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For information on Wisconsin's rare plants, contact:
Kevin Doyle
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Shinners' Three-awned Grass (Aristida dichotoma)


Life history

Species overview

Shinners' Three-awned Grass (Aristida dichotoma), a State Special Concern plant, is found on dry sandy bluff edges. Blooming occurs throughout August; fruiting occurs late August through early October. The optimal identification period for this species is late August through early October.

Synonyms: Aristida dichotoma var. dichotoma

Identification

  • Distinguishing characteristics: Distinguished by its spiraled middle awn and glumes which are both longer than the lemma.
  • Flower characteristics: Panicles terminal and axillary, the terminal usually less than 10 cm long, the lateral (axillary) smaller.
  • Fruit characteristics: Glumes about equal, 6 to 8 mm long; lemma 5 to 6 mm long; central awn spirally coiled, horizontally bent, 3 to 6 mm long, the lateral awns erect, about 1 mm long.
  • Leaf characteristics: Leaves thread-like with many of the edges rolling up and inward toward the center of the leaf; blades short, the lower mostly flat, the upper involute.

Phenology

  • Blooming phenology: throughout August
  • Fruiting phenology: late August through early October
  • Optimum time to identify: late August through early October

Other

  • Growth form: Graminoid
  • Vegetative reproduction:
  • Life cycle: Annual
  • Comments: Associated Species: Selaginella rupestris, Agalinis gattingeri, Poa compressa, Polygonum tenue, Aristida purpurascens.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Shinners' Three-awned Grass (Aristida dichotoma). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.


Documented locations of Aristida dichotoma in the Natural Heritage Inventory Database as of March 2012.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS1
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found on dry sandy bluff edges.
  • Soils: Dry, sandy or sterile soils.

Natural communities

This table lists the natural communities that are associated with Shinners' Three-awned Grass. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Dry Prairie 3
Pine Relict 2

Ecological landscapes

This table lists the ecological landscape association scores for Shinners' Three-awned Grass. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Shinners' Three-awned Grass (Aristida dichotoma) has very few known occurrences in the state and is of the highest priority for conservation; we encourage you to consult with your District Ecologist or NHI Botanist for specific recommendations for your site.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • Avoid locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).
  • Maintain low canopy cover areas for savanna and barrens plant species.
  • Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.

Photos


Shinners' Three-awned Grass  [Photo #23417]

Photo © Emmet Judziewicz.

Shinners' Three-awned Grass  [Photo #24512]

Photo © Kevin Doyle.

Shinners' Three-awned Grass  [Photo #23533]

Photo by Ryan O'Connor, WDNR.


Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Tuesday, January 14, 2014
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition