|Kneeland Penny-cress, Kneeland Prairie Penny Cress|
|(S. Wats.) P. Holmgren|
The following Participating Institutions are custodians for this species in the CPC National Collection:
The conservation of Thlaspi californicum is fully sponsored.
Holly Forbes contributed to this Plant Profile.
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)
Distribution & Occurrence
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 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)|
Conservation, Ecology & Research
Expansion of Kneeland Airport and CDFFP helitack base;
Spread of exotic species.
Development and implementation of a repatriation/introduction plan.
Restoration or creation of additional suitable habitat for Thlaspi californicum as opportunities become available.
Long term seed bank.
U.S. Fish & Wildlife Service. 2003. Recovery Plan for the Kneeland Prairie Penny-cress (Thlaspi californicum). Portland. USFWS.