Orcuttia pilosa
Encyclopedia
Orcuttia pilosa is a rare species of grass
known by the common name hairy Orcutt grass.
, where it grows only in vernal pool
s, 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 1997. In that year there were 25 known remaining populations of the grass, only 12 of which were considered stable.
is a crowded cluster of overlapping hairy spikelets.
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
known by the common name hairy Orcutt grass.
Distribution
It is endemic to the Central Valley of CaliforniaCalifornia
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it grows only in vernal pool
Vernal pool
Vernal pools, also called vernal ponds or ephemeral pools, are temporary pools of water. They are usually devoid of fish, and thus allow the safe development of natal amphibian and insect species...
s, a rare and declining type of habitat. Many known occurrences of the plant have been extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
as land in the heavily agricultural Central Valley has been altered, and it was federally listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
in 1997. In that year there were 25 known remaining populations of the grass, only 12 of which were considered stable.
Description
Orcuttia pilosa is a small, densely hairy annual bunchgrass forming tufts up to about 20 centimeters tall when growing erect. The inflorescenceInflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a crowded cluster of overlapping hairy spikelets.