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Contact information
For information on Wisconsin's rare plants, contact:
Kevin Doyle
608-416-3377

Auricled Twayblade (Listera auriculata)

Life history

Species overview

Auricled Twayblade (Listera auriculata), a Wisconsin Endangered plant, is found only on semi-stabilized, alluvial sand under alders. Blooming occurs early June through early July; fruiting occurs early July through late August. The optimal identification period for this species is early June through early July.

Synonyms: Neottia auriculata, Ophrys auriculata

Identification

  • Distinguishing characteristics: Distinguished from L. convallarioides by the flower with a broad based lip (vs. narrow at base) and pedicels glabrous (vs. finely glandular pubescent), though the main axis of the inflorescence may be pubescent. Distinguished from L. cordata by the lip shallowly cleft into 2 rounded lobes (vs. cleft halfway to its base into two sharp-pointed lobes) and longer leaves (over 2.5 cm in L auriculatavs. under 2.5 cm in L cordata).
  • Flower characteristics: Flowers pale green, numbering up to 20; sepals and lateral petals lance-ovate to oblong, 3 to 4.5 mm long; lip pale green, oblong in outline, slightly constricted at the middle and cleft at the summit for about 25% of its length, maintaining its width to the rounded base where it bears a pair of minute, downward-pointing, ear-shaped appendages.
  • Fruit characteristics: Capsule.
  • Leaf characteristics: Opposite, arranged in a single pair, each leaf ovate or round-ovate and broadly rounded at the base, 2 to 5 cm long and longer than the peduncle.

Phenology

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

Other

  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Alnus rugosa, Thalictrum dasycarpum, Liparis loeselii, Cornus racemosa, Fraxinus pennsylvanica, Ophioglossum vulgatum.

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 Auricled Twayblade (Listera auriculata). 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 Listera auriculata in the Natural Heritage Inventory Database as of July 2015.


Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG3G4
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 only on semi-stabilized, alluvial sand under alders.
  • Soils: Wet, sandy soils.

Natural communities

This table lists the natural communities that are associated with Auricled Twayblade. 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
Alder Thicket 3

Ecological landscapes

This table lists the ecological landscape association scores for Auricled Twayblade. 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 broadcast spraying of herbicides; use care with spot spraying.
  • 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.

Management guidance

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

  • 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.

Photos


Auricled Twayblade  Photo.

Photo © Jeff Hapeman, Wisconsin State Herbarium

Auricled Twayblade  Photo.

Photo © Jim McEvoy.

Auricled Twayblade  Photo.

Photo © Ryan LeBlanc.


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: Friday, August 10, 2018
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