© Larry Blakely
© Larry Blakely
AUTHORSHIP AND CITATION:
McWilliams, Jack. 2003. Picrothamnus desertorum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ .
Artemisia spinescens D.C. Eat [12,16,28,33,65]
NRCS PLANT CODE :
The scientific name of budsage is Picrothamnus desertorum Nutt. (Asteraceae) [21,32,48].
Budsage is not known to hybridize with other species [30,69].LIFE FORM:
In the Surprise Valley of California, Young and others  list a community type of spiny hopsage (Grayia spinosa)/budsage/Indian ricegrass (Achnatherum hymenoides).
In the Churchill Canyon watershed of Nevada, Blackburn and others  describe a habitat type of black greasewood (S. vermiculatus)/budsage/desert needlegrass (A. speciosum) with a black greasewood/budsage community type as a component. They also delineate a shadscale (Atriplex confertifolia)/budsage community type in the same watershed. In Nevada's Cow Creek watershed there are several community types with budsage as a dominant. These are :
shadscale/budsage/winterfat (Krascheninnikovia lanata)
shadscale/budsage/bottlebrush squirreltail (Elymus elymoides)
In the Great Salt Lake Desert of Utah, Vest  describes a shadscale/budsage community type, and budsage is a "subdominant" in saltbush, horsebrush (Tetradymia spp.), and winterfat communities in desert shrub of western Utah . Wyoming's Red Desert has a cover type of budsage on alluvial flats .
Associates: Budsage occurs in several ecosystems. Its more common associates in some of these ecosystems include:
Desert shrub: shadscale, fourwing saltbush (A. canescens), valley saltbush (A. cuneata), Gardner's saltbush (A. gardneri), low rabbitbrush (Chrysothamnus viscidiflorus var. stenophyllus), green molly (Kochia americana), winterfat, spiny hopsage, and horsebrushes .
Sagebrush (Artemisia spp.): big sagebrush (Artemisia tridentata), birdfoot sagebrush (A. pedatifida), green rabbitbrush (C. viscidiflorus ), rubber rabbitbrush (C. nauseosus), granite prickly phlox (Leptodactylon pungens), western wheatgrass (Pascopyrum smithii), Indian ricegrass, and bluegrasses (Poa spp.) .
Sagebrush/grassland: big sagebrush, rubber rabbitbrush, western wheatgrass, and Indian ricegrass .
Salt-desert scrub: black greasewood, shadscale, Gardner's saltbush, fourwing saltbush, spiny hopsage, and winterfat .
Budsage is a native, summer-deciduous shrub . It is small, round, and prickly with a height of 4 to 10 inches (10-25 cm) and a spread of 8 to 12 inches (20-30 cm) . This low, spinescent, pungently aromatic shrub is profusely branched from the base [36,68]. After leaves and flowers fall from the plant, the flower stalks become woody, dry spines that may persist for several seasons . Budsage's fruits are an oblong or ellipsoid hairy achene . Dittberner and Olson  report budsage is endomycorrhizal.
Budsage is well adapted to xeric conditions. A layer of interxylary cork is formed annually over the last year's wood in both roots and stem. This layer of cork restricts upward movement of water to the very narrow zone of wood formed by the current year's growth and helps prevent water loss during the dormant season [36,68].
Roots: Budsage's root system is more branched and penetrates the soil more deeply than its associated shrub species. This allows budsage more efficient utilization of limited spring moisture [9,69]. However, the Institute for Land Rehabilitation  describes budsage's root system as shallow and fibrous. Budsage's extensive root system has a short, thick, vertical taproot up to 6 inches (15 cm) with many small horizontal side branches [68,69]. Budsage's root system grows primarily in the top 6 to 21.7 inches (15-55 cm) of soil ; but in gravel-free sandy soils, roots may extend up to 6 feet (1.8 m) .
Occasionally budsage produces
adventitious roots. This occurs when the lowest branches are completely covered
by soil. Budsage growing in bottomlands produce adventitious roots more often
than those growing on benches .
