PROTECTING WISCONSIN'S BIODIVERSITY

 
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Scientific Name Common Name Global Rank State Rank Federal Status WI Status

Auricled Twayblade (Listera auriculata)

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Photo by Ryan LeBlanc

 

Counties with Mapped NHI Occurrences

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 early-July through late-August. The optimal identification period for this species is early-June through early-July.

Neottia auriculata, Ophrys auriculata

 
 
 
Identification

Auricled twayblade is an erect forb, 10-25cm tall, with up to 20 pale green flowers. Its sepals and lateral petals are lance-ovate to oblong, 3-4.5mm long, the 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. Its fruit is a capsule. Leaves are opposite, arranged in a single pair, each leaf ovate or round-ovate and broadly rounded at the base, 2-5cm long and longer than the peduncle.

It can be distinguished from L convallarioides by the broad-based lip (vs narrow at the base) and glabrous pedicels (vs finely glandular pubescent), though the main axis of the inflorescence may be pubescent. It is distinguished from L cordata by its lip, which is shallowly cleft into 2 rounded lobes (vs cleft halfway to its base into two sharp-pointed lobes) and longer leaves (over 2.5cm in L auriculata vs under 2.5cm in L cordata).

Phenology and Reproduction

Blooming occurs early-June through early-July, fruiting early-July through late-August.

Perennial. The optimal identification period for this species is early-June through early-July.

Ecology and Associated Species

Associated species include Alnus rugosa, Thalictrum dasycarpum, Liparis loeselii, Cornus racemosa, Fraxinus pennsylvanica, and Ophioglossum vulgatum.

Habitat

Auricled twayblade prefers wet, sandy soils and is found only on semi-stabilized, alluvial sand under alders.

Avoidance Measures and Management Guidance

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 and use care with spot spraying.

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.

Wildlife Action Plan

Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.

For more information, contact

Kevin Doyle
Conservation Biologist
tel:+1-608-416-3377