Grasses

All true grasses (species in the grass family).

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Photo of several big bluestem seed heads against a blue sky.
The name “turkey foot” can help you identify native big bluestem: The seed heads resemble turkey feet.
Noppadol Paothong
Family

Poaceae (Graminae) (grasses)

Description

Grasses are annual or perennial plants with linear, parallel-veined, 2-ranked leaves whose lower portions sheath the stems (culms). The sheaths are often open (split) and have ligules (a membrane or group of hairs where the leaf blade joins the stem). Stems are round in cross-section, and hollow except at the nodes (joints where new leaves or branches arise). Flowers lack sepals and obvious petals; instead they are enclosed by scale-like glumes, lemmas, and paleas. Florets (individual flowers) are grouped into spikelets, which can grow in spikes, racemes, panicles, and other arrangements. Each fruit is a grain (caryopsis).

Similar species: Plants in the sedge family usually have 3-sided, solid stems, 3-ranked leaves, closed sheaths, flowers with scales at the base, and nutlike fruits (achenes). Plants in the rush family have round but solid stems, basal leaves, closed sheaths, flowers with similar-looking sepals and petals, and many-seeded capsules that are round in cross-section.

Size

Height: some species are only a few inches high, while others, such as big bluestem, corn, and bamboo, reach 8 feet or more.

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Photo of poverty grass clump amid fallen autumn leaves.
Poverty Grass (Curly Oat Grass)
You can recognize poverty grass by its short, curly basal leaves. It is common nearly statewide in dry, upland woods.

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Photo of Canada wild rye, with green but maturing seed heads.
Canada Wild Rye
The seed heads of Canada wild rye curve downward. This common native cool-season grass is also called nodding wild rye.

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Photo of river oats clump with dried seed heads and drying leaves.
River Oats
River oats is common nearly statewide in bottomlands, stream valleys, and other moist places.

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Photo of sideoats grama, closeup on floral spikes showing orange anthers.
Sideoats Grama (Flowers)
The floral spikes of sideoats grama all hang downward on one side of the stem. The anthers are often reddish orange.

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Photo of prairie showing big bluestem leaves and flowering stalks
Big Bluestem at Friendly Prairie
Big bluestem is the most famous of our native prairie grasses. The seed head of this tall grass branches into three parts, resembling a turkey’s foot.

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Photo of big bluestem young lower stalks
Big Bluestem Stems
Big bluestem's young flowering stalks and leaf sheaths typically have a bluish cast and are sometimes whitish-waxy (glaucous).

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Photo of Indian grass culm, held in a hand showing pointed auricle.
Indian Grass (Auricle)
Indian grass has a pair of stiff, pointed, clawlike auricles where the leaf blade attaches to the sheath.

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Photo of a big clump of Indian grass
Indian Grass Clump in Bloom
Indian grass is one of the tall grasses of the tallgrass prairie. Its flowering stems can reach 7 feet tall.

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Photo of eastern gama grass flowering plant
Eastern Gama Grass Flowering Plant
The fingerlike seed heads of eastern gama grass have separate male and female florets. The seed-bearing, female florets are in the lower portion of each spike.

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Photo of little bluestem seed heads looking fluffy in autumn
Little Bluestem Seed Heads in Autumn
The flower clusters of little bluestem are soft, usually somewhat curved, and 1–3 inches long; when mature they are tan or grayish white and fluffy.
Habitat and conservation

There are only about 10,000 species of grasses globally, but grasses cover a huge amount of landmass worldwide. They are the most widespread plant family. Many are weedy annuals and are some of the first plants to colonize barren landscapes. Some are invasive and threaten established native plant communities. Some have specific habitat requirements and are endangered. When humans started cultivating certain grasses and stayed near their farms, it was the beginning of cities and civilization.

iamge of Grasses Distribution Map
Distribution in Missouri

Statewide. Some species are fairly widespread and common. Others are rare or limited to certain habitats or parts of the state.

Status

Although the number of species in the grass family trails that of several other plant families, if you counted individual plants, grasses will easily win the numbers game. Grasses are by far the most economically important family of plants in the world. Grasses are the “staff of life” for almost every human; rice, corn, wheat, barley, oats, and rye are all grasses. Those can all be fermented into alcoholic beverages, too. Sugarcane, sorghum, and corn are made into sweeteners.

Life cycle

Grasses differ by life cycle and growth habit. Sod-forming grasses form new plants on horizontal stems much as strawberry plants do. They’re popular in lawns and pastures. Bunchgrasses form tufts or clumps, as new plants form right beside the parent plant. Cool-season grasses grow most efficiently in fairly cool, moist environments, usually blooming in spring, going dormant midsummer, and growing rapidly fall–winter. Warm-season grasses grow most and are greenest in bright, hot, dry months.

Human connections

In addition to feeding humanity, grasses are fodder for domestic animals. They provide materials for building shelters, tools, and more (think of bamboo chopsticks and fishing poles, thatching, mats, paper, insulation, and basketry). Turf and ornamental grasses are important, too.

Ecosystem connections

Grasses are the heart of grasslands, including Missouri’s tallgrass prairies. Multitudes of animals and plants live in grasslands worldwide. Grazing mammals need grasses. Grasses bind and protect soil, preventing erosion. The 1930s Dust Bowl occurred after grasses had been stripped from the land.