Share your observations

Share your observations of plants or non-game animals with the Natural Heritage Inventory

Rare animals
Find rare and non-game animals.
Rare plants
Learn about plants on the Natural Heritage Working List.
Rare lichens
Discover Wisconsin's lichens.
Natural communities
Explore Wisconsin's natural communities.
Other features
Discover unique resources.
Rare plant monitoring annual report

Catch up with the latest news in rare plant monitoring efforts throughout Wisconsin.

Eagle license plate

Help care for rare plants and animals by ordering an Endangered Resources plate.

Contact information
For information on Wisconsin's rare plants, contact:
Kevin Doyle

Nodding Rattlesnake-root (Prenanthes crepidinea)

Life history

Species overview

Nodding Rattlesnake-root (Prenanthes crepidinea), a Wisconsin Endangered plant, is found often in openings in mesic to dry-mesic hardwoods, particularly along creeks and in seepage areas. Blooming occurs early August through late September; fruiting occurs throughout September. The optimal identification period for this species is early August through late September.

Synonyms: Nabalus crepidineus


  • Distinguishing characteristics: Often distinguished by winged leaf stem.
  • Flower characteristics: Inflorescence corymb-like, generally branched, flowers maturing from the bottom upward, heads nodding; flowers bisexual, 15 to 38, ochre-colored; pappus (modified calyx) tan or sordid.
  • Fruit characteristics: Achenes elongate, smooth, mostly reddish-brown.
  • Leaf characteristics: Alternate, smooth or rough above, generally with short, coarse, stiff hairs at least on the midrib and main veins, most petiolate, elliptic to deltoid, cordate, coarsely toothed to occasionally shallowly lobed or entire, only gradually reduced upward; blade to 25 cm long by 20 cm wide.


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


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Tilia americana, Laportea canadensis, Celtis occidentalis, Fraxinus americana, Cryptotaenia canadensis, Asarum canadense, Circaea lutetiana, Parthenium integrifolium, Prunus spp., Quercus alba, Pyrus ioensis, Osmorhiza claytonii.

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 Nodding Rattlesnake-root (Prenanthes crepidinea). 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 Prenanthes crepidinea in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG4
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 often in openings in mesic to dry-mesic hardwoods, particularly along creeks and in seepage areas.
  • Soils: Moist soils.

Natural communities

This table lists the natural communities that are associated with Nodding Rattlesnake-root. 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 Nodding Rattlesnake-root. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Ecological landscape score
Southwest Savanna 2
Western Coulee and Ridges 2

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 direct disturbance to sensitive microsites such as seeps, cliffs, and moss-covered boulders.
  • 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.
  • Avoid rapid and dramatic reductions in canopy cover or basal area in wet areas to reduce risk of swamping.
  • 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.
  • Buffer management around unique microhabitats such as ephemeral ponds, seeps, etc.


Nodding Rattlesnake-root Photo.

The winged petiole of basal leaves, best observed in the spring, is a diagnostic characteristic of nodding rattlesnake-root.

Photo by Kevin Doyle, Wisconsin DNR.

Nodding Rattlesnake-root Photo.

Photo by  staff, Wisconsin DNR.

Nodding Rattlesnake-root Photo.

Photo © B. Summers.

Nodding Rattlesnake-root Photo.

Photo © B. Summers.

Nodding Rattlesnake-root Photo.

Photo © B. Summers.

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: Wednesday, May 05, 2021
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