Index of Species Information
SPECIES: Philadelphus lewisii
SPECIES: Philadelphus lewisii
AUTHORSHIP AND CITATION :
Carey, Jennifer H. 1995. Philadelphus lewisii. In: Fire Effects Information System,
[Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain
Research Station, Fire Sciences Laboratory (Producer). Available:
Philadelphus californicus Benth. 
SCS PLANT CODE :
COMMON NAMES :
Lewis' mock orange
The currently accepted scientific name for Lewis' mock orange is
Philadelphus lewisii Pursh (Hydrangeaceae) [14,15,18]. Recognized
varieties  and subspecies [14,32] are as follows:
Philadelphus lewisii var. angustifolius (Rydb.) Hu
Philadelphus lewisii var. ellipticus Hu
Philadelphus lewisii var. gordonianus (Lindl.) Jepson
Philadelphus lewisii var. helleri (Rydb.) Hu
Philadelphus lewisii var. intermedius (A. Nels.) Hu
Philadelphus lewisii var. lewisii Pursh
Philadelphus lewisii var. oblongifolius Hu
Philadelphus lewisii var. parvifolius Hu
Philadelphus lewisii var. platyphyllus (Rydb.) Hu
Philadelphus lewisii subsp. californicus (Benth.) Munz.
LIFE FORM :
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
DISTRIBUTION AND OCCURRENCE
SPECIES: Philadelphus lewisii
GENERAL DISTRIBUTION :
Lewis' mock orange occurs in the northwestern United States and southern
Canada. It occurs from extreme southern British Columbia south to
California, and east to north and central Idaho, western Montana, and
southwestern Alberta [14,15,34]. Philadelphus lewisii ssp. californicus
occurs from the southern Cascade Range of southwestern Oregon south
through the Sierra Nevada to Tulare County, California [14,32], and P.
l. var. gordonianus occurs in the Coast Ranges and the Cascade Range
from British Columbia south to northern California .
|Distribution of Lewis' mock orange. Map courtesy of USDA, NRCS. 2018. The PLANTS Database.
National Plant Data Team, Greensboro, NC .
FRES21 Ponderosa pine
FRES22 Western white pine
FRES28 Western hardwoods
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
CA ID MT OR WA AB BC
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
2 Cascade Mountains
4 Sierra Mountains
5 Columbia Plateau
8 Northern Rocky Mountains
KUCHLER PLANT ASSOCIATIONS :
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K012 Douglas-fir forest
K013 Cedar-hemlock-pine forest
K014 Grand fir-Douglas-fir forest
K025 Alder-ash forest
K026 Oregon oakwoods
K028 Mosaic of K002 and K026
K034 Montane chaparral
K055 Sagebrush steppe
SAF COVER TYPES :
210 Interior Douglas-fir
212 Western larch
213 Grand fir
219 Limber pine
221 Red alder
222 Black cottonwood-willow
227 Western redcedar-western hemlock
229 Pacific Douglas-fir
230 Douglas-fir-western hemlock
233 Oregon white oak
234 Douglas-fir-tanoak-Pacific madrone
237 Interior ponderosa pine
244 Pacific ponderosa pine-Douglas-fir
245 Pacific ponderosa pine
SRM (RANGELAND) COVER TYPES :
109 Ponderosa pine shrubland
203 Riparian woodland
209 Montane shrubland
HABITAT TYPES AND PLANT COMMUNITIES :
Lewis' mock orange commonly occurs in open coniferous forests and at
forest edges , and is usually associated with other shrubs. In dry
Douglas-fir (Pseudotsuga menziesii) forests on the western slope of the
Cascade Range in Oregon, Lewis' mock orange is positively (significant at
P<0.05) associated with beaked hazelnut (Corylus cornuta), oceanspray
(Holodiscus discolor), poison-oak (Toxicodendron diversilobum), baldhip
rose (Rosa gymnocarpa), and hollyleaved barberry (Mahonia aquifolium).
It reaches its greatest importance in the Douglas-fir/hollyleaved
barberry/disporum (Disporum spp.) community type . Lewis'
mock orange is positively (significant at P<0.05) associated with
ninebark (Physocarpus malvaceus) on talus slopes in western Montana .
