Round-leaved Orchis (Amerorchis rotundifolia)

Life history

Species overview

Round-leaved Orchis (Amerorchis rotundifolia), a Wisconsin Threatened plant, is found in cold, springy mixed conifer swamps. Blooming occurs late June through late July; fruiting occurs throughout July. The optimal identification period for this species is late June through late July.

Synonyms: Orchis rotundifolia, Orchis rotundifolia f. lineata, Orchis rotundifolia var. lineata

Identification

• Distinguishing characteristics: Basal leaf more broad than other orchids (greater width-to-length ratio) and 3 more or less prominent longitudinal veins in the single leaf.
• Flower characteristics: Flowers 1 cm in length, 10 to 15 or more forming a loose raceme; upper sepal and petals, which are 6 to 10 mm long, converge to form a pale pink to white hood, above a spurred, flat, 3-lobed lower lip that is typically spotted with dark purple.
• Fruit characteristics: Capsule greenish brown, erect, tapering at both ends; seeds tiny.
• Leaf characteristics: Single, round to oval basal leaf up to 9 cm in length.

Phenology

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

Other

• Growth form: Forb-erect
• Vegetative reproduction:
• Life cycle: Perennial
• Comments: Associated Species: Thuja occidentalis, Larix laricina, Picea mariana, Cardamine pratensis, Toxicodendron vernix, Eleocharis quinqueflora, Carex tenuiflora, C. gynocrates, C. lacustris, Equisetum fluviatile.

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 Round-leaved Orchis (Amerorchis rotundifolia). 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.

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 in cold, springy mixed conifer swamps.
• Soils: Wet soils.

Natural communities

This table lists the natural communities that are associated with Round-leaved Orchis. 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).

Ecological landscapes

This table lists the ecological landscape association scores for Round-leaved Orchis. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

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 direct disturbance to sensitive microsites such as seeps, cliffs, and moss-covered boulders.
• 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

• Minimize disturbance to hydrology, including soil disturbance from rutting.
• Avoid rapid and dramatic reductions in canopy cover or basal area in wet areas to reduce risk of swamping.
• Although maintaining high overall forest canopy is important, silvicultural techniques which open small gaps in the canopy may be beneficial to this species.

Other resources

Links to additional Round-leaved Orchis information

• Michigan Natural Features Inventory [PDF exit DNR]

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use