American slough grass (Beckmannia syzigachne)

American slough grass

Top facts

  • The American slough grass occurs across much of the United States and, despite its name, can also be found in some parts of Europe and Asia.
  • The American slough grass can be distinguished from other grass species by its distinctive inflorescences.
  • The seeds of American slough grass are eaten by waterfowl, seed eating birds, and small mammals.
  • The wetland habitat of the American slough grass is vulnerable to pollution, and to conversion for development.
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American slough grass fact file

American slough grass description

GenusBeckmannia (1)

The American slough grass (Beckmannia syzigachne) is a perennial annual grass with stout, leafy stems (2). The inflorescences are arranged in racemes known as ‘spikelets’, which are made up of several florets, each protected by several bracts. The double row and dense packing of the spikelets distinguishes the American slough grass from other grasses in the same type of habitat (2) (3). The seeds of this species are flat and disc-shaped (2).

Also known as
American sloughgrass, Beckmann’s grass, caterpillar grass, slough grass, western sloughgrass.
Beckmannia eruciformis, Panicum syzigachne.
Height: 60 - 100 cm (2)
Leaf length: up to 36 cm (3)
Leaf width: 3 - 10 mm (3)

American slough grass biology

The seeds of the American slough grass provide an important food source for waterfowl, seed-eating birds and small mammals (2). This species is often sown to enhance the amount wildlife in wetlands, and for erosion control along ditches, streams, waterways and shorelines (2). It also frequently colonises wetland soils that have been denuded due to grazing or tillage and it is considered to be an important species for the restoration of wetland habitats (2) (7).


American slough grass range

This wide-ranging species can be found across much of North America, from Alaska and California in the west to Quebec to Pennsylvania in the east (2) (4). The American slough grass can also be found in parts of Russia and in temperate areas in Asia, including certain parts of Mongolia, China, and Japan (2) (5) (6).


American slough grass habitat

The American slough grass can be found in a variety of wet habitats, including shorelines, stream banks, meadows, and pond or lake margins (2) (3) (4). This grass thrives in soils that are saturated with water throughout the year (2).


American slough grass status

The American slough grass has not yet been assessed by the IUCN.


American slough grass threats

There are not currently known to be any threats to the American slough grass, although all wetland species are threatened by habitat loss due to these environments being vulnerable to pollution and land conversion (8) (9). Since 1600, around half of the original wetlands in the United States have been drained and converted, equating to an area of around 445,000 square kilometres (9).


American slough grass conservation

The American slough grass is classified as endangered in Illinois and threatened in Michigan (2), which protects the species from collection or deliberate harm. This grass also occurs on protected land in Michigan, including Isle Royale National Park (4). In the United States, some wetlands are regulated by the federal government under the Clean Water Act of 1972, and farmers who modify existing wetlands may lose their benefits from the United States Department of Agriculture. The United States Fish & Wildlife Service’s National Wetlands Inventory produces in-depth reports and surveys of the extent and quality of wetlands in the United States (9) (10), and since 1989 a ‘no net loss policy’ has ensured that the overall amount of wetland in the United States will remain near its current level (10). American slough grass occurs over a wide range, and some populations are known to exist within protected land (4).


Find out more

Find out more about American slough grass:

Find out more about the status of wetlands in North America:

Find out more about plant conservation in North America:



This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:



A plant that lives or grows for just one year.
Modified leaf at the base of a flower.
The reproductive shoot of a plant, which bears a group or cluster of flowers.
A plant that normally lives for more than two years. After an initial period, the plant usually produces flowers once a year.
An inflorescence (the flower-bearing reproductive shoot of a plant) in which the individual flowers all have distinct stalks and are attached to a central stem. The flowers at the base open first, and new flowers are produced at the tip as the shoot grows.


  1. Catalogue of Life (May, 2014)
  2. United States Department of Agriculture - American sloughgrass (May, 2014)
  3. Minnesota Board of Water & Soil Resources - American sloughgrass (May, 2014)
  4. Michigan Natural Features Inventory - Beckmannia syzigachne (May, 2014)
  5. United States Department of Agriculture - Beckmannia syzigachne (May, 2014)
  6. Boe, A. and Wynia, R. (1985) Germination, forage yield, and seed production of American sloughgrass (Beckmannia syzigachne). Journal of Range Management, 38(2): 114-116.
  7. Iowa State University, Department of Ecology, Evolution and Organismal Biology - American slough grass (May, 2014)
  8. United States Forest Service - Wet Meadows (April, 2014)
  9. United States Environmental Protection Agency - Wetlands (April, 2014)
  10. United States Fish & Wildlife Service, National Wetlands Inventory - Status and Trends of Wetlands in the Conterminous United States 2004 to 2009 (April, 2014)

Image credit

American slough grass  
American slough grass

© Matt Lavin / Montana State University

Matt Lavin
Montana State University


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