|Vulpia microstachys-Parvisedum pumilum-Lasthenia californica association. Photo courtesy of Julie Evans, California Native Plant Society.|
Vulpia microstachys (Nutt.) Benth. var. ciliata (Beal) Lonard & Gould , Eastwood small sixweeks grass
The genus Vulpia is distinguished by annual life form and cleistogamous breeding habit, while Festuca is perennial and chasmogamous . Not all systematists support the separation of these closely aligned genera [33,84,109,111].SYNONYMS:
Distributions of the varieties overlap considerably. Eastwood small sixweeks grass occurs from central Washington south to northern Baja California and western Arizona . Desert small sixweeks grass is distributed from Washington east to western Montana and south to northern Baja California, western Nevada, and southern New Mexico [104,114]. Confusing small sixweeks grass is the least common variety, occurring from south-central Washington to southern California. Pacific small sixweeks grass occurs from Washington east to western Montana and south to Baja California Sur [65,104]. Plants database provides a distributional map of small sixweeks grass and its infrataxa.
The following biogeographic classification systems are a guide to where small sixweeks grass may occur. Except for the West Coast, precise distribution information for small sixweeks grass is limited, and small sixweeks grass may occur in ecosystems and plant communities that are not listed below.ECOSYSTEMS :
California grasslands: Small sixweeks grass is common to dominant in California's valleys and low foothills . On the San Joaquin Experimental Range near Fresno, it was tallied as the 2nd most common grass over a 5-year period, comprising 9% to 17% cover .
It was also important in California's pristine valley grasslands. Small sixweeks grass was probably abundant in California prairie in favorable years. Historically, relative proportion of small sixweeks grass and other native annual grasses was probably greatest on dry sites . Grasslands on serpentine soils are among the few remnants of California prairie, because nonnative annual grasses cannot compete with serpentine-adapted native annual grasses on serpentine sites . Pacific small sixweeks grass is typically the dominant grass on serpentine soils . Pacific small sixweeks grass is also noted on relict purple needlegrass (Nassella pulchra) communities . Holland  lists Eastwood and Pacific small sixweeks grasses as dominant with serpentine reedgrass (Calamagrostis ophitidis) on serpentine bunchgrasslands of the Coast Ranges, Sierra Nevada, and Transverse Ranges.Palouse prairie: In 1913, Weaver  recorded Pacific small sixweeks grass as the dominant annual of bluebunch wheatgrass (Pseudoroegneria spicata) steppe in southeastern Washington and adjacent Idaho. It occurred between bunchgrass interspaces at an average density of 150 plants/m², and also occurred in rimrock communities on upper slopes .
|© 2004 Carol W. Witham|
Small sixweeks grass is an annual. Culms are 5.9 to 30 inches (15-75 cm) long and spreading, growing solitary or in small tufts. The inflorescence is a narrow, 0.8- to 9-inch-long (2-24 cm), many-flowered panicle. Spikelets are 5.5 to 10 mm long. Lemmas are 4 to 9.5 mm long, and awned. Awns are relatively long (3.5-20 mm) . The fruit is a caryopsis, ranging from 3.5 to 6 mm in length [22,42,56,67,111].RAUNKIAER  LIFE FORM:
Breeding system/pollination: Small sixweeks grass is largely cleistogamous. Gene flow within and among populations is minimal to nonexistent due to cleistogamous habit [54,68]; however, there are occasional chasmogamous plants .
Seed production: In a greenhouse study, small sixweeks grass grown in serpentine soil significantly (p=0.05) increased aboveground vegetative and seed biomass when fertilized with either N-P-K with calcium amendment or compost with calcium amendment . Information on small sixweeks grass seed production in the field was not found.
Seed dispersal: Seed is dispersed primarily by wind . The seed awns provide a mechanism for possible animal dispersal, although animal dispersal is not documented.
Seed banking: Small sixweeks grass maintains a seed bank [8,101]. On annual grassland at the Hopland Field Station, California, Vulpia species (V. microstachys, V. bromoides, and V. myuros) had a mean density of 1,227 seeds/dm² in 1974 and 438 seeds/dm² in 1975. Mean seed:germinant ratios were 10:1 and 6:1 in 1974 and 1975, respectively. Vulpia grasses were pooled due to difficulty of identifying species in the field . On a serpentine site near Colusa, California, small sixweeks grass seed density averaged 400/m² .
Germination: Few studies to date (2006) address germination requirements of small sixweeks grass. It appears to require neither scarification nor stratification [101,103], although such treatments or processes may increase germination. Desert small sixweeks grass seed collected from the Intermountain region showed 85% mean germination . Sweeney  obtained 92.2% mean germination (range=80%-100%) of unstratified, unscarified Pacific small sixweeks grass collected in California.
Small sixweeks grass seed tolerates moderate heat for short periods. In a heat tolerance test, 65% of unscarified Pacific small sixweeks grass seeds that sustained a maximum temperature of 160 °F (70°C) for 5 minutes remained germinable (see Immediate Fire Effect on Plant for further information on this study) . Plant Response to Fire also provides further information on fire effects on small sixweeks grass germination.
As an annual, small sixweeks grass cover may fluctuate from year to year , and sometimes no viable seed may germinate in a seemingly favorable germinating season. On the Hopland Field Station, small sixweeks grass and other Vulpia species showed "good" germination at the beginning of the fall growing season, but viable seed was still plentiful in the seed bank in spring .