RAUNKIAER  LIFE FORM:
Breeding system: Budsage is monoecious .
Pollination: Budsage is wind pollinated .
Seed production: Good seed production occurs infrequently because budsage blooms so early in the spring developing embryos are frequently frozen .
Seed dispersal: Sagebrush seed in general has very poor dispersal. It lacks appendages for airborne transport by the wind or for attachment to animals. Most sagebrush seed falls beneath the parent plant and moves 3 feet (0.9 m) or less per generation . There is no specific information about seed dispersal for budsage.
Seed banking: No information
Germination: Budsage has small seeds, 641,250/per ounce (2,250/gm) , and germination is low . Flowerheads fall from the plant intact without breaking apart to release the seeds. Sometimes seed germinates while still in the head [36,68].
Seedling establishment/growth: Budsage was planted at the Black Butte mine in Wyoming as part of a wildlife improvement project and had 64% plant establishment the 1st year . In an experiment at the Desert Experimental Range in southwestern Utah, West  compared survival of budsage plants in grazed and ungrazed plots. In 4 ungrazed plots, seedlings of budsage established in 1935 and 1936 were counted until 1968. The spring of 1936 was drier than average and had poor seed production; shrub seedlings were rare. West  speculates that difference in survival for the 2 cohorts may be a function of initial plant size, especially root structure, with the 1936 cohort being influenced by the dry spring. Percent survivorship was:
|Year cohort counted||1935||1936||1937||1958||1968|
Wood  states soil must be wet for 30 days or budsage seedlings will not survive.
Asexual regeneration: Everett and others  tested propagation of Nevada shrubs by stem cuttings and found budsage to be one of the "...most easily propagated." Budsage also can regenerate by layering .SITE CHARACTERISTICS:
Elevation: Within the Great Basin budsage has an elevational range of 4,000 to 5,400 feet (1,219-1,646 m) . Altitudinal ranges for individual states are:
Arizona: 5,500 to 6,000 feet (1,676-1,829 m) 
California: 2,953 to 5,249 feet (900-1,600 m) 
Colorado: 4,500 to 8,000 feet (1,372-2,438 m) 
Nevada: 2,300 to 6,800 feet (701-2,073 m) 
Utah: 3,937 to 6,316 feet (1,200-1,925 m) 
Soils: Hutchings  states budsage ordinarily grows on slightly alkaline soil. The Institute for Land Rehabilitation  describes soils that budsage grows on as shallow, loamy, well-drained, and slightly alkaline. In a study of community types in the Great Salt Lake Desert of Utah, Vest  analyzed the soil in a shadscale/budsage community. His specific findings support the general statements of Hutchings  and The Institute for Land Rehabilitation . The pH of the soil in a shadscale/budsage community in Utah was :
|Depth of Samples|
|2 inches||2 inches (taken under shadscale plant)||2 inches (taken under budsage plant)||1 foot||2 feet|
Vest reported salt content, expressed as percent of the oven-dry weight of the samples as:
|Depth of sample||NaCl||Na2SO4||Na2CO3||NaHCO3||Total|
Soil texture in the same community was expressed as percent of oven-dry weight:
|Depth||Percent sand||Percent silt||Percent clays||Type|
|Very coarse||Coarse||Medium||Fine||Very Fine||Clay||Fine clay|
|2 inches (under shadscale)||1.0||1.6||2.6||9.0||18.8||46.0||2.4||24.8||clay loam|
|2 inches (under budsage)||1.0||1.6||2.2||8.8||15.2||47.2||4.8||14.8||loam|
|2 inches||0.7||2.0||2.5||5.0||22.4||39.6||2.4||24.8||clay loam|
|1 foot||4.0||5.6||8.0||13.2||11.2||24.0||7.2||25.2||clay loam|
|2 feet||5.2||6.6||10.6||16.4||10.9||19.6||3.6||24.0||sandy clay loam|
Early: Webb and others  characterize budsage as a pioneer species on disturbed sites in California's Death Valley National Monument.
