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Thickspike (Elymus lanceolatus ssp. psammophilus)

Life history

Species overview

Thickspike (Elymus lanceolatus ssp. psammophilus), a Wisconsin Threatened plant, is found on Lake Michigan dunes and beaches. Blooming occurs throughout June; fruiting occurs early July through late August. The optimal identification period for this species is early June through late August.

Synonyms: Agropyron dasystachyum, Agropyron elmeri, Agropyron riparum, Agropyron riparium, Elytrigia dasystachya, Elytrigia riparia


  • Distinguishing characteristics: Disjunct from natural range of var. dasystachya. Glumes more slender and attenuate, approaching form of E. smithii.
  • Flower characteristics: Spikes stiff, erect, 6 to 25 cm, the middle internodes 7 to 12+ mm; spikelets 11 to 20+ mm, mostly 3 to 7-flowered, occasionally in pairs.
  • Fruit characteristics: Glumes slender, attenuate, up to half as long as the lemmas; lemmas 7 to 10 mm, acute, sometimes shortly awn-tipped, densely villous; anthers 4 to 5 mm.
  • Leaf characteristics: Involute or sometimes flat, 1 to 3.5 mm wide, firm, glabrous to scaberulous or sometimes pilose.


  • Blooming phenology: throughout June
  • Fruiting phenology: early July through late August
  • Optimum time to identify: The optimal identification period for this species is early June through late August


  • Growth form: Graminoid
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Comments: Associated Species: Ammophila breviligulata, Calamovilfa longifolia ssp. magna, Tanacetum huronense.

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 Thickspike (Elymus lanceolatus ssp. psammophilus). 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 Elymus lanceolatus ssp. psammophilus in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS2
Global RankG5T3
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 Lake Michigan dunes and beaches.
  • Soils: Sandy soils.

Natural communities

This table lists the natural communities that are associated with Thickspike. 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
Great Lakes Beach 3
Great Lakes Dune 3

Ecological landscapes

This table lists the ecological landscape association scores for Thickspike. 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.

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.

Management guidance

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

  • Avoid disturbance to shorelines and the forest-beach interface.
  • Survey for and control invasive plants prior to conducting timber operations, as these can be spread by vehicles and often respond vigorously to increased light; see forestry BMPs for invasive species.
  • Avoid any activities which destabilize the dune, including the use of off-road vehicles, removal of native vegetation and pedestrian recreational overuse.


Thickspike Photo.

Photo © William S. Alverson.

Thickspike Photo.

Photo © J. Hale.

Thickspike Photo.

Elymus lanceolatus ssp psammophilus in foreground showing overall delicate aspect of the plant. Compare to Ammophila breviligulata in the background.

Photo by Owen Boyle, Wisconsin DNR.

Thickspike Photo.

Elymus lanceolatus ssp psammophilus leaves are thin with inrolled margins, compared to the robust, wide, flat leaves of Leymus arenarius, a non-native invasive plant.

Photo by Owen Boyle, Wisconsin DNR.

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: Wednesday, May 05, 2021
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