Soil or litter cover may increase germination. In a greenhouse study, Pacific small sixweeks grass germination was improved by covering seed with either 0.3 or 0.5 inch (0.8 or 1.2 cm) of topsoil. Serpentine litter had no effect on germination. Gulmon  suggested that Pacific small sixweeks grass seeds benefit from the increased wetting time afforded by topsoil coverage. Pacific small sixweeks grass showed significantly (p=0.007) reduced cover on plots where mulch was removed compared to plots with intact mulch (9.98% and 25.95%, respectively) .
Seedling establishment/growth: As of 2006, little information was available on growth rates of small sixweeks grass. Although some small sixweeks grass ecotypes are adapted to serpentine soils, the low calcium levels characteristic of such soils may inhibit seedling root growth . After seedlings at the Hopland Field Station had reached several weeks of age, they suffered little mortality through winter and spring .
Asexual regeneration: Because it is an annual, small sixweeks grass does not sprout from the root crown after it produces seed. It dies. However, Vulpia species may die back and sprout from the root crown when wet weather follows a short-term dry period within the growing season .SITE CHARACTERISTICS:
Soils: Small sixweeks grass most commonly grows in loose, sandy soils , although it may also grow on clays [42,67]. In California small sixweeks grass prefers open sites, and is often found on thin or heavily compacted soils . Small sixweeks grass tolerates low-nutrient soils . Desert small sixweeks grass, for example, grows on serpentine or shale soils . North of San Francisco, Pacific small sixweeks grass cover was positively correlated with a low soil calcium:magnesium ratio, which is characteristic of serpentine soils, although mean plant biomass was lower for Pacific small sixweeks grass growing on serpentine soils compared to plants on nonserpentine soils . Pacific small sixweeks grass also grows on clay soils with favorable phosphorus and available water contents .
Aspect: Eastwood small sixweeks grass was most common on southeast-facing slopes (21% frequency) and least important on northeast-facing slopes (3% frequency) on annual grasslands of the Jasper Ridge Biological Preserve in San Mateo County, California. It only occurred on serpentine soils .
Elevation: Small sixweeks grass is documented at the following elevations:
|Arizona||low to mid-elevations |
|California||sea level to 4,900 feet (0-1,500 m) [42,95]|
|Nevada||3,600-6,200 feet (1,200-1,900 m) |
|Utah||<6,000 feet (1,830 m) |
|California||mid-Oct. ||March-June [76,95]||----|
|Intermountain region||----||May-June ||late July-late Sept. |
|Baja California Norte||----||May-July ||----|
Fire regimes: Fire is important in retaining open structure in some of the communities where small sixweeks grass is common, but fire was historically infrequent in other plant communities where it occurs. Frequent fire in palouse prairies and annual grasslands maintains the grasslands by preventing invasion of woody plants and reducing litter [82,90,100,115]. Fire plays a more variable ecological role in shrublands where sixweeks grass is important. Some of the shrublands (e.g., chamise (Adenostoma fasciculatum) and other chaparral types) depend on moderate-interval (30-100 years), stand-replacing fire ; others are adapted to mixed-severity fires (e.g., big sagebrush (Artemisia tridentata)) [3,21,71,96]; while some desert shrubland types such as creosotebush (Larrea tridentata) are poorly adapted to fire . Descriptions of fire regimes of communities where small sixweeks grass is important follow.
Palouse prairie: Fire frequencies for bluebunch wheatgrass-dominated habitats vary considerably, depending on the associated species . Most mean fire intervals are less than 30 years. Estimates for historical fire intervals in the Snake River Canyon of Idaho for bluebunch wheatgrass-Idaho fescue-Sandberg bluegrass (Festuca idahoensis-Poa secunda) communities are 10 to 25 years .
Annual grasslands: Because they are dominated by nonnative annuals, annual grasslands have no "natural" fire regime. There are no data and few historic records of presettlement fire return intervals in pristine California prairie. Probable mean fire intervals (estimates of fire intervals that are derived from historical or very limited physical evidence) for California prairie are frequent: approximately every 1 to 2 years. Probable mean fire intervals for today's annual grasslands are 20 to 30 years .
Sagebrush/bunchgrass: Prior to the 1890s, probably only a few grass species occurred in early postfire sagebrush (Artemisia spp.) communities of the Great Basin. Of these, small sixweeks grass and sixweeks grass (Vulpia octoflora) might have been most important. Generally, native Vulpias would increase for a few postfire years, then be suppressed by bunchgrasses such as bluebunch wheatgrass, bottlebrush squirreltail (Elymus elymoides), and Idaho fescue, and by shrubs such as basin big sagebrush (A. tridentata ssp. tridentata) and rabbitbrush (Chrysothamnus spp.) . Historic fire return interval ranged from around 20 to 100 years [46,115,116]. Cheatgrass and medusahead (Taeniatherum caput-medusae), nonnative annual grasses, have altered fire regimes and successional patterns in some sagebrush communities. Fine fuel loads from dry cheatgrass and/or medusahead can support fire-return intervals as short as 3 to 6 years .