Mid-successional: In the Great Salt Lake Desert of Utah, budsage is a mid-seral species on vegetated-dune communities .
Budsage is a component of climax vegetation on dense clay and
clayey soil types in Montana .
Budsage is a summer-deciduous shrub. Depending on growing season conditions budsage may initiate growth in early March and be dormant by late June . In a study observing phenology of desert shrubs in southern Nye County, Nevada, budsage always became dormant when daytime air temperatures were over 104 degrees Fahrenheit (40 oC) and did not break dormancy even after summer rains but always broke dormancy after fall rains . Chambers and Norton  discuss summer dormancy of budsage in Utah and state that when fall precipitation is sufficient to penetrate the soil from 9.8 to 11.8 inches (25-30 cm), budsage will break dormancy and produce new leaves but the stems will not elongate. This enables budsage to evade summer drought yet still take advantage of late-summer rain. Plants then remain green all winter providing succulent forage throughout winter and spring .
In southwestern Utah, Wood and Brotherson  gave supplemental water to a group of natural budsage seedlings and gave no supplemental water to another group. The group with supplemental water broke summer dormancy on August 28 and the group of seedlings without supplemental water broke summer dormancy 2 weeks later.
In 2 shadscale/galleta (Pleuraphis jamesii) sites in Nevada separated by 34.2 miles (55 km), budsage broke winter dormancy on March 22nd (southern-most site) and March 24th . Hutchings  states growth begins early in March or April as soon as the weather becomes warm, and flowers are produced in May. Seed is shed at the end of June .
Fire regimes: Fires in deserts are historically more rare than in most western ecosystems. The more arid the desert, the less fuel produced and the less frequent and severe are any fires that may occur. However, even though fire frequency and severity may be relatively low, fire's effect on the ecosystem may be severe. The Great Basin Desert is a cold-desert area characterized by a variety of shrubs with a generally sparse understory. Plant communities are usually dominated by big sagebrush or shadscale. Budsage is similar to shadscale in general growth form, and like shadscale communities, budsage communities rarely burn .
The following table provides fire return intervals where budsage may be an important component of the vegetation. Find further 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)|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||A. tridentata var. tridentata||12-43 |
|mountain big sagebrush||A. tridentata var. vaseyana||15-40 [2,8,38]|
|Wyoming big sagebrush||A tridentata var. wyomingensis||10-70 (40**) [63,70]|
|saltbush-greasewood||Atriplex confertifolia-Sarcobatus vermiculatus||< 35 to < 100|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||5-100|
|grama-galleta steppe||B. gracilis-Pleuraphis jamesii||< 35 to < 100|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||J. scopulorum||< 35|
|pinyon-juniper||Pinus-Juniperus spp.||< 35 |
|Mexican pinyon||P. cembroides||20-70 [39,58]|
|Colorado pinyon||P. edulis||10-400+ [22,24,34,41]|
|galleta-threeawn shrubsteppe||Pleuraphis jamesii-Aristida purpurea||< 35 to < 100 |
When budsage 1st shows signs of breaking winter dormancy, but before buds elongate, the bark can be easily removed from the previous season's growth by pulling. This condition is referred to as "slipping." At this time, budsage becomes palatable to domestic sheep. After the new twigs have elongated somewhat, budsage's palatability drops because the volatile oils increase. Cattle and horses seldom utilize budsage, possibly because of its aromatic oil content [68,69].
Smith and Beale  observed pronghorns in Utah from 1961 through 1970. They found during spring (16 March-15 June) budsage made up 18 to 35% of pronghorn diet. Budsage received highest utilization of any plant on western Utah deserts by pronghorns in the spring. The same study determined pronghorns ate no budsage during winter, budsage was <1% of the winter diet of cattle and 4% of the winter diet of domestic sheep. Gullion  lists budsage as "excellent" forage for Nevada pronghorn in spring.
Budsage is rated as "regularly, frequently, or moderately taken" by mule deer in Nevada in winter and is utilized by bighorn sheep in summer, but the importance of budsage in the diet of bighorns is not known .