Lewis' mock orange occurs in moist draws and riparian areas, especially
in drier regions of the Northwest. In eastern Oregon, Lewis' mock orange
is associated with willows (Salix spp.), alders (Alnus spp.), and
hawthorns (Crataegus spp.) . It occurs with red-osier dogwood
(Cornus sericea) and Saskatoon serviceberry (Amelanchier alnifolia) in
north-central Washington . It occurs with Saskatoon serviceberry and
common chokecherry (Prunus virginiana) on rocky outcrops of the National
Bison Range in western Montana . In Oregon white oak (Quercus
garryana) woodlands in northern California, Lewis' mock orange occurs
along stream channels with oceanspray, cluster rose (R. pisocarpa), pale
serviceberry (A. pallida), and Indian plum (Oemleria cerasiformis). A
Lewis' mock orange/brittle bladderfern (Cystopteris fragilis) community
type has been described .
Lewis' mock orange occurs in seral shrubfields and chaparral communities.
In northern Idaho, Lewis' mock orange is a component of the tall shrub
union that follows logging and burning . In southwestern Oregon,
Philadelphus lewisii ssp. californicus occurs in chaparral dominated by
wedgeleaf ceanothus (Ceanothus cuneatus). Other shrubs present include
skunkbush sumac (Rhus trilobata), yerba santa (Eriodictylon
californicum), chaparral honeysuckle (Lonicera interrupta), Klamath plum
(P. subcordata), hollyleaf redberry (Rhamnus crocea ssp. ilicifolia),
and pale serviceberry .
SPECIES: Philadelphus lewisii
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Lewis' mock orange is of minor importance as a forage species for
livestock . Sampson  considered it poor to useless browse for
cattle and horses. However, Shaw  reports that in riparian areas in
eastern Oregon, Lewis' mock orange is heavily browsed in areas accessible
Lewis' mock orange is a moderately important winter forage species for
deer and elk in the northern Rocky Mountains. In southern British
Columbia, Lewis' mock orange is of moderate importance as a winter forage
species for white-tailed deer and Rocky Mountain elk, and of low
importance to other wild ungulates . In Montana, a 1957 study based
on rumen samples showed that Lewis' mock orange constituted 2 percent of
mule deer diets in the winter and a trace in the summer . In
northern Idaho, use by white-tailed deer was moderate, although a few
individual plants were browsed heavily . Lewis' mock orange seeds
are eaten by quail and squirrels .
Although generally considered of low palatability, Lewis' mock orange is
browsed heavily at times [21,37,42,43]. New sprouts of Lewis'
mock orange are very palatable [1,21,36]. See FIRE MANAGEMENT for
discussion of Lewis' mock orange palatability following fire.
NUTRITIONAL VALUE :
COVER VALUE :
Lewis' mock orange occurs in dense shrub habitats which probably provide
good cover for wildlife. In north-central Washington, Lewis' mock orange
occurs in a riparian cover type which is preferred in both summer and
winter by mule deer for thermal and security cover .
VALUE FOR REHABILITATION OF DISTURBED SITES :
OTHER USES AND VALUES :
Native Americans used the strong, hard branches of Lewis' mock orange for
bows, arrows, combs, tobacco pipes, cradles, and netting shuttles
[17,34]. Lewis' mock orange is cultivated as an ornamental, but
Philadelphus coronarius, a European species, is the most commonly grown
mock orange in the Northwest . Lewis' mock orange is the Idaho state
flower ; it is illegal to collect Lewis' mock orange in Idaho for
export or sale .
OTHER MANAGEMENT CONSIDERATIONS :
Lewis' mock orange is very sensitive to herbicide sprays [2,31]. Effects
of herbicides on Lewis' mock orange are described .
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Philadelphus lewisii
GENERAL BOTANICAL CHARACTERISTICS :
Lewis' mock orange is a native, deciduous, erect to spreading shrub that
grows 3 to 10 feet (1-3 m) tall. The showy flowers occur in clusters of
three to fifteen. The fruit is a four-chambered capsule about 0.24 to
0.39 inch (0.6-1 cm) long . Seeds are about 0.08 inch (0.2 cm)
long. Lewis' mock orange is extremely variable in both vegetative and
floral characteristics .