Desert shrub: Small sixweeks grass is a common component of southwestern steppe communities. For example, it had 40% frequency in a vegetation survey in a creosotebush-white bursage (Ambrosia dumosa) community in the Mojave Desert . Fire is infrequent in pristine creosotebush-white bursage, Joshua tree (Yucca brevifolia), and saguaro (Carnegiea gigantea) communities. Discontinuity of fine fuels in most years hinders the spread of fire, which was historically uncommon to rare [15,17,19,48,79]. In most years, pristine stand structure of these southwestern desert shrub communities is widely spaced woody plants, bare interspaces, and some perennial bunchgrasses [13,17,18,91]. During wet winters and springs, annuals such as sixweeks grass increase fuels loads. Biomass accumulations from native annuals following an exceptionally wet growing season may provide enough fine fuels to carry a fire in desert ecosystems that otherwise rarely burned [11,102].
Historically, dry sixweeks grass and other native annuals rarely fueled fires in desert shrublands , but nonnative, invasive annual grasses including red brome (B. rubens) and schismus have increased fuel loads from historic levels. While native annual grasses mostly grow in the protective shade of shrubs, nonnative grasses also grow in shrub interspaces, increasing fuel continuity and fire frequency and severity on invaded sites. Ecological consequences are serious, as most southwestern desert plants are poorly adapted to frequent and/or stand-replacing fire [17,18]. Nonnative annual grasses outcompete small sixweeks grass on most desert shrub sites (see Invasives). For detailed information on fine fuel production of small sixweeks grass, red brome, schismus, and other Mojave Desert annuals, see the Research Project Summary Nonnative annual grass fuels and fire in California's Mojave Desert.
Chaparral: Historic fire return intervals in chamise and mixed-chaparral ranged from 10 to 90 years [82,101]. Intervals between fires were longer in communities dominated by nonsprouting shrubs, such as bigberry manzanita (Arctostaphylos glauca), than in communities dominated by sprouting shrubs such as chamise .
Coastal sage scrub chaparral: Documentation of historic fire intervals in coastal sage scrub is lacking. Current fire return intervals vary widely. Total area burned strongly correlates with precipitation during the previous winter, with heaviest burning occurring after wet years. Fire is rare following drought . Vogl  estimated an average fire interval of 20 years for lightning-ignited fire in chaparral adjacent to coastal sage scrub. Fire severity is generally higher in coastal sage scrub than in seral chaparral due to higher litter loading and the higher percentage of terpenes in coastal sage scrub vegetation [34,69]. For a California sagebrush-eastern Mojave buckwheat (Artemisia californica-Eriogonum fasciculatum) community on the Cleveland National Forest, California, fire records show that stand-replacing fire occurs at approximate 28-year intervals. Sixweeks grass is noted in early postfire succession in the community .
Fuels: Dry sixweeks grass is a "poor" fuel. Because it contributes little fine fuel biomass and crumbles rapidly upon drying, small sixweeks grass typically contributes little fine fuel biomass during the fire season [17,106]. During prescribed burning on the Mojave Desert, native annual vegetation including sixweeks grass was unable to sustain fire despite abundant growth after above-average winter rains .
Productivity on serpentine soils is generally low. Pacific small sixweeks grass biomass on California's serpentine annual grasslands, where Pacific small sixweeks grass is often dominant, averages around 280 g/m² [37,70]. Mean biomass of Pacific small sixweeks grass on serpentine annual grassland of the Jasper Ridge Biological Preserve was 4.4 g/m² over 4 years (s x =1.7 g/m², range=1.8-8.6 g/m²) .
The following table provides fire return intervals for plant communities and ecosystems where small sixweeks grass is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|silver fir-Douglas-fir||Abies amabilis-Pseudotsuga menziesii var. menziesii||>200|
|grand fir||Abies grandis||35-200 |
|California chaparral||Adenostoma and/or Arctostaphylos spp.||<35 to <100|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||Artemisia tridentata var. tridentata||12-43 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [4,21,71]|
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (40**) [107,117]|
|coastal sagebrush||Artemisia californica||<35 to <100|
|saltbush-greasewood||Atriplex confertifolia-Sarcobatus vermiculatus||<35 to <100|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||5-100|
|blue grama-tobosa prairie||Bouteloua gracilis-Pleuraphis mutica||<35 to <100 |
|cheatgrass||Bromus tectorum||<10 [83,112]|
|California montane chaparral||Ceanothus and/or Arctostaphylos spp.||50-100 |
|curlleaf mountain-mahogany*||Cercocarpus ledifolius||13-1,000 [5,97]|
|blackbrush||Coleogyne ramosissima||<35 to <100 |
|California steppe||Festuca-Danthonia spp.||<35 [82,100]|
|western juniper||Juniperus occidentalis||20-70|
|creosotebush||Larrea tridentata||<35 to <100 |
|wheatgrass plains grasslands||Pascopyrum smithii||<5-47+ [82,115]|
|pine-cypress forest||Pinus-Cupressus spp.||<35 to 200 |
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Colorado pinyon||Pinus edulis||10-400+ [28,32,58,82]|
|Pacific ponderosa pine*||Pinus ponderosa var. ponderosa||1-47 |
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [3,6,64]|
|mountain grasslands||Pseudoroegneria spicata||3-40 (x = 10) [2,3]|
|coastal Douglas-fir*||Pseudotsuga menziesii var. menziesii||40-240 [3,75,88]|
|Pacific coast mixed evergreen||Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii||<35|
|California oakwoods||Quercus spp.||<35 |
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
|coast live oak||Quercus agrifolia||2-75 |
|canyon live oak||Quercus chrysolepis||<35 to 200|
|blue oak-foothills pine||Quercus douglasii-P. sabiniana||<35|
|Oregon white oak||Quercus garryana||<35 |
|California black oak||Quercus kelloggii||5-30 |
|western redcedar-western hemlock||Thuja plicata-Tsuga heterophylla||>200 |
