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Giant Pinedrops (Pterospora andromedea)

Life history

Species overview

Giant Pinedrops (Pterospora andromedea), a Wisconsin Endangered plant, is found in white pine stands in northern dry-mesic forests. Blooming occurs early June through late August; fruiting occurs early July through late August. The optimal identification period for this species is early July through late August.

Synonyms: None


  • Distinguishing characteristics: Monotypic. Similar species much smaller with erect (rather than nodding) fruit.
  • Flower characteristics: Numerous nodding flowers in a long, terminal raceme, 1 to 3 dm; bell-shaped corolla 6 to 7 mm, white to more often reddish, with spreading recurved lobes measuring 1 to 2 mm.
  • Fruit characteristics: Capsule strongly nodding, many-seeded; seeds with a broad, terminal wing.
  • Leaf characteristics: Numerous and scale-like, especially below.


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


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Pinus strobus, Juniperus communis, Poa pratensis.

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 Giant Pinedrops (Pterospora andromedea). 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 Pterospora andromedea in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
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 in white pine stands in northern dry-mesic forests.
  • Soils: Dry soils.

Natural communities

This table lists the natural communities that are associated with Giant Pinedrops. 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 Giant Pinedrops. 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 locating landings, staging areas, or access routes on or near known populations.
  • Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.
  • 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.

Management guidance

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

  • This species is closely associated with a particular fungus called Rhizopogon and various conifers in the family Pinaceae. Because it is not clear how to manage for soil fungi populations, management which disturbs the soil or removes conifers near populations of Pterospora andromedea should be avoided.


Giant Pinedrops Photo.

Photo by  staff, Wisconsin DNR.

Giant Pinedrops Photo.

Photo by  staff, Wisconsin DNR.

Giant Pinedrops Photo.

Giant pinedrops is extremely rare in Wisconsin, where it occurs at only a few locations. The Boreal Forests of the northern Door Peninsula provide habitat for this species.

Photo © Kitty Kohout.

Giant Pinedrops Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Giant Pinedrops Photo.

Photo © J. Zoreb.

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