Common names: rat-tail fescue; red-tailed fescue; sixweeksgrass; zorro annual fescue
Festuca myuros (rat-tail fescue) is an annual grass (family Poaceae), probably originally from Eurasia and currently widely distributed in California and around the world. It has very narrow leaves and an inflorescence that resembles a rat’s tail. Its inflorescence has branches that are erect, rather than reflexed like its native counterpart, Festuca microstachys. The lowest glume of each spikelet is also small, typically < 2mm. This species is one of many introduced annual grasses that competes with and reduces habitat for native grassland species and increases fire risk. Festuca myuros has been implicated in affecting native vegetation less frequently than several other non-native annual grasses, in part because of its smaller stature. A non-native sister species, Festuca bromoides, is very similar in habit but has not yet been reviewed for the inventory.
High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.
A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
* – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
-* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.
Festuca myuros Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
Weed Management Notes
No Weed RIC Management Notes are available for this species. Check for information on other species in the genus on the Weed RIC site.
Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.
There are no Symposium presentations associated with this species yet.
Other Festuca myuros Information
CalPhotos - Images of plants taken mostly in California.
Calflora - Distribution map and records of this species in California.
EDDMapS - Distribution of this species in North America.
Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.
Additional photos
Festuca myuros (rat-tail fescue) flower spike. Photo: Ron Vanderhoff