Fire in any season may reduce the seed bank . Small sixweeks grass seed in litter or lying on the soil surface is most vulnerable to fire kill [101,117]. Most surface fires probably do not harm small sixweeks grass seed that is buried in soil [40,80]. However, even buried seed can die when exposed to heat for long periods of time. In laboratory experiments, small sixweeks grass seed buried in moist soil died after a 1-hour exposure to 115 to 121 °F (46-49 °C) temperatures , while most Pacific small sixweeks grass seed exposed to temperatures of 160 °F (70 °C) for only 5 minutes remained viable. Germination of unscarified Pacific small sixweeks grass seed dropped as follows :
|50 °C||60 °C||70 °C||80 °C|
In another laboratory study, Sweeney  tested Pacific small sixweeks grass's maximum heat tolerance at 320 °F (160 °C). In a pot experiment, he obtained 100% germination of fresh, untreated Pacific small sixweeks grass seeds buried at 0.25 inch (0.63 cm), while germination dropped to 68% after excelsior was burned on top of similarly treated seeds. Charate slightly lowered germination of Pacific small sixweeks grass seed from 100% to 95% .DISCUSSION AND QUALIFICATION OF FIRE EFFECT:
|Prefire soil samples|
|Heat and charate||Site 1||Site 2|
|Postfire soil samples||0||0|
|Field emergence on burn||0||0|
It is likely that high fire intensities killed small sixweeks grass seed on the prescribed burn sites.PLANT RESPONSE TO FIRE:
Harrison and others  found a significant (p<0.01) soil-fire interaction for Pacific small sixweeks grass on the California Natural Reserve in northern California. Pacific small sixweeks grass frequency (%) was highest on burned serpentine soils :
Daubenmire  found a July 1961 wildfire promoted Pacific small sixweeks grass near Clarkston, Washington. The fire occurred in an old field succeeding to a bluebunch wheatgrass-Sandberg bluegrass community. Percent cover of Pacific small sixweeks grass was low under all conditions, but relative frequency increased in early postfire years :
|Postfire year 2||Postfire year 4||Postfire year 12|
|Burned sites||Cover (%)||0||1||1|
|Unburned sites||Cover (%)||0||trace||1|
Often, fire may have only a slight positive effect to no effect on small sixweeks grass. Small sixweeks grass was present but uncommon on both burned and unburned sites 6 years after wildfire in a blackbrush community in southwestern Utah . In a survey of maritime burns, Eastwood small sixweeks grass had 4% frequency on earl seral burns (postfire years 1-5) in maritime coast live oak in Santa Barbara County, California. It was not present on maritime chamise chaparral burns .DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
|Postfire year 2||Postfire year 4||Postfire year 12|
Fall and spring prescribed burning in east-central Oregon had no significant effect on small sixweeks grass density or frequency in postfire year 1 or 2 . See the Research Project Summary of this work for more information on fire effects on small sixweeks grass and 60 additional grass, forb, and woody plant species.FIRE MANAGEMENT CONSIDERATIONS:
Palatability/nutritional value: Sampson and others  rate palatability of green small sixweeks grass as good for cattle and horses and fair for domestic sheep. Initially nutritious, nutritional value drops quickly as plants senesce .
Cover value: Vulpia species provide poor cover for small mammals and birds .VALUE FOR REHABILITATION OF DISTURBED SITES:
Pacific small sixweeks grass greatly increased in cover following addition of nitrogen fertilizer on serpentine annual grassland of the Jasper Ridge Biological Preserve, dominating some fertilized plots to near exclusion of other species. Density of Pacific small sixweeks grass averaged 290 plants/m² on fertilized plots and 150 plants/m² on unfertilized plots. Most annuals (native or not) declined with nitrogen amendment to the serpentine soil .
Invasives: Nonnative annual grasses can interfere with establishment and growth of small sixweeks grass. Cheatgrass has relegated small sixweeks grass to minor status on dry portions of the Columbia Plateau, where small sixweeks grass was once abundant . In a greenhouse experiment using small sixweeks grass, red brome (a nonnative species), and pinnate tansymustard (Descurainia pinnata, a native species) seed from the Mojave Desert, red brome extracted soil water faster and had higher total plant nitrogen content compared to small sixweeks grass and pinnate tansymustard. Red brome also showed higher germination rates compared to small sixweeks grass and pinnate tansymustard, although small sixweeks grass produced more total seed. A growth chamber study showed biomass of small sixweeks grass was significantly (p<0.01) reduced when grown with red brome in nitrogen-fertilized desert soil compared to small sixweeks grass grown with red brome in unfertilized desert soil .
Pacific small sixweeks grass is adapted to low-nitrogen soils and can outcompete nonnative annual grasses on low-nitrogen serpentine soils. Nonnative Italian ryegrass (Lolium multiflorum) and soft chess (Bromus hordeaceus) are infrequent on serpentine soils unless nitrogen is added . In a survey of California annual grasslands on 92 sites, Pacific small sixweeks grass frequency averaged 48.5% on serpentine sites and 5.5% on nonserpentine soils. Frequency was not significantly affected by distance from roads .A field inventory and follow-up experiment in grasslands north of San Francisco showed evidence of growth interference from nonnative annuals, and also showed that Pacific small sixweeks grass shows ecotypic differences. Pacific small sixweeks grass was most common (and dominant) on rocky serpentine slopes, intermediate on serpentine meadows (which were dominated by native forbs), and least common on nonserpentine grasslands (which were dominated by nonnative annual grasses). On plots treated with herbicide and seeded with Pacific small sixweeks grass collected from nonserpentine sites, total Pacific small sixweeks grass seedling emergence and survival was greatest on nonserpentine soils and lowest on serpentine soils. However, Pacific small sixweeks grass seed from rocky serpentine slopes showed best emergence and survival on serpentine soils .
