Grass family (Poaceae)
Description: This native perennial grass is 3-7' tall and unbranched. It typically consists of tight bunches of flowering culms and their leaves. The culms are terete, glabrous, and light green to pale yellow. The blades of the alternate leaves are up to 2' long and ½" across; they are dull green to dark green, flat, and hairless. The blade of each leaf ascends upward from the culm and spreads outward towards its tip. The leaf sheaths are dull green, hairless, and open. The nodes of the culms are slightly swollen, dark-colored, and covered with fine silky hairs (at least when they are young). Most of the leaves are located along the lower halves of the culms. Each culm terminates in a narrow panicle of floral spikelets. This panicle is up to 14" long and it has several ascending branchlets that are individually up to 4" long. The branchlets are some shade of golden brown or tan, mostly glabrous, and slender. However, the tips of the branchlets underneath the spikelets usually have fine silky hairs. Each branchlet terminates in a one-flowered spikelet about 1/4" (6 mm.) to 1/3" (8 mm.) long. This spikelet consists of a pair of appressed glumes and a pair of membranous lemmas within. The glumes are about the same length as the spikelet; they are golden brown to tan, lanceolate, gently curved, and somewhat shiny. One glume is covered with silky white hairs, while the other glume is mostly hairless. The fertile lemma has a long awn at its tip that is often bent, curly, or twisted; this awn is about ½" in length. At the base of each spikelet, there is an obsolescent pedicel up to ¼" long; this pedicel is covered with silky hairs and it lacks a spikelet at its apex. The floret of each spikelet has 3 stamens with yellow to brown anthers and 2 stigmas that are white and plumose. The blooming period occurs during late summer to early fall. At this time, the branchlets of the panicle spread outward slightly; afterwards, they become more appressed and ascending. The root system is fibrous and has short rhizomes.
Cultivation: The preference is full to partial sun and slightly moist to dry conditions. Various kinds of soil are tolerated, including those that can loam, clay-loam, sand, and gravel. Most growth and development occurs during the warm weather of summer because of the C4 metabolism of this grass. It can spread aggressively in some situations (e.g., prairie restorations).
Range & Habitat: This common grass can be found in every county of Illinois (see Distribution Map). It was one of the dominant grasses of the prairies that covered much of Illinois during historical times. Habitats include savannas and sandy savannas, black soil prairies, clay prairies, sand prairies, gravel prairies, dolomite prairies, hill prairies, cemetery prairies, barrens with scrubby vegetation, limestone glades, grassy fens, fallow fields, roadsides, and areas along railroads (particularly where prairie remnants occur). Indian Grass is often used in tallgrass prairie restorations.
Faunal Associations: Several species of grasshoppers feed on the foliage of Indian Grass (see Grasshopper Table); these grasshoppers are an important source of food to many insectivorous songbirds and upland gamebirds. Other insects that feed on this prairie grass include the leafhopper Flexamia reflexus, the planthopper Myndus fulvus, the Issid planthopper Bruchomorpha extensa, and the caterpillars of Amblyscirtes hegon (Pepper-and-Salt Skipper). The foliage is also palatable to hoofed mammalian herbivores, including bison and cattle. Because of its height and tendency to remain erect, it provides good cover for many kinds of birds and animals in prairies.
Photographic Location: A restored prairie at Meadowbrook Park in Urbana, Illinois. In the upper photograph, Andropogon gerardii (Big Bluestem) is the tall grass in the background.
Comments: This tall prairie grass is attractive, particularly while the florets are blooming. It remains erect throughout the summer and even during the winter. Another dominant prairie grass, Andropogon gerardii (Big Bluestem), is more likely to lean in the direction of the prevailing winds, and its culms topple over during the winter to smother surrounding vegetation. Indian Grass is easy to identify because of its height and distinctive golden-colored inflorescence. It is distantly related to Sorghum spp. (Sorghums) of the Old World, including the introduced Sorghum halepense (Johnson Grass). However, the spikelets of Sorghums occur in pairs (one sessile, the other pedicellate). Indian Grass and other Sorghastrum spp. have pairs of sessile spikelets and empty pedicels; these pedicels lack spikelets. Other Sorghastrum spp., which occur primarily in the southeastern states, have spikelets with awns at least ¾" long. In contrast, Indian Grass has awns that are less than ¾" long.