Black-tailed jackrabbits and small rodents generally eat only leaves, small branches, and twigs of budsage. However, black-tailed jackrabbits may occasionally prune back an entire plant [68,69].
Chukars eat leaves and seeds of budsage in Nevada . Sage thrashers appear to prefer territories with great amounts of black sagebrush (Artemisia nova), shadscale, and budsage in the Great Basin . However, Wiens and others  did a statistical analysis of birds and shrubs in the Great Basin and found a significant (P<0.05) negative correlation between presence of budsage and sage thrashers and Brewer's sparrows. They found a significant (P<0.05) positive correlation between budsage and presence of mourning doves and loggerhead shrikes.
Palatability/nutritional value: Palatability of budsage is reported differently by different investigators. Chambers and Norton  report budsage is palatable to livestock the whole year. Cook and Harris  state budsage is "highly relished" by livestock in early spring, but later in spring, volatile oils increase and livestock avoid budsage. They also report budsage is not readily eaten during fall and winter because only a few dry leaves remain and only the spiny twigs and woody base are available to livestock.
In Utah Green and others  studied winter range of domestic sheep. They found domestic sheep frequently browsed 70% of budsage during the 1st contact. This represented all the domestic sheep could readily take, and only stumps of shoots and a limited amount of leafy material protected by coarse wood remained. Hutchings  describes budsage as a "good" forage species for domestic sheep that is browsed all winter long but is eaten most readily in late winter when growth begins. During this time budsage is of value to the welfare of browsing animals, especially where there is abundant dry grass to supplement their diet .
In a study of "major desert plants" during winter grazing season in Utah, Cook and Harris  determined average chemical constituents and average digestibility of budsage:
Average chemical constituents of budsage during winter grazing season
|ether extract (%)||total protein (%)||ash (%)||lignin (%)||cellulose (%)||other carbohydrates (%)||gross energy (kcal/lb)||phosphorus (%)||carotene (mg/lb)|
Average digestibility of chemical constituents, digestible protein, and metabolizable energy of budsage during winter grazing season
|ether extract (%)||total protein (%)||cellulose (%)||other carbohydrates (%)||gross energy (%)||dry matter||digestible protein (%)||metabolizable energy (kcal/lb)|
Cover value: Budsage is rated as poor cover for big game, upland game birds, and waterfowl. In Utah it is described as "fair" cover for nongame birds and small mammals .VALUE FOR REHABILITATION OF DISTURBED SITES:
Budsage is difficult to seed  but because of its shallow, fibrous root system, budsage can be used for soil stabilization and erosion control .
Two states list budsage as a plant suitable for reclamation or
landscaping. Utah describes budsage as suitable for transplanting in mountain chaparral,
pinyon/juniper (Pinus spp/Juniperus spp), Douglas-fir/white fir (Pseudotsuga
menziesii/Abies concolor), quaking aspen/lodgepole pine (Populus
tremuloides/Pinus contorta), ponderosa pine (P. ponderosa),
and sagebrush . The state of Nevada lists budsage as a "preferred" plant
for highway plantings in salt-desert shrub communities
Budsage is an indicator of alkaline soils .
OTHER MANAGEMENT CONSIDERATIONS:
Budsage is highly susceptible to effects of browsing. It decreases under browsing due to year-long palatability of its buds and is particularly susceptible to browsing in the spring when it is physiologically most active . Hutchings  recommends 50% of annual growth be the maximum browsed. Heavy browsing may kill budsage rapidly .
1. Ackerman, T. L.; Romney, E. M.; Wallace, A.; Kinnear, J. E. 1980. Phenology of desert shrubs in southern Nye County, Nevada. In: Nevada desert ecology. Great Basin Naturalist Memoirs No. 4. Provo, UT: Brigham Young University: 4-23. 
2. 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. 
3. Banner, Roger E. 1992. Vegetation types of Utah. Journal of Range Management. 14(2): 109-114. 
4. Belcher, Earl. 1985. Handbook on seeds of browse-shrubs and forbs. Tech. Publ. R8-TP8. Atlanta, GA: U.S. Department of Agriculture, Forest Service, Southern Region. 246 p. In cooperation with: Association of Official Seed Analysts. 
