Large Toothwort (Cardamine maxima)

Life history

Species overview

Large Toothwort (Cardamine maxima), a Wisconsin Special Concern plant, is found in rich mesic floodplain terraces. Blooming occurs late April through early June; fruiting occurs throughout June. The optimal identification period for this species is late April through late May.

Synonyms: Cardamine X maxima, Dentaria maxima

Identification

• Distinguishing characteristics: Purple 4-parted flowers; 3 distinctly alternate leaves with 3-parted with ovate leaflets, the margins toothed and distinctly ciliolate. In contrast, C. diphyllya has white flowers and 2 opposite, 3-parted leaves with margins glabrous to merely scabrous.
• Flower characteristics: Four-parted, purplish, bell-shaped flowers with 11 to 17 mm long petals; peduncle often sparsely pubescent.
• Fruit characteristics: Elongated, thin pods 2 to 4 cm long.
• Leaf characteristics: Alternate, distinctly 3, each leaf divided into 3 leaflets; leaflet margins toothed and distinctly ciliolate.

Phenology

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

Other

• Growth form: Forb-erect
• Vegetative reproduction: Rhizomatous
• Life cycle: Annual/perennial
• Comments: Associated Species: Acer saccharum, Tilia americana, Claytonia virginica, Erythronium spp., Cardamine concatenata, C. laciniata.

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 Large Toothwort (Cardamine maxima). 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 rich mesic floodplain terraces.
• Soils: Rich, mesic soils.

Natural communities

This table lists the natural communities that are associated with Large Toothwort. 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 Large Toothwort. 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 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.
• Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.

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.

Other resources

Links to additional Large Toothwort information

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