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Oklahoma Grass-pink (Calopogon oklahomensis)

Life history

Species overview

Oklahoma Grass-pink (Calopogon oklahomensis), a plant, is found in prairies and rich woods. Blooming occurs June; fruiting occurs July through August. The optimal identification period for this species is throughout June.



  • Distinguishing characteristics: Flowers opening nearly simultaneously, corms elongate and forked, stigma typically flat against column surface, middle lip lobe usually much narrower than long, triangular to broadly rounded. In comparison, C. tuberosus flowers open sequentially; dilated distal portion of middle lip lobe is usually much wider than long and typically anvil shaped; stigma is at angle to column surface; corms are globose to elongate, not forked.
  • Flower characteristics: Flowers 2 to 7 (rarely 11), more than 1 cm apart and opening nearly simultaneously, magenta, pink to white; dorsal sepal strongly spreading to straight, obovate to oblanceolate, 14 to 25 x 5 to 8 mm, apex acuminate or acute; lateral sepals strongly spreading to straight, ovate to broadly lanceolate, slightly falcate, 15 to 22 x 8 to 10 mm, apex acuminate to apiculate; petals slightly falcate to straight, oblong to obpandurate, 11 to 20 x 5 to 8 mm, apex obtuse.
  • Fruit characteristics: Capsules erect; column persistent in mature capsule.
  • Leaf characteristics: Leaves toward bottom of scape, sheathing it, not appressed to inflorescences at flowering; blade linear-lanceolate, 7 to 35 cm x 5 to 15 mm.


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


  • Growth form: Forb-erect
  • Vegetative reproduction: Root sprouting
  • Life cycle: Perennial
  • Comments: Associated Species: None given for Wisconsin. Account in Flora of North America, Vol 26 (

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

Oklahoma Grass-pink (Calopogon oklahomensis) is on the "watch list." Watch list species have experienced, or are believed to have experienced, a statewide or range wide decline, but they are not currently tracked in the Natural Heritage Inventory (NHI) database. The watch list includes newly discovered species for which origin and rarity need to be determined, certain animals designated as Species of Greatest Conservation Need (SGCN) in the Wisconsin Wildlife Action Plan, and species that were tracked in the past but proved more abundant, widespread or less vulnerable than previously thought. Although watch list species are not actively tracked by NHI, occurrences documented during surveys are often stored by NHI, as these species could be tracked in the future if there is further evidence of their decline.

Summary Information
State Statusnone
Federal Status in WisconsinSOC
State RankSH
Global RankG2
Tracked by NHIW

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 prairies and rich woods.
  • Soils: Mesic, acidic, sandy to loamy soils.

Natural communities

This table lists the natural communities that are associated with Oklahoma Grass-pink. 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

Ecological landscapes

This table lists the ecological landscape association scores for Oklahoma Grass-pink. 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

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 broadcast spraying of herbicides; use care with spot spraying.
  • Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.
  • 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

  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).
  • 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.
  • Maintain and restore open habitat through selective clearing and brushing.
  • Minimize disturbance to hydrology, including soil disturbance from rutting.


Oklahoma Grass-pink Photo.

Photo © Hugh Wilson.

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