RAUNKIAER LIFE FORM :
REGENERATION PROCESSES :
Lewis' mock orange reproduces vegetatively and by seed.
Seeds accumulate in the seedbank. Sparsely distributed viable seeds
were collected from the top 2 inches (5 cm) of soil in forested sites in
central Idaho 
Stratification of Lewis' mock orange increases germination. Seeds
stratified for 8 weeks at 41 degrees Fahrenheit (5 deg C) then placed in
a sand medium at 72 to 79 degrees Fahrenheit (22-26 deg C) had 64
percent germination. The germination rate was less than 10 percent for
seeds stratified less than 8 weeks . Germination was 52 percent
when stored at room temperature for 3 years and 39 percent when stored
at 40 degrees Fahrenheit (4 deg C) . Germination was low when seeds
were fully exposed to light or kept in complete darkness .
Fruit development was adversely affected by drought in northern Idaho.
Fruit partially developed, turned brown, and opened, but no viable seed
was produced .
Lewis' mock orange sprouts from the root crown .
SITE CHARACTERISTICS :
Lewis' mock orange occurs on well-drained, moist sites . It grows on
deep, rich alluvial loams to rocky or gravelly loams . Lewis'
mock orange is commonly found on rocky sites, at the base of talus slopes
and cliffs, along streams, and in seasonally moist draws [6,15]. It
is found at talus margins in the Columbia River Basin . It occurs
at seeps, springs, and rocky wet areas in the Crooked River National
Grasslands in central Oregon .
Lewis' mock orange occurs from sea level up to 7,000 feet (2,100 m) in
the Cascade Range [15,43]. Philadelphus lewisii ssp. californicus grows
from 1,000 to 5,000 feet (300-1,500 m) elevation on rocky slopes and in
canyons in the Sierra Nevada . Lewis' mock orange grows best on
northern and eastern exposures .
SUCCESSIONAL STATUS :
Lewis' mock orange is tolerant of moderate shade . It is an early to
mid-seral species  and is often present in seral shrub communities
following logging and burning . Although normally scattered at low
densities , it sometimes occurs in dense, localized stands .
SEASONAL DEVELOPMENT :
Flowering of Lewis' mock orange occurs from May through July. Fruit
matures in late summer and seeds are dispersed in September or October
. The following dates are general ranges drawn from several studies
in northern Idaho. Specific times for several years are reported [8,33].
Development Date of Occurrence
bud burst early April
leaf out late April to early May
leaf growth late April to mid-May
stem elongation early May to late May
flower bloom late June to July
fruit development begins in July
leaf fall late September to late November
SPECIES: Philadelphus lewisii
FIRE ECOLOGY OR ADAPTATIONS :
Lewis' mock orange occurs in both forested environments which frequently
experience fire and on rocky scree slopes which may not burn at all. In
western Montana, Lewis' mock orange occurs in Douglas-fir habitat types
which had historical fire frequencies of 5 to 45 years . The
ability of Lewis' mock orange to sprout after top-kill by fire enables it
to persist in these forests.
FIRE REGIMES :
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".
POSTFIRE REGENERATION STRATEGY :
Tall shrub, adventitious-bud root crown
Ground residual colonizer (on-site, initial community)
SPECIES: Philadelphus lewisii
IMMEDIATE FIRE EFFECT ON PLANT :
Lewis' mock orange is top-killed by fire, but the root crown usually
survives and produces sprouts [10,23,24].
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
PLANT RESPONSE TO FIRE :
Lewis' mock orange sprouts vigorously from the root crown following fire
[10,23,24]. After an April fire on a south-facing slope in
north-central Idaho, Lewis' mock orange increased to prefire densities by
the third postfire growing season .
The following two studies have investigated the sprouting response of
Lewis' mock orange to fire.
Seral brushfields within the grand fir (Abies grandis)/pachistima
(Pachistima myrsinites) habitat type in northern Idaho were burned in
either spring (late March - early April) or fall (October).
Temperatures during the fires ranged from 67 to 78 degrees Fahrenheit
(19-26 deg C), and relative humidities ranged from 25 to 48 percent.