1. Albertson, F. W.; Weaver, J. E. 1944. Nature and degree of recovery of grassland from the great drought of 1933 to 1940. Ecological Monographs. 14(4): 393-479. 
2. Arno, Stephen F. 1980. Forest fire history in the Northern Rockies. Journal of Forestry. 78(8): 460-465. 
3. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. 
4. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. 
5. Arno, Stephen F.; Wilson, Andrew E. 1986. Dating past fires in curlleaf mountain-mahogany communities. Journal of Range Management. 39(3): 241-243. 
6. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. 
7. Barrett, Stephen W. 1984. Fire history of the River of No Return Wilderness: River Breaks Zone. Final Report. Missoula, MT: Systems for Environmental Management. 40 p. plus appendices. 
8. Bartolome, James W. 1979. Germination and seedling establishment in California annual grasslands. Journal of Ecology. 67: 272-281. 
9. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. 
10. Bishop, Gene; Bunter, Walt. 1999. Basic seed data supporting NRCS vegetative guides. Plant Materials Tech. Note CA-5 (Revision 2). Lockeford, CA: U.S. Department of Agriculture, Natural Resources Conservation Service. 16 p. 
11. Bowns, James E.; West, Neil E. 1976. Blackbrush (Coleogyne ramosissima Torr.) on southwestern Utah rangelands. Research Report 27. Logan, UT: Utah State University, Utah Agricultural Experiment Station. 27 p. 
12. Boyd, Steve. 1999. Vascular flora of the Liebre Mountains, western Transverse Ranges, California. Aliso. 18(2): 93-139. 
13. Brooks, M. L.; Matchett, J. R. 2006. Spatial and temporal patterns of wildfires in the Mojave Desert, 1980-2004. Journal of Arid Environments. 67(Supplement): 148-164. 
14. Brooks, Matthew L. 1999. Alien annual grasses and fire in the Mojave Desert. Madrono. 46(1): 13-19. 
15. Brooks, Matthew L.; Matchett, John R. 2003. Plant community patterns in unburned and burned blackbrush (Coleogyne ramosissima Torr.) shrublands in the Mojave Desert. Western North American Naturalist. 63(3): 282-298. 
16. Brooks, Matthew L.; Pyke, David A. 2001. Invasive plants and fire in the deserts of North America. In: Galley, Krista E. M.; Wilson, Tyrone P., eds. Proceedings of the invasive species workshop: The role of fire in the control and spread of invasive species; Fire conference 2000: the 1st national congress on fire ecology, prevention, and management; 2000 November 27 - December 1; San Diego, CA. Misc. Publ. No. 11. Tallahassee, FL: Tall Timbers Research Station: 1-14. 
17. Brooks, Matthew L.; United States Geological Survey. 2000. Competition between alien annual grasses and native annual plants in the Mojave Desert. The American Midland Naturalist. 144(1): 92-108. 
18. Brooks, Matthew Lamar. 1998. Ecology of a biological invasion: alien annual plants in the Mojave Desert. Riverside, CA: University of California. 186 p. Dissertation. 
19. Brown, David E.; Minnich, Richard A. 1986. Fire and changes in creosote bush scrub of the western Sonoran Desert, California. The American Midland Naturalist. 116(2): 411-422. 
20. Burcham, L. T. 1957. California range land: An historico-ecological study of the range resource of California. Sacramento, CA: State of California, Department of Natural Resources, Division of Forestry. 247 p. 
21. Burkhardt, Wayne J.; Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology. 57: 472-484. 
22. Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, Noel H.; Reveal, James L.; Holmgren, Patricia K. 1977. Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 6: The Monocotyledons. New York: Columbia University Press. 584 p. 
23. Daubenmire, Rexford. 1975. Plant succession on abandoned fields, and fire influences, in a steppe area in southeastern Washington. Northwest Science. 49(1): 36-48. 
24. Davis, Frank W.; Borchert, Mark I.; Odion, Dennis C. 1989. Establishment of microscale vegetation pattern in maritime chaparral after fire. Vegetatio. 84: 53-67. 
25. Davis, Frank W.; Hickson, Diana E.; Odion, Dennis C. 1988. Composition of maritime chaparral related to fire history and soil, Burton Mesa, Santa Barbara County, California. Madrono. 35(3): 169-195. 
26. Dittberner, Phillip L.; Olson, Michael R. 1983. The plant information network (PIN) data base: Colorado, Montana, North Dakota, Utah, and Wyoming. FWS/OBS-83/86. Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service. 786 p. 
27. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
28. Floyd, M. Lisa; Romme, William H.; Hanna, David D. 2000. Fire history and vegetation pattern in Mesa Verde National Park, Colorado, USA. Ecological Applications. 10(6): 1666-1680. 
29. Franck, Valerie M.; Hungate, Bruce A.; Chapin, F. Stuart, III; Field, Christopher B. 1997. Decomposition of litter produced under elevated CO2: dependence on plant species and nutrient supply. Biogeochemistry. 36(3): 223-237. 
30. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
31. Gelbard, Jonathan L.; Harrison, Susan. 2003. Roadless habitats as refuges for native grasslands: interactions with soil, aspect, and grazing. Ecological Applications. 13(2): 404-415. 
32. Gottfried, Gerald J.; Swetnam, Thomas W.; Allen, Craig D.; Betancourt, Julio L.; Chung-MacCoubrey, Alice L. 1995. Pinyon-juniper woodlands. In: Finch, Deborah M.; Tainter, Joseph A., eds. Ecology, diversity, and sustainability of the Middle Rio Grande Basin. Gen. Tech. Rep. RM-GTR-268. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 95-132. 
33. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. 
34. Green, Lisle R. 1981. Burning by prescription in chaparral. Gen. Tech. Rep. PSW-51. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 36 p. 
35. Greenlee, Jason M.; Langenheim, Jean H. 1990. Historic fire regimes and their relation to vegetation patterns in the Monterey Bay area of California. The American Midland Naturalist. 124(2): 239-253. 
36. Gulmon, S. L. 1992. Patterns of seed germination in Californian serpentine grassland species. Oecologia. 89(1): 27-31. 
37. Gulmon, S. L.; Chiariello, N. R.; Mooney, H. A.; Chu, C. C. 1983. Phenology and resource use in three co-occurring grassland annuals. Oecologia. 58(1): 33-42. 
38. Halsey, Richard W. 2005. After the fire. In: Fire, chaparral, and survival in southern California. 1st ed. San Diego, CA: Sunbelt Publications, Inc: 85-97. 
39. Harrison, S.; Inouye, B. D.; Safford, H. D. 2003. Ecological heterogeneity in the effects of grazing and fire on grassland diversity. Conservation Biology. 17(3): 837-845. 
40. Heady, H. F.; Bartolome, J. W.; Pitt, M. D.; Savelle, G. D.; Stroud, M. C. 1992. California prairie. In: Coupland, R. T., ed. Natural grasslands: Introduction and western hemisphere. Ecosystems of the World 8A. Amsterdam, The Netherlands: Elsevier Science Publishers B. V.: 313-335. 
41. Heady, Harold F. 1977. Valley grassland. In: Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of California. New York: John Wiley and Sons: 491-514. 
42. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. 
43. Hitchcock, A. S. 1951. Manual of the grasses of the United States. Misc. Publ. No. 200. Washington, DC: U.S. Department of Agriculture, Agricultural Research Administration. 1051 p. [2nd edition revised by Agnes Chase in two volumes. New York: Dover Publications, Inc.]. 
44. Hobbs, R. J.; Gulmon, L. L.; Hobbs, V. J.; Mooney, H. A. 1988. Effects of fertilizer addition and subsequent gopher disturbance on a serpentine annual grassland community. Oecologia. 75(2): 291-295. 
45. Holland, Robert F. 1986. Preliminary descriptions of the terrestrial natural communities of California. Sacramento, CA: California Department of Fish and Game. 156 p. 
46. Houston, Douglas B. 1973. Wildfires in northern Yellowstone National Park. Ecology. 54(5): 1111-1117. 
47. Huenneke, Laura Foster; Hamburg, Steven P.; Koide, Roger; Mooney, Harold A.; Vitousek, Peter M. 1990. Effects of soil resources on plant invasion and community structure in Californian serpentine grassland. Ecology. 71(2): 478-491. 
48. Humphrey, Robert R. 1974. Fire in the deserts and desert grassland of North America. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 365-400. 
49. Hyder, D. N.; Bement, R. E. 1964. Sixweeks fescue as a deterrent to blue grama utilization. Journal of Range Management. 17: 261-264. 
50. Janes, Eric Bertram. 1969. Botanical composition and productivity in the California annual grassland in relation to rainfall. Berkeley, CA: University of California, Berkeley. 47 p. Thesis. 
51. Johnson, Craig A. 1989. Early spring prescribed burning of big game winter range in the Snake River Canyon of westcentral Idaho. In: Baumgartner, David M.; Breuer, David W.; Zamora, Benjamin A.; Neuenschwander, Leon F.; Wakimoto, Ronald H., comps. Prescribed fire in the Intermountain region: Forest site preparation and range improvement: Symposium proceedings; 1986 March 3-5; Spokane, WA. Pullman, WA: Washington State University, Department of Natural Resources, Cooperative Extension: 151-155. 
52. Jorgensen, Kent R.; Stevens, Richard. 2004. Seed collection, cleaning, and storage. In: Monsen, Stephen B.; Stevens, Richard; Shaw, Nancy L., comps. Restoring western ranges and wildlands. Gen. Tech. Rep. RMRS-GTR-136-vol-3. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 699-716. 
53. Jurjavcic, N. L.; Harrison, S.; Wolf, A. T. 2002. Abiotic stress, competition, and distribution of the native annual grass Vulpia microstachys in a mosaic environment. Oecologia. 130(4): 555-562. 
54. Kannenberg, L. W.; Allard, R. W. 1967. Population studies in predominantly self-pollinated species. 8. Genetic variability in the Festuca microstachys complex. Evolution. 21: 227-240. 
55. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. In: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service. 
56. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 2 volumes]. Dissertation. 
57. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2nd ed. Berkeley, CA: University of California Press. 1085 p. 
58. Keeley, Jon E. 1981. Reproductive cycles and fire regimes. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; Lotan, J. E.; Reiners, W. A., tech. coords. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 231-277. 
