The grasslands of central North America are generally divided into three groups; the short-grass prairie of the West, the mixed-grass prairie of the Great Plains, and the tall-grass prairie which met the Eastern Forest somewhat east of the Mississippi River. The boundaries are and historically have been extremely fluid, responding to climate changes and creating much ground for dispute among experts!

The short grass prairie, often referred to as the Great Plains, is the rangeland of the West, with grasses such as Buffalo Grass (Buchloe dactyloides) and Blue Gamma Grass (Bouteloua gracilis) growing a few inches high.

The short-grass prairie is basically similar to the Russian steppe and could correctly be called a steppe. Characterized by low rainfall, exposed to winds and extreme temperatures, it is believed that there is simply insufficient moisture to support forest cover on the dry upland plains. The subsoil has a layer which is permanently dry. East of the short-grass prairie is the mixed-grass prairie, a transition area between the western rangelands and the Midwestern tall-grass prairie. The grasses there grow about two to four feet tall and include Little Bluestem (Andropegon scoparius), June Grass (Koeleria cristata), Needle Grass (Stipa spartea), and Western Wheatgrass (Agrophyron smighii), as well as a mix of tall-and short-grass prairie. In dry years, mid grasses like Little Bluestem die out and the short grasses take over. Over a few wet years, Little Bluestem will return. Since settlement, overgrazing has caused the mid-grasses to give way to short grasses. The area which defies simple explanation is the tall-grass, or true prairie. The word prairie is from the French word for meadow. The Midwestern TALLGRASS prairie, arguably some of the most fertile soil in the world, is now mostly gone, largely planted to fields of corn and soybeans. However, it is also losing an average of four tons of topsoil annually per acre. The Midwestern tall-grass prairie has its counterparts worldwide in the pampas of Argentina and the Black Earth Belt of Russia. The dominant species are Big Bluestem (Andropogon gerardi), Indian Grass (Sorghastrum nutans), and Switch Grass (Panicum vergatum).

One theory about the origin of the Tall-grass Prairie is that they developed after the retreat of the Wisconsin glacier, some 18,000 years ago. The climate then was apparently much drier then than now. Fossil records indicate that grasses were dominant after the glacier but not before, and grasses dominated since that event. Once a dense prairie sod is established, it is hard for other seedlings to compete. This was compounded by the drying effect of wind over open prairies making tree seedlings face a very harsh beginning. Once the parry became established, it is believed that it was maintained by grazing by buffalo and by fire, both naturally occurring and set by the native peoples. Often the rivers would create a boundary between prairie and forested lands; prairie dominating the Western banks of the river and forest beginning on the Eastern side, protected by the barrier of the river from the fires which swept across the plains. There is very little tall-grass prairie remaining, in small preserves and some old graveyards. The only significant area of unbroken prairie remaining is the Flint Hills region of eastern Kansas - four million acres that were too rocky to plow; one percent of the original tall-grass prairie.

INDIAN GRASS
Sorghastrum nutans
tall: 60 cm-2.7 m (2-9 ft.)
late summer: August-September

Sorghastrum nutans is a striking native perennial, one of the dominant species of the tall-grass prairie. During flowering, it is golden brown and shining, with the flowers slightly fuzzy and growing in small twisted bundles.

Indian Grass is easily confused with the introduced Tall Oats Grass (Arrhenatherum elatius), which is mainly visible in the spring, has no fuzz, and ranges in color from green to purple to silver, never tan.

BIG BLUESTEM
Andropogon gerardi tall: 75 cm - 1l7 m (2 ½ - 5 ft.)
grows in clumps
late summer: August - October

Like other Andorpogons, this species is constantly changing its color display. In flower, the inflorescence varies from bronze to a steely gray-blue; later the whole plant turns shades of red, brown, and purple. It's large, slightly fuzzy flower branches from the tops of the leafy stem, giving it the nickname of Turkey Claw or Beardgrass.

Andropogon gerardi was the dominant species of the tall-grass prairie. It is an excellent forage plant, and both domestic and wild grazing animals favor it over other species. Although most of its acreage has been plowed under, it still grows here and there in the Midwest and the East - in dry open places, along roadsides and shores, and in fields and prairies.

Big Bluestem was traditionally used for its diuretic and analgesic properties. The Chippewa used root decoction for stomachaches and gas. The Omaha used leaf tea as an external way to relieve fever and general debility.

SWITCH GRASS
Panicum virgatum Tall: up to 2.1 m (7 ft.)

This is another prevalent grass of the tall-grass prairie, its big leafy clumps found in moderately wet areas. Its flowers grow singly at the ends of the branches, the grain is hard and bony. It is purple in flower, and then tan. It is a sod-builder, a good forage species well liked by grazing animals both wild and domestic. In the East Switch Grass is often found in dryer soils, along sandy roadsides and along the upland edge of salt marshes where it grows in bunches. The leafy clumps last through the winter, although dead, and the yellow-gold color shows up as a touch of brightness on the landscape on rainy days.

Sources:
Grasses, an Identification Guide By Lauren Brown
Sponsored by the Roger Tory Peterson Institute - Peterson Field Guide to Medicinal Plants
By Steven Foster and James A. Duke