Sideoats Grama

Bouteloua curtipendula

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Photo of sideoats grama, closeup on floral spikes showing orange anthers.
The floral spikes of sideoats grama all hang downward on one side of the stem. The anthers are often reddish orange.
Jim Rathert
Other Common Name
Side-Oats Grama; Grama Grass
Family

Poaceae (grasses)

Description

Sideoats grama is a native perennial clump-forming grass. The rootstalks are creeping rhizomes. The flowering stalks are 1–3 feet tall, mostly erect or somewhat arched toward the tip. The leaf blades are flat and reach about 1 foot long and about ¼ inch wide; the bases of the leaf blades have short hairs that are widely spaced along the margins. The 30–70 oatlike seed spikes hang uniformly on one side of the flowering stem, and when mature, each is shed intact as a unit, leaving the main axis naked. Flower heads develop July–September.

Similar species: Two other grama grasses (genus Bouteloua) occur in Missouri: hairy grama (B. gracilis) and blue grama (B. hirsuta). Both are much less common, with restricted distributions, plus they are shorter plants and have rather short, dense seed heads that resemble eyebrows or curved combs. Another native prairie grass, eastern gama grass (Tripsacum dactyloides), is not closely related to these but the common name is similar. It is a larger grass whose dense flower spikes are long and fingerlike, with 1–4 spikes arising from the same point at the tip of the flowering stalk. Its separate male and female florets are on the same spike, but with the female (seed-bearing) florets in the lower third and the male (pollen-producing) florets above.

Size

Height: flowering stems 1–3 feet

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Photo of sideoats grama plant in a field
Sideoats Grama
Sideoats grama is a native perennial clump-forming grass with flowering stalks 1–3 feet tall. The oatlike seeds dangle uniformly in two rows on one side of the flattened stalk.

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Photo of a mature flowering stalk of sideoats grama
Sideoats Grama Mature Stalk
The 30–70 oatlike seed spikes of sideoats grama hang uniformly on one side of the flowering stem. When mature, each will be shed intact as a unit, leaving the main stalk naked.
Habitat and conservation

Occurs in glades, upland prairies, savannas, and rocky openings of mesic to dry upland forests, almost always on calcareous substrates (such as limestone or dolomite bedrock); also occurs on roadsides and railroads. Like most other prominent grasses of our native tallgrass prairies (such as big bluestem), sideoats grama is a warm-season grass that photosynthesizes most efficiently during the hottest part of the summer, a time when cool-season grasses may go dormant.

Distribution in Missouri

Scattered to common nearly statewide, but it does not occur in the Mississippi Lowlands of the Bootheel.

Status

The curious word “grama” came to America from Spanish speakers. The word comes from the Latin gramina, which means “grasses.” Therefore “grama grass” is a redundant expression, basically meaning “grass grass.” For a long time, the grass family was called the Gramineae, using the same Latin root. Botanists moved away from this and other descriptive family names when they decided that all plant family names should be based on the name of a representative genus (that’s why the grass family is now the Poaceae, after genus Poa). You might occasionally see the word “graminoid,” which means “grasslike,” used for plants like sedges and rushes, which are grasslike but not in the grass family.

Human connections

The unusual and attractive flowering stalks of sideoats grama makes it an intriguing ornamental grass for landscaping — and they’re native, too. Sideoats grama tolerates a wide range of growing conditions, including drought and rocky soils, and it looks good in dried flower arrangements. This species can also be used as a native turf grass, if it is regularly mowed only to about 2 to 4 inches.

Livestock producers value the high-quality, nutritious forage sideoats grama provides for cattle and other livestock. Its seed can be harvested and planted in pure or mixed plantings.

Ecosystem connections

Several birds are known to eat the seeds of this grass, and native herbivorous mammals, including bison, deer, and elk graze on the foliage. Several types of insects, especially leafhoppers and grasshoppers, eat the foliage of this species, too.