59. Keeley, Jon E.; Zedler, Paul H. 1978. Reproduction of chaparral shrubs after fire: a comparison of sprouting and seeding strategies. The American Midland Naturalist. 99(1): 142-161. 
60. Kimball, Sarah; Schiffman, Paula M. 2003. Differing effects of cattle grazing on native and alien plants. Conservation Biology. 17(6): 1681-1693. 
61. Krueger, W. C.; Vavra, M.; Wheeler, W. P. 1980. Plant succession as influenced by habitat type, grazing management, and reseeding on a northeast Oregon clearcut. In: 1980 progress report--research in rangeland management. Special Report 586. Corvallis, OR: Oregon State University, Agricultural Experiment Station: 32-37. In cooperation with: U.S. Department of Agriculture, SEA-AR. 
62. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. 
63. Laude, Horton M. 1957. Comparative pre-emergence heat tolerance of some seeded grasses and of weeds. Botanical Gazette. 119(1): 44-46. 
64. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., tech. coords. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. 
65. Leon de la Luz, Jose Luis; Benet, Rocio Coria. 1993. Additions to the flora of the Sierra de la Laguna, Baja California Sur, Mexico. Madrono. 40(1): 15-24. 
66. Link, Steven O.; Gee, Glendon W.; Downs, Janelle L. 1990. The effect of water stress on phenological and ecophysiological characteristics of cheatgrass and Sandberg's bluegrass. Journal of Range Management. 43(6): 506-513. 
67. Lonard, Robert I.; Gould, Frank W. 1974. The North American species of Vulpia (Gramineae). Madrono. 22(5): 217-280. 
68. Lonard, Robert Irvin. 1970. A biosystematic study of the genus Vulpia (Gramineae). College Station, TX: Texas A&M University. 154 p. Dissertation. 
69. Malanson, George P.; O'Leary, John F. 1985. Effects of fire and habitat on post-fire regeneration in Mediterranean-type ecosystems: Ceanothus spinosus chaparral and Californian coastal sage scrub. Acta Oecologica. 6(20): 169-181. 
70. McNaughton, S. J. 1968. Structure and function in California grasslands. Ecology. 49: 962-972. 
71. Miller, Richard F.; Rose, Jeffery A. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. The Great Basin Naturalist. 55(1): 37-45. 
72. Minnich, Richard A. 1983. Fire mosaics in southern California and northern Baja California. Science. 219: 1287-1294. 
73. Montalvo, Arlee M.; McMillan, Paul A.; Allen, Edith B. 2002. The relative importance of seeding method, soil ripping, and soil variables on seeding success. Restoration Ecology. 10(1): 52-67. 
74. Mooney, H. A.; Hobbs, R. J.; Gorham, J.; Williams, K. 1986. Biomass accumulation and resource utilization in co-occurring grassland annuals. Oecologia. 70: 555-558. 
75. Morrison, Peter H.; Swanson, Frederick J. 1990. Fire history and pattern in a Cascade Range landscape. Gen. Tech. Rep. PNW-GTR-254. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 77 p. 
76. Munz, Philip A. 1974. A flora of southern California. Berkeley, CA: University of California Press. 1086 p. 
77. Niehaus, Theodore Ferdinand. 1961. A taxonomic and cytologic investigation of the Festuca microstachys complex. Davis, CA: University of California. 34 p. Thesis. 
78. O'Dell, Ryan E.; Claassen, Victor P. 2006. Relative performance of native and exotic grass species in response to amendment of drastically disturbed serpentine substrates. Journal of Applied Ecology. 43(5): 898-908. 
79. O'Leary, John F.; Minnich, Richard A. 1981. Postfire recovery of creosote bush scrub vegetation in the western Colorado Desert. Madrono. 28(2): 61-66. 
80. Odion, Dennis C. 2000. Seed banks of long-unburned stands of maritime chaparral: composition, germination behavior, and survival with fire. Madrono. 47(3): 195-203. 
81. Odion, Dennis C.; Davis, Frank W. 2000. Fire, soil heating, and formation of vegetation patterns in chaparral. Ecological Monographs. 70(1): 149-169. 
82. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; Gottfried, Gerald J.; Haase, Sally M.; Harrington, Michael G.; Narog, Marcia G.; Sackett, Stephen S.; Wilson, Ruth C. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-volume 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
83. Peters, Erin F.; Bunting, Stephen C. 1994. Fire conditions pre- and postoccurrence of annual grasses on the Snake River Plain. In: Monsen, Stephen B.; Kitchen, Stanley G., comps. Proceedings--ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 31-36. 
84. Radford, Albert E.; Ahles, Harry E.; Bell, C. Ritchie. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press. 1183 p. 
85. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
86. Renner, F. G.; Allred, B. W. 1962. Classifying rangeland for conservation planning. Agric. Handb. 235. Washington, DC: U.S. Department of Agriculture, Soil Conservation Service. 48 p. 
87. Richardson, Bland Z. 1985. Reclamation in the Intermountain Rocky Mountain Region. In: McCarter, M. K., ed. Design of non-impounding mine waste dumps; 1981 November; [Location of conference unknown]. New York: Society of Mining Engineers of the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc: 177-192. 
88. Ripple, William J. 1994. Historic spatial patterns of old forests in western Oregon. Journal of Forestry. 92(11): 45-49. 
89. Robinson, Richard Hayes. 1971. An analysis of ecological factors limiting the distribution of a group of Stipa pulchra associations. Korean Journal of Botany. 14(3): 61-80. 