5. 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. 
6. Blackburn, Wilbert H.; Eckert, Richard E., Jr.; Tueller, Paul T. 1969. Vegetation and soils of the Cow Creek Watershed. R-49. Reno, NV: University of Nevada, Agricultural Experiment Station. 77 p. In cooperation with: U.S. Department of the Interior, Bureau of Land Management. 
7. Blackburn, Wilbert H.; Tueller, Paul T.; Eckert, Richard E., Jr. 1969. Vegetation and soils of the Churchill Canyon Watershed. R-45. Reno, NV: University of Nevada, Agricultural Experiment Station. 155 p. In cooperation with: U.S. Department of the Interior, Bureau of Land Management. 
8. Burkhardt, Wayne J.; Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology. 57: 472-484. 
9. Chambers, Jeanne C.; Norton, Brien E. 1993. Effects of grazing and drought on population dynamics of salt desert species on the Desert Experimental Range, Utah. Journal of Arid Environments. 24: 261-275. 
10. Collins, Ellen I. 1984. Preliminary classification of Wyoming plant communities. Cheyenne, WY: Wyoming Natural Heritage Program/The Nature Conservancy. 42 p. 
11. Cook, C. Wayne; Harris, Lorin E. 1968. Nutritive value of seasonal ranges. Bulletin 472. Logan, UT: Utah State University, Agricultural Experiment Station. 55 p. 
12. Cronquist, Arthur; Holmgren, Arthur H.; Holmgren, Noel H.; Reveal, James L.; Holmgren, Patricia K. 1994. Intermountain flora: Vascular plants of the Intermountain West, U.S.A. Vol. 5: Asterales. New York: The New York Botanical Garden. 496 p. 
13. Deblinger, Robert D. 1988. Ecology and behavior of pronghorn in the Red Desert, Wyoming, with reference to energy development. Fort Collins, CO: Colorado State University. 227 p. Dissertation. 
14. Deblinger, Robert D.; Alldredge, A. William. 1991. Influence of free water on pronghorn distribution in a sagebrush/steppe grassland. Wildlife Society Bulletin. 19(3): 321-326. 
15. 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. 
16. Dorn, Robert D. 1984. Vascular plants of Montana. Cheyenne, WY: Mountain West Publishing. 276 p. 
17. Everett, Richard L.; Meeuwig, Richard O.; Robertson, Joseph H. 1978. Propagation of Nevada shrubs by stem cuttings. Journal of Range Management. 31(6): 426-429. 
18. Everett, Richard L.; Tueller, Paul T.; Davis, J. Barry; Brunner, Allen D. 1980. Plant phenology in galleta-shadscale and galleta-sagebrush associations. Journal of Range Management. 33(6): 446-450. 
19. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
20. Fautin, Reed W. 1946. Biotic communities of the northern desert shrub biome in western Utah. Ecological Monographs. 16: 252-310. 
21. Flora of North America Association. 2009. Flora of North America: The flora, [Online]. Flora of North America Association (Producer). Available: http://www.fna.org/FNA. 
22. 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. 
23. 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. 
24. 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. 
25. Green, Lisle R.; Sharp, Lee A.; Cook, C. Wayne; Harris, Lorin E. 1951. Utilization of winter range forage by sheep. Journal of Range Management. 4: 233-241. 
26. Gullion, Gordon W. 1964. Wildlife uses of Nevada plants. Contributions toward a flora of Nevada: No. 49. CR-24-64. Beltsville, MD: U.S. Department of Agriculture, Agricultural Research Service, Crops Research Division; Washington, DC: U.S. National Arboretum, Herbaium. 170 p. 
27. Harrington, H. D. 1964. Manual of the plants of Colorado. 2nd ed. Chicago, IL: The Swallow Press, Inc. 666 p. 
28. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. 
