Kneeland Prairie Pennycress / Center For Plant Conservation
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Plant Profile

Kneeland Prairie Pennycress (Noccaea fendleri ssp. californica)

Image of Thlaspi californicum in flower Photo Credit: © Br. Alfred Brousseau, Saint Mary's College
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Brassicaceae
  • State: CA
  • Nature Serve ID: 135369
  • Lifeform: Forb/herb
  • Date Inducted in National Collection:

Kneeland Prairie penny-cress is a perennial member of the mustard family (Brassicaceae). It is known only from Kneeland Prairie in Humboldt County, California, where it grows in coastal prairie on serpentine outcrops. It grows from 9.5 to 12.5 centimeters (3.7 to 4.9 inches) tall with a basal cluster of green to purplish, sparsely toothed leaves. The white flowers appear from March May. (Recovery Plan) Over 99 percent of the population is located on private land, with the remainder located on land owned by the California Department of Forestry and Fire Protection. (Recovery Plan)

Where is Kneeland Prairie Pennycress (Noccaea fendleri ssp. californica) located in the wild?


The single known population of Kneeland Prairie penny-cress occurs on serpentine soils, located approximately 12 miles from the Pacific Ocean, and approximately 2,800 feet above mean sea level. Climate in the prairie is marine-influenced, with average annual precipitation estimated at 60 inches, and frequent summer fog. Dominant plant species in its habitat typically include red fescue, common woolly sunflower, junegrass, large-fruited lomatium, and blue wildrye. No shrubs or trees are present.


The entire known distribution of Kneeland Prairie penny-cress occurs on Ashfield Ridge at elevations ranging from 792 to 841 meters (m) [2,600 to 2,760 feet (ft)]

States & Provinces:

Kneeland Prairie Pennycress can be found in California

Which CPC Partners conserve Kneeland Prairie Pennycress (Noccaea fendleri ssp. californica)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

Holly Forbes
  • 01/01/2010

Small population size Expansion of Kneeland Airport and CDFFP helitack base; Road realignment; Catastrophic events; Spread of exotic species.

Holly Forbes
  • 01/01/2010

The only known occurrence of Kneeland Prairie penny-cress includes five relatively distinct groups of plants all located within 300 m (980 ft) of each other. The species occupies an area divided by the Kneeland Airport and Mountain View Road. The known population consists of approximately 5,300 individuals. The five colonies occupy an estimated 0.3 ha (0.8 ac). (Recovery Plan)

Holly Forbes
  • 01/01/2010

Research necessary to enable maintenance and expansion of the existing population and establishment of new colonies. Critical aspects of the biology of Thlaspi californicum need to be studied, including genetic diversity within the species, seed viability, propagation methods, and specifics of the species habitat requirements. Development and implementation of a repatriation/introduction plan. Restoration or creation of additional suitable habitat for Thlaspi californicum as opportunities become available.

Holly Forbes
  • 01/01/2010

Determine optimum methods for seed germination and propagation. Long term seed bank.


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Taxon Noccaea fendleri ssp. californica
Authority (S. Watson) Al-Shehbaz & M. Koch
Family Brassicaceae
CPC Number 4288
ITIS 823356
Duration Perennial
Common Names Kneeland Penny-cress | Kneeland Prairie Penny Cress | Kneeland Prairie pennycress
Associated Scientific Names Thlaspi californicum | Noccaea fendleri ssp. californica | Thlaspi montanum var. californicum | Thlaspi alpestre var. californicum | Thlaspi glaucum subsp. californicum
Distribution The entire known distribution of Kneeland Prairie penny-cress occurs on Ashfield Ridge at elevations ranging from 792 to 841 meters (m) [2,600 to 2,760 feet (ft)]
State Rank
State State Rank
California S1
Ecological Relationships


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