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Kevin Doyle

Marsh Grass-of-Parnassus (Parnassia palustris)

Life history

Species overview

Marsh Grass-of-Parnassus (Parnassia palustris), a State Threatened plant, is found on clay bluffs along Lake Superior, and in cold northern fens, and calcareous sand or gravel pits. Blooming occurs early August through early September; fruiting occurs throughout September. The optimal identification period for this species is throughout August.

Synonyms: Parnassia multiseta, Parnassia palustris ssp. Neogaea, Parnassia palustris var. neogaea


  • Distinguishing characteristics: Cauline leaf as large as basal leaves.
  • Flower characteristics: Flowers bisexual; petals white, 5- to 17-nerved, 9 to 13 mm, half to twice as long as the lance-triangular, green sepals.
  • Fruit characteristics: Numerous oblong, angular seeds.
  • Leaf characteristics: Mostly basal with one cauline leaf, entire, palmately veined; blades of basal leaves broadly ovate to almost rotund, 1 to 3 cm, three quarters to fully as wide, broadly rounded or more often cordate at the base; cauline leaf as large as the basal, broadly ovate, sessile and cordate-clasping.


  • Blooming phenology: early August through early September
  • Fruiting phenology: throughout September
  • Optimum time to identify: throughout August


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Alnus crispa, A. rugosa, Salix spp., Carex lacustris, Typha latifolia, Mimulus glabratus, Juncus brevicaudatus, Solidago canadensis, Equisetum arvense, Fragaria virginiana.

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 Marsh Grass-of-Parnassus (Parnassia palustris). 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 Parnassia palustris in the Natural Heritage Inventory Database as of March 2012.

Summary Information
State StatusTHR
Federal Status in Wisconsinnone
State RankS1S2
Global RankG5
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 on clay bluffs along Lake Superior, and in cold northern fens, and calcareous sand or gravel pits.
  • Soils: Moist to wet, sandy, gravelly, or calcareous soils.

Natural communities

This table lists the natural communities that are associated with Marsh Grass-of-Parnassus. 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
Boreal Rich Fen 2
Clay Seepage Bluff 2
Northern Sedge Meadow 2

Ecological landscapes

This table lists the ecological landscape association scores for Marsh Grass-of-Parnassus. 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 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

  • Maintain and restore open habitat through selective clearing and brushing.
  • Minimize disturbance to hydrology, including soil disturbance from rutting.
  • Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.


Marsh Grass-of-Parnassus  [Photo #10079]

Parnassia palustris habitat, Marinette County.

Photo © Emmet Judziewicz.

Marsh Grass-of-Parnassus  [Photo #1199]

Photo © William S. Alverson.

Marsh Grass-of-Parnassus  [Photo #12486]

Photo by  staff, WDNR.

Marsh Grass-of-Parnassus  [Photo #12396]

Photo © William S. Alverson.

Marsh Grass-of-Parnassus  [Photo #1348]

Photo © William S. Alverson.

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: Tuesday, October 07, 2014
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