29. Hutchings, Selar S. 1954. Managing winter sheep range for greater profit. Farmers' Bulletin No. 2067. Washington, DC: U.S. Department of Agriculture. 46 p. 
30. Institute for Land Rehabilitation. 1979. Selection, propagation, and field establishment of native plant species on disturbed arid lands. Bulletin 500. Logan, UT: Utah State University, Agricultural Experiment Station. 49 p. 
31. Johnson, Kendall L., ed. 1978. Wyoming shrublands: Proceedings, 7th Wyoming shrub ecology workshop; 1978 May 31-June 1; Rock Springs, WY. Laramie, WY: University of Wyoming, Agricultural Extension Service. 58 p. 
32. Kartesz, John T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. 1st ed. In: Kartesz, John T.; Meacham, Christopher A. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Chapel Hill, NC: North Carolina Botanical Garden (Producer). In cooperation with: The Nature Conservancy; U.S. Department of Agriculture, Natural Resources Conservation Service; U.S. Department of the Interior, Fish and Wildlife Service. 
33. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2nd ed. Berkeley, CA: University of California Press. 1085 p. 
34. 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. 
35. 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. 
36. McArthur, E. Durant; Blauer, A. Clyde; Plummer, A. Perry; Stevens, Richard. 1979. Characteristics and hybridization of important Intermountain shrubs. III. Sunflower family. Res. Pap. INT-220. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 82 p. 
37. Medin, Dean E.; Welch, Bruce L.; Clary, Warren P. 2000. Bird habitat relationships along a Great Basin elevational gradient. Res. Pap. RMRS-RP-23. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 22 p. 
38. 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. 
39. Moir, William H. 1982. A fire history of the High Chisos, Big Bend National Park, Texas. The Southwestern Naturalist. 27(1): 87-98. 
40. Mucsi, Ilona; Molnar, Joseph; Hohmann, Judit; Redel, Dora. 2001. Cytotoxicities and anti-herpes simplex virus activities of diterpenes isolated from Euphorbia species. Planta Med. 67: 672-674. 
41. 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-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. 
42. Pendleton, Rosemary L.; Pendleton, Burton K.; Harper, Kimball T. 1989. Breeding systems of woody plant species in Utah. In: Wallace, Arthur; McArthur, E. Durant; Haferkamp, Marshall R., comps. Proceedings--symposium on shrub ecophysiology and biotechnology; 1987 June 30 - July 2; Logan, UT. Gen. Tech. Rep. INT-256. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 5-22. 
43. Plummer, A. Perry. 1974. Morphogenesis and management of woody perennials in the United States. In: Plant morphogenesis as the basis for scientific management of range resources: Proceedings of a workshop of the U.S./Australia Rangelands Panel; 1971; Berkley, CA. Misc. Pub. 1271. Washington, DC: U.S. Department of Agriculture, Agricultural Research Service: 72-80. 
44. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
45. Rosentreter, Roger; Jorgensen, Ray. 1986. Restoring winter game ranges in southern Idaho. Tech. Bull. 86-3. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office. 26 p. 
46. Ross, Robert L.; Hunter, Harold E. 1976. Climax vegetation of Montana: Based on soils and climate. Bozeman, MT: U.S. Department of Agriculture, Soil Conservation Service. 64 p. 
47. Rumble, Mark A.; Gobeille, John E. 2004. Avian use of successional cottonwood (Populus deltoides) woodlands along the middle Missouri River. The American Midland Naturalist. 152: 165-177. 
48. Rydberg, P. A. 1916. Artemisia and Artemisiastrum. North American Flora. 34: 244-285. 
49. 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. 
50. Schultz, Brad; McAdoo, Kent. 2002. Common sagebrush in Nevada. Special Publication SP-02-02. Reno, NV: University of Nevada, Cooperative Extension. 9 p. Available: http://www.unce.unr.edu/publications/Spec%%20Pubs/SP-02-02.doc [2002, October 1]. 
51. Shaw, Nancy L.; Monsen, Stephen B. 1990. Use of sagebrush for improvement of wildlife habitat. In: Fisser, Herbert G., ed. Wyoming shrublands: Aspen, sagebrush and wildlife management: Proceedings, 17th Wyoming shrub ecology workshop; 1988 June 21-22; Jackson, WY. Laramie, WY: University of Wyoming, Department of Range Management; Shrub Ecology Workshop: 19-35. 
52. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. 
53. Smith, Arthur D.; Beale, Donald M. 1980. Pronghorn antelope in Utah: some research and observations. Publication No. 80-13. Salt Lake City, UT: Utah Division of Wildlife Resources. 88 p. 
54. Stark, N. 1966. Review of highway planting information appropriate to Nevada. Bulletin No. B-7. Reno, NV: University of Nevada, College of Agriculture, Desert Research Institute. 209 p. In cooperation with: Nevada State Highway Department. 
55. Stickney, Peter F. 1989. Seral origin of species comprising secondary plant succession in Northern Rocky Mountain forests. FEIS workshop: Postfire regeneration. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 10 p. 
56. Stubbendieck, James; Hatch, Stephan L.; Butterfield, Charles H. 1992. North American range plants. 4th ed. Lincoln, NE: University of Nebraska Press. 493 p. 
57. Sutton, Richard F.; Johnson, Craig W. 1974. Landscape plants from Utah's mountains. EC-368. Logan, UT: Utah State University, Cooperative Extension Service. 135 p. 
58. Swetnam, Thomas W.; Baisan, Christopher H.; Caprio, Anthony C.; Brown, Peter M. 1992. Fire history in a Mexican oak-pine woodland and adjacent montane conifer gallery forest in southeastern Arizona. In: Ffolliott, Peter F.; Gottfried, Gerald J.; Bennett, Duane A.; Hernandez C., Victor Manuel; Ortega-Rubio, Alfred; Hamre, R. H., tech. coords. Ecology and management of oak and associated woodlands: perspectives in the southwestern United States and northern Mexico: Proceedings; 1992 April 27-30; Sierra Vista, AZ. Gen. Tech. Rep. RM-218. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 165-173. 
59. U.S. Department of Agriculture, Natural Resources Conservation Service. 2009. PLANTS Database, [Online]. Available: http://plants.usda.gov/. 
60. Van Dersal, William R. 1938. Native woody plants of the United States, their erosion-control and wildlife values. Misc. Publ. No. 303. Washington, DC: U.S. Department of Agriculture. 362 p. 
61. Van Dyne, George M. 1958. Ranges and range plants. Unpublished manuscript on file at: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 290 p. 
62. Vest, E. Dean. 1962. Biotic communities in the Great Salt Lake desert. Ecology and Epizoology Series No. 73. Salt Lake City, UT: University of Utah, Division of Biological Sciences, Institute of Environmental Biological Research. 122 p. 
63. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. 
64. Webb, Robert H.; Steiger, John W.; Newman, Evelyn B. 1988. The response of vegetation to disturbance in Death Valley National Monument, California. U.S. Geological Survey Bulletin 1793. Washington, DC: U.S. Department of the Interior, Geological Survey. 69 p. 
65. 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. 
66. West, Neil E. 1994. Effects of fire on salt-desert shrub rangelands. In: Monsen, Stephen B.; Kitchen, Stanley G., compilers. 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: 71-74. 
67. Wiens, John A.; Rotenberry, John T.; Van Horne, Beatrice. 1987. Habitat occupancy patterns of North American shrubsteppe birds: the effects of spatial scale. Oikos. 48: 132-147. 
68. Wood, Benjamin W. 1966. An ecological life history of budsage in western Utah. Provo, UT: Brigham Young University. 85 p. Thesis. 
69. Wood, Benjamin W.; Brotherson, Jack D. 1986. Ecological adaptation and grazing response of budsage (Artemisia spinescens). In: McArthur, E. Durant; Welch, Bruce L., compilers. Proceedings--symposium on the biology of Artemisia and Chrysothamnus; 1984 July 9-13; Provo, UT. Gen. Tech. Rep. INT-200. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 75-92. 
70. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505.