CPC Plant Profile: Howell's Spectacular Thelypody
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Plant Profile

Howell's Spectacular Thelypody (Thelypodium howellii ssp. spectabilis)

The characteristic purple flowers with delicate white edging of Thelypodium howellii ssp. spectabilis. Photo Credit: Andrew Kratz
Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: Federally Threatened
  • Family: Brassicaceae
  • State: OR
  • Nature Serve ID: 156632
  • Date Inducted in National Collection: 02/10/1987

Thelypodium howellii ssp. spectabilis is found only in five populations, all in the Baker-Powder River Valley region bordered by the Wallowa and Elkhorn Mountains in northeastern Oregon. This member of the mustard family is listed as Endangered by the State of Oregon and Threatened by the Federal Government. However, all known populations of this rare plant are found on private land. Unless a project or particular land use on private land involves federal funds or violates state law, neither listing does anything to protect this rare plant. At the very center of the population distribution, a yearly tradition continues to threaten this species. To prepare for the annual July 4-5 rodeo, a large field is mowed every year to provide parking. In 1998, observations were made before and after the rodeo (USFWS 1999). Before the rodeo, 10,000 individual plants were observed on the parcel. After the rodeo, only 300 remained, with most of them along the fence line. That year, like many, the mowing occurred at the height of their growing season when the plants still had immature fruit. Nearly the entire reproductive output of that population was destroyed by a single pass of the mower.

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Updates
  • 09/30/2020
  • Propagation Research

Research on seed production, inbreeding depression, seed germination, and cultivation requirements of Thelypodium howellii spp. spectabilis (Gisler, pers. comm.).

  • 09/30/2020
  • Reintroduction

Experimental re-introduction project using both seeds and transplants from the greenhouse (Gisler, pers. comm.).

  • 09/30/2020
  • Propagation Research

Germination trials conducted at The Berry Botanic Garden. Seeds were subjected to either 8 weeks of cold stratification or no cold stratification followed by either constant 68F (20C) or alternating 50/68F (10/20C). In one trial no seeds germinated. In another trial, 40% of seeds subjected to cold stratification followed by constant 68F temperatures germinated. No other treatment resulted in any germination. The seed had been stored for at least ten years. Trials are now being conducted with recently collected seed (BBG File).

  • 09/30/2020
  • Orthodox Seed Banking

Seeds collected and stored in the Seed Bank at The Berry Botanic Garden.

  • 09/30/2020
  • Seed Collection

Seeds collected and stored in the Seed Bank at The Berry Botanic Garde

Nature Serve Biotics
  • 05/02/2017

Thelypodium howellii ssp. spectabilis is a subspecies endemic to a small range in eastern Oregon. The taxon is known from twelve sites. Much of the historical habitat and formerly known populations have been destroyed; all remaining populations occur on private land.

Edward Guerrant, Ph.D.
  • 01/01/2010

Threats, as stated by the U.S. Fish and Wildlife Service (USFWS 1999) and Meinke (1982) include: Habitat loss due to agricultural conversion. Habitat degradation due to grazing, agricultural conversion, and hydrological modifications. Plant destruct

Edward Guerrant, Ph.D.
  • 01/01/2010

As of 1999: Fewer than 11 small sites comprising 5 populations. The total number of individuals varies greatly in response to environmental conditions (temperature, rainfall, etc). Recent surveys have revealed individual populations as small as 10 individuals to as many as 16,000. As of the last surveys, the total population appears to be around 30,000 (USFWS 1999).

Edward Guerrant, Ph.D.
  • 01/01/2010

Research on seed production, inbreeding depression, seed germination, and cultivation requirements of Thelypodium howellii spp. spectabilis (Gisler, pers. comm.). Experimental re-introduction project using both seeds and transplants from the greenhouse (Gisler, pers. comm.). Germination trials conducted at The Berry Botanic Garden. Seeds were subjected to either 8 weeks of cold stratification or no cold stratification followed by either constant 68F (20C) or alternating 50/68F (10/20C). In one trial no seeds germinated. In another trial, 40% of seeds subjected to cold stratification followed by constant 68F temperatures germinated. No other treatment resulted in any germination. The seed had been stored for at least ten years. Trials are now being conducted with recently collected seed (BBG File).

Edward Guerrant, Ph.D.
  • 01/01/2010

Only two populations have ever been actively managed for the protection of Thelypodium howellii ssp. spectabilis. At the largest known site (not the greatest number of individuals) there was a conservation agreement between one landowner and the Oregon Department of Fish and Wildlife (ODFW). At another site, an agreement between the landowner and The Nature Conservancy recently expired (U.S. Fish and Wildlife Service, 1999). Listed Threatened by the Federal Government and listed Endangered by the State of Oregon. Portions of a few small sites occur on Oregon Department of Transportation (ODOT) right-of-ways. The department takes this rare plant into consideration when planning construction or mowing along the roads (USFWS 1999). Voluntary agreements between landowners and the U.S. Fish and Wildlife Service to limit grazing between April and July (USFWS 1999). A draft recovery plan is being developed (as of 2001). Seeds collected and stored in the Seed Bank at The Berry Botanic Garden.

Edward Guerrant, Ph.D.
  • 01/01/2010

Study life history, growth requirements, and general ecology (USFWS 1999). Limit livestock grazing when plants are actively growing. Limit mowing when plants are actively growing.

Edward Guerrant, Ph.D.
  • 01/01/2010

Collect and store seeds from across the range. Determine germination requirements. Determine propagation and reintroduction protocols.

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Photos
Nomenclature
Taxon Thelypodium howellii ssp. spectabilis
Authority (M.E. Peck) Al-Shehbaz
Family Brassicaceae
CPC Number 4275
ITIS 524751
USDA THHOS2
Common Names Howell's spectacular thelypody | Howell's thelypody
Associated Scientific Names Thelypodium howellii ssp. spectabilis | Thelypodium howellii var. spectabilis | Thelypodium howellii subsp. howellii | Thelypodium howellii | Thelypodium simplex
Distribution OR: Baker-Powder River valley region (Baker Co., Union Co.)
State Rank
State State Rank
Oregon S1
Habitat

Thelypodium howellii ssp. spectabilis grows in low elevation (3,000 to 3,300 ft (1,000-1,100 m)) river valleys and moist (often alkaline) plains in the Baker-Powder River valley region of northeastern Oregon. In this area, winters are cold and summers are hot and dry. The annual precipitation averages 10.6 in (27 cm), most of which falls as snow. Associated species include Sarcobatus vermiculatus (greasewood), Elymus cinereus (giant wild rye), Spartina gracilis (alkali cordgrass), Poa juncifolia (alkali bluegrass) and Chenopodium spp.

Ecological Relationships

Grazing greatly threatens Thelypodium howellii ssp. spectabilis, but the plants can recover once cattle impact is reduced or removed. In an area that has not been grazed for at least five years, plants have expanded into areas that were previously unoccupied (USFWS 1999). This taxon may be dependent on occasional flooding. It has been observed rapidly colonizing areas adjacent to streams that have recently flooded. It does not compete well with invading weedy vegetation (USFWS 1999).Thelypodium howellii ssp. spectabilis is a short-lived perennial that flowers once and then dies. Seeds geminate in the spring and grow to form a small, low growing rosette. In the spring of their second or later year, they """"bolt,"""" produce flowers, set seed, and then die. Because of its life history, it is especially dependent on frequent seed set to maintain populations. In the absence of adequate moisture, population numbers remain low. Several especially dry years may be particularly detrimental to the populations.

Pollinators
Common Name Name in Text Association Type Source InteractionID
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

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