Lewis' mock orange on sites burned in October did not sprout until the
following April. Lewis' mock orange on the spring-burned sites sprouted
4 to 8 weeks after the fire. Twenty completely top-killed Lewis'
mock orange (eleven on the fall burned sites and nine on the spring
burned sites) were measured at the end of the first postfire growing
Fall Fires Spring Fires
Average crown diameter (ft)
prefire 4.7 (143 cm) 4.7 (143 cm)
postfire 2.4 (73 cm) 2.2 (67 cm)
Average crown height (ft)
prefire 8.8 (268 cm) 9.6 (293 cm)
postfire 4.1 (125 cm) 3.7 (113 cm)
No. basal sprouts per plant
prefire 1.5 0.6
postfire 38.0 28.9
Average postfire sprout height (ft) 2.4 (73 cm) 2.1 (64 cm)
A multiple regression equation is presented which relates the number of
postfire basal sprouts to prefire crown height, crown diameter, and
crown volume .
In another study in north-central Idaho, a brushfield was burned three
times at 5-year intervals (31 March 1965, 3 May 1970, and 14 May 1975).
Maximum air temperatures during the fires were 77, 81, and 88 degrees
Fahrenheit (25, 27, and 31 deg C), and relative humidities at 4:00 pm
were 35, 16, and 27 percent, respectively. Leaves on shrubs and
succulent herbaceous growth depressed the fire in 1975. A single Lewis'
mock orange was followed during the study. The plant was dormant during
the first fire, but leaves were beginning to emerge at the time of the
second fire and were completely emerged at the time of the third fire.
With each successive fire, average sprout height decreased. Reduced
growth following the second and third fires may have resulted from the
advanced phenological stage at the time of those fires. Sprout height
and number were measured the first growing season following each fire.
Crown height and diameter were measured during the second postfire
growing season .
No. basal sprouts Average sprout height (ft)
1965 14 2.0 (61 cm)
1970 19 1.5 (46 cm)
1975 16 1.0 (30 cm)
Crown height (ft) Crown diameter (ft)
prefire 7.0 (213 cm) 1.5 (46 cm)
1966 4.0 (122 cm) 2.0 (61 cm)
1971 2.5 (76 cm) 2.0 (61 cm)
1976 2.5 (76 cm) 1.5 (46 cm)
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
FIRE MANAGEMENT CONSIDERATIONS :
Lewis' mock orange palatability increases following fire. After a spring
fire in northern Idaho, utilization of Lewis' mock orange by Rocky
Mountain elk was significantly (p<0.05) greater on recently burned sites
than on adjacent unburned sites .
% of available twigs browsed
1st season 2nd season
Control 1.3 0.6
Burn 36.3 30.0
Allometric equations, which can be used to estimate fuel quantities,
have been developed for Lewis' mock orange. The equations use basal stem
diameter to estimate foliage biomass and total biomass .
References for species: Philadelphus lewisii
1. Asherin, Duane A. 1975. Changes in elk use and available browse production on north Idaho winter ranges following prescribed burning. In: Hieb, S., ed. Proceedings, elk logging-roads symposium; [Date of conference unknown]; Moscow, ID. [Place of publication unknown]: [Publisher unknown]. 122-134. 
2. Balfour, Patty M. 1989. Effects of forest herbicides on some important wildlife forage species. Victoria, BC: British Columbia Ministry of Forests, Research Branch. 58 p. 
3. 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. 
4. Blower, Dan. 1982. Key winter forage plants for B.C. ungulates. Victoria, BC: British Columbia Ministry of the Environment, Terrestrial Studies Branch. 
5. Brown, J. K. 1976. Estimating shrub biomass from basal stem diameters. Canadian Journal of Forest Research. 6: 153-358. 
6. Carson, Robert G.; Peek, James M. 1987. Mule deer habitat selection patterns in northcentral Washington. Journal of Wildlife Management. 51(1): 46-51. 
7. Detling, LeRoy E. 1961. The chaparral formation of southwestern Oregon, with considerations of its postglacial history. Ecology. 42(2): 348-357. 
8. Wagonfehr, Bob. 1987. Chaparral and the Tonto land management plan. In: Wagner, Michael R., ed. Challenges and opportunities in chaparral management: Proceedings of the Southwestern Society of American Foresters annual fall meeting; 1986 November 12-14; Prescott, AZ. SAF Publication No. SAF 87.10. Flagstaff, AZ: