Description: This native perennial plant is about 3-7'
tall and usually unbranched; it forms a tuft of leaves and culms. These culms
are light green to pale reddish green, hairless, and round in circumference.
The alternate leaves are up to 2½' long and 1½" across, becoming
smaller as they ascend the stalk; they are light green to green, linear, and
hairless. The leaves typically arch upward near the stalk and downward toward
their tips; the larger leaves often have a white central vein that is rather
conspicuous. The culm terminates in 1-3 spikes of flowers; each spike is
narrowly cylindrical and up to 1' long. Spikelets of male flowers occur along
the upper two-thirds of each spike, while spikelets of female flowers occur
along the bottom third. The male flowers have lanceolate green scales (lemmas)
about 1/3" in length; they occur as pairs in each short spikelet. Each male
flower has 3 stamens consisting of slender white filaments and large orange
anthers. The female flowers are sunken into the central axis (rachis) of the
spike; each female flower has a hard outer scale to protect the developing
grain and it produces 2 feathery styles that are pale purple or purplish pink.
The blooming period occurs during the summer. Each female flower produces a
single large seed with a hard coat. The root system consists of fibrous roots
and rhizomes. Vegetative clumps of plants are often formed.
Cultivation: The preference is full to partial sun,
moist to mesic conditions, and a fertile loam or clay-loam to sustain its
robust growth. This species of grass can become large, although it is not
particularly aggressive. The seeds require moist stratification (exposure to
moisture & cool temperatures) in order to germinate; it is easier to
propagate new plants by dividing the clumps.
Range & Habitat: Gama Grass occurs occasionally
in the southern half of Illinois; it is absent from northern Illinois (see
Distribution
Map). Illinois lies along the northern edge of the range for this species.
Habitats include moist to mesic prairies, prairie swales, thickets, woodland
borders, savannas, limestone
glades, abandoned fields, and areas along
railroads and roadsides. Sometimes this grass can be observed in drier areas
that are rocky or gravelly. At one time, large colonies of Gama Grass occurred
in the moist prairies of Illinois and many southern states, but it has since
declined in abundance.
Faunal
Associations: The flowers are wind-pollinated and attract few
insects. The caterpillars of Problema byssus (Byssus Skipper) feed on
the foliage of Gama Grass. The nutritious foliage is readily eaten by
livestock. Probably bison, elk, and other large herbivores grazed on the
foliage before they were extirpated within the state.
Photographic Location: A restored prairie at
Meadowbrook Park in Urbana, Illinois.
Comments: Gama Grass is an interesting plant with an
unusual appearance that has some similarities to Zea mays (Cultivated
Corn). While Gama Grass is a distant relative of Cultivated Corn, hybrids
between these two species are unknown. Both of these species resemble each
other as follows: 1) they are large-sized grasses, 2) their larger leaves have
white midveins, 3) their sessile flowers occur in spikes, and 4) male and
female flowers occur in separate locations (monoecious). However, the male and
female flowers of Gama Grass occur in different locations of the same terminal
spikes, while the male and female flowers of Cultivated Corn occur on separate
spikes. While Cultivated Corn is a summer annual, Gama Grass is a perennial.
They are both members of a tribe of Grasses that occurs mainly in subtropical
or tropical America.