90. Rowe, J. S. 1969. Lightning fires in Saskatchewan grassland. The Canadian Field-Naturalist. 83: 317-324. 
91. Rundel, Philip W.; Gibson, Arthur C. 1996. Ecological communities and processes in a Mojave Desert ecosystem: Rock Valley, Nevada. Cambridge; New York: Cambridge University Press. 369 p. 
92. Rydberg, Per Axel. 1909. Studies on the Rocky Mountain flora--19. Bulletin of the Torrey Botanical Club. 36: 531-541. 
93. Salo, L. F.; McPherson, G. R.; Williams, D. G. 2005. Sonoran Desert winter annuals affected by density of red brome and soil nitrogen. The American Midland Naturalist. 153(1): 95-109. 
94. Sampson, Arthur W.; Burcham, L. T. 1954. Costs and returns of controlled brush burning for range improvement in northern California. Range Improvement Studies No. 1. Sacramento, CA: California Department of Natural Resources, Division of Forestry. 41 p. 
95. Sampson, Arthur W.; Chase, Agnes; Hedrick, Donald W. 1951. California grasslands and range forage grasses. Bull. 724. Berkeley, CA: University of California College of Agriculture, California Agricultural Experiment Station. 125 p. 
96. Sapsis, David B. 1990. Ecological effects of spring and fall prescribed burning on basin big sagebrush/Idaho fescue--bluebunch wheatgrass communities. Corvallis, OR: Oregon State University. 105 p. Thesis. 
97. Schultz, Brad W. 1987. Ecology of curlleaf mountain mahogany (Cercocarpus ledifolius) in western and central Nevada: population structure and dynamics. Reno, NV: University of Nevada. 111 p. Thesis. 
98. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
99. Stickney, Peter F. 1989. FEIS postfire regeneration workshop--April 12: Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. 10 p. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 
100. Stromberg, Mark R.; Kephart, Paul; Yadon, Vern. 2001. Composition, invasibility, and diversity in coastal California grasslands. Madrono. 48(4): 236-252. 
101. Sweeney, James R. 1956. Responses of vegetation to fire: A study of the herbaceous vegetation following chaparral fires. University of California Publications in Botany. [Berkeley, CA: University of California Press]. 28(4): 143-250. 
102. Thatcher, Albert P. 1975. The amount of blackbrush in the natural plant community is largely controlled by edaphic conditions. In: Stutz, Howard C., ed. Wildland shrubs: Proceedings--symposium and workshop; 1975 November 5-7; Provo, Utah. Provo, Utah: Brigham Young University: 155-156. 
103. Turitzin, Stephen N. 1981. Nutrient limitations to plant growth in a California serpentine grassland. The American Midland Naturalist. 107(1): 95-99. 
104. U.S. Department of Agriculture, Natural Resources Conservation Service. 2007. PLANTS Database, [Online]. Available: http://plants.usda.gov/ [2007, February 22]. 
105. Utah State University. 2007. Grass manual on the web, [Online]. In: Manual of grasses for North America--Intermountain herbarium. Logan, UT: Utah State University (Producer). Available: http://herbarium.usu.edu/grassmanual/. 
106. Van Devender, Thomas R.; Felger, Richard S.; Burquez M., Alberto. 1997. Exotic plants in the Sonoran Desert region, Arizona and Sonora. In: Kelly, M.; Wagner, E.; Warner, P., eds. Proceedings, California Exotic Pest Plant Council symposium; 1997 October 2-4; Concord, CA. Volume 3. Berkeley, CA: California Exotic Pest Plant Council: 10-15. 
107. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. 
108. Vogl, Richard J. 1976. An introduction to the plant communities of the Santa Ana and San Jacinto Mountains. In: Latting, June, ed. Symposium proceedings: plant communities of southern California; 1974 May 4; Fullerton, CA. Special Publication No. 2. Berkeley, CA: California Native Plant Society: 77-98. 
109. Voss, Edward G. 1972. Michigan flora. Part I: Gymnosperms and monocots. Bloomfield Hills, MI: Cranbrook Institute of Science; Ann Arbor, MI: University of Michigan Herbarium. 488 p. 
110. Weaver, John Ernst. 1914. Evaporation and plant succession in southeastern Washington and adjacent Idaho. Plant World. 17(10): 273-294. 
111. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; Higgins, Larry C., eds. 1987. A Utah flora. The Great Basin Naturalist Memoir No. 9. Provo, UT: Brigham Young University. 894 p. 
112. Whisenant, Steven G. 1990. Postfire population dynamics of Bromus japonicus. The American Midland Naturalist. 123: 301-308. 
113. White, Thomas C.; Stephenson, John; Sproul, Fred. 1995. Postburn monitoring of the Eagle Fire: first year recovery on sites seeded with buckwheat and coastal sage. In: Keeley, Jon F.; Scott, Tom, eds. Brushfires in California: ecology and resource management: Proceedings; 1994 May 6-7; Irvine, CA. Fairfield, WA: International Association of Wildland Fire: 185-187. 
114. Wiggins, Ira L. 1980. Flora of Baja California. Stanford, CA: Stanford University Press. 1025 p. 
115. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p. 
116. Wright, Henry A.; Neuenschwander, Leon F.; Britton, Carlton M. 1979. The role and use of fire in sagebrush-grass and pinyon-juniper plant communities: A state-of-the-art review. Gen. Tech. Rep. INT-58. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 48 p. 
117. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505.