Floating Marsh Marigold (Caltha natans)

Life history

Species overview

Floating Marsh Marigold (Caltha natans), a Wisconsin Endangered plant, is found in shallow water in creeks, pools, ditches, and sheltered lake margins. It typically roots in mud, silt, or clay, and spreads by rooting at the nodes (Coffin & Pfannmuller, 1988). In Wisconsin, it has only been found in a small beaver-dammed stream within a boreal forest. Blooming occurs throughout July; fruiting occurs throughout August. The optimal identification period for this species is early July through late August.

Synonyms: Thacla natans

Identification

• Distinguishing characteristics: Stems slender and creeping, usually rooted on the shore and spreading into the water; flowers 1 cm wide with 20 to 40 pistils.
• Flower characteristics: Flowers pink or white, 1 cm wide, with 20 to 40 densely bunched pistils.
• Fruit characteristics: Follicles in heads of 20 to 50, each usually 3 to 6 mm long, sessile.
• Leaf characteristics: Alternate, 2 to 5 cm wide, kidney- to heart-shaped, edges may be smooth or toothed.

Phenology

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

Other

• Growth form: Aquatic forb-floating
• Vegetative reproduction:
• Life cycle: Perennial
• Comments: Associated Species: Typha latifolia, Salix sp., Lemna minor. Poisonous

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 Floating Marsh Marigold (Caltha natans). 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 shallow water in creeks, pools, ditches, and sheltered lake margins. It typically roots in mud, silt, or clay, and spreads by rooting at the nodes (Coffin & Pfannmuller, 1988). In Wisconsin, it has only been found in a small beaver-dammed stream within a boreal forest.
• Soils: Wet soils.

Natural communities

This table lists the natural communities that are associated with Floating Marsh Marigold. 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 Floating Marsh Marigold. 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 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.
• This species is likely sensitive to water quality. Following BMPs around streams and buffering associated drainages will reduce eutrophication and prevent water quality degradation.

Other resources

Links to additional Floating Marsh Marigold 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