooming period occurs during late summer into the fall. Each
spikelet can develop a single grain that is tiny and narrow. The root system is
fibrous and rhizomatous. This grass often forms vegetative
colonies.
Cultivation: The
preference is light shade to full sun, moist to mesic conditions, and a fertile
loamy soil, although other kinds of soil are tolerated. Sometimes this grass
can spread to places where it isn't wanted, but there are more aggressive grass
species than this. It is rather slow to develop and doesn't become conspicuous
until later in the year.
Range &
Habitat: Common Satin Grass is common in most areas of Illinois,
although its distribution is more spotty in some central and south central
areas of the state. Habitats include openings in moist woodlands, bluffs and
the base of wooded slopes, moist depressions of cliffs, prairie swales, low
areas along rivers and ponds, drainage ditches, fence rows, fields, edges of
back alleys, and areas along railroads and roadsides. This grass is typically
found in disturbed areas that are partially shaded. It has low fidelity to any
particular habitat.
Faunal
Associations: The flowers are wind-pollinated and attract few
insects. The plant bug Stenodema vicinum reportedly feeds on
Muhlenbergia spp. (Satin Grasses). The seeds of Common Satin Grass are
too tiny to be of any interest to birds; cattle and probably other hoofed
herbivores readily eat the young foliage. Because this grass often grows in
dense colonies, it provides cover for small rodents and other
wildlife.
Photographic Location: A
low moist area along a drainage ditch in Savoy, Illinois.
Comments:
This grass is often encountered in areas that are overgrown and weedy, although
few people recognize it. Only the inflorescence has a satiny appearance, and
that lasts only a short period of time. Common Satin Grass was once regarded as
another variety of Muhlenbergia neomexicana (Leafy Satin Grass),
although they are now considered separate species. Because Common Satin Grass
and Leafy Satin Grass are very similar in appearance, they are difficult to
distinguish. However, the culms of Common Satin Grass are glabrous and
smooth-textured, while the culms of Leafy Satin Grass are more rough and
sometimes covered with short fine hairs. Leafy Satin Grass tends to be more
erect and less branched than Common Satin Grass, but such distinctions aren't
always reliable. Many other Muhlenbergia spp. (Satin Grasses) have
panicles of spikelets that are even more narrow (up to ¼" across) than
those of Common Satin Grass and Leafy Satin Grass. Another species,
Muhlenbergia racemosa (Wild Timothy), has panicles that are just as
broad (up to ¾" across), but its glumes are much longer (4-8 mm.). There
is a rare form of Common Satin Grass, f. commutata, that has awned
lemmas.