Range Extent Comments: O. Number of Occurrences: 21 - 80 Number of Occurrences Comments: Of 36 occurrences, 12 are known to be extirpated, 9 are of unknown condition and only 6 are considered stable. Overall Threat Impact Comments: Very threatened due to agriculture, urbanization, overgrazing, non-native plants and trampling. Distribution Global Range: O. States and Canadian Provinces Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
The remaining known extant occurrences of hairy Orcutt grass occur in two areas: Glenn and Tehama Counties in the north, and Madera and Stanislaus Counties farther to the south. Like other vernal pool species, the biggest threat to and reason for the decline of hairy Orcutt grass is habitat loss and fragmentation caused by agricultural conversion and development. Although some of the remaining populations of hairy Orcutt grass, particularly in the north, are protected from agricultural conversion and development, these activities continue to threaten populations that are on private land. Development can cause the direct removal of vernal pool habitat, and development adjacent to vernal pools can also indirectly affect habitat by altering hydrology and creating new sources of runoff into the ecosystem.
Orcuttia pilosa is a rare species of grass known by the common name hairy Orcutt grass. It is endemic to the Central Valley of California , where it grows only in vernal pools , a rare and declining type of habitat. Many known occurrences of the plant have been extirpated as land in the heavily agricultural Central Valley has been altered, and it was federally listed as an endangered species in Orcuttia pilosa is a small, densely hairy annual bunchgrass forming tufts up to about 20 centimeters tall when growing erect.
Orcuttia pilosa hairy orcutt grass was collected in from a single locality in eastern Stanislaus County, California, at the time these specimens were considered to be a more robust form of O. The species was described O. The stems are erect or decumbent at the base. The inflorescence is spikelike and rather elongate, with the spikelets remote on the axis below and usually strongly congested above.