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Wafer-ash (Ptelea trifoliata ssp. trifoliata var. trifoliata)

Life history

Species overview

Wafer-ash (Ptelea trifoliata ssp. trifoliata var. trifoliata), a Wisconsin Special Concern plant, is found on dry, dolomite ledges in oak forests, in dry prairies, along railroad grades, and along rivers. Blooming occurs late May through early June; fruiting occurs throughout July. The optimal identification period for this species is late May through late September.

Synonyms: Ptelea baldwinii, Ptelea microcarpa, Ptelea serrata, Ptelea trifoliata var. deamiana


  • Distinguishing characteristics: The widely-winged fruits are very characteristic of this species. Ptelea can be distinguished from bladdernut (Staphylea trifolia) by its leaves, which are alternate in the former and opposite in the latter.
  • Flower characteristics: Flower heads flattened or slightly rounded, 4 to 8 cm wide, forming at the end of the branches; flowers many, greenish-white or yellowish-white; petals 4 to 7 mm long, oblong, and hairy.
  • Fruit characteristics: Fruits many, 15 to 25 mm wide, thin, flat, rounded, winged, appearing like two rounded pieces of paper pressed together with a small object in-between the 2 sheets, with many small veins; odor of hops.
  • Leaf characteristics: Alternate with long petioles, divided into 3 egg-shaped or elliptic leaflets.


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


  • Growth form: Shrub
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Quercus alba, Q. velutina, Juglans cinerea, Crataegus spp., Prunus virginiana, Rhus aromatica, Dirca palustris.

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 Wafer-ash (Ptelea trifoliata ssp. trifoliata var. trifoliata). 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 Ptelea trifoliata ssp. trifoliata var. trifoliata in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2
Global RankG5T5
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 dry, dolomite ledges in oak forests, in dry prairies, along railroad grades, and along rivers.
  • Soils: Dry, calcareous soils.

Natural communities

This table lists the natural communities that are associated with Wafer-ash. 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 Wafer-ash. 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.
  • Avoid locating landings, staging areas, or access routes on or near known populations.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Maintain partial canopy to encourage woodland species; avoid closed-canopy conditions.
  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).


Wafer-ash Photo.

Photo © Kitty Kohout.

Wafer-ash Photo.

Photo © R. Schulenberg.

Wafer-ash Photo.

Photo © Derek Anderson.

Wafer-ash Photo.

Photo © Kitty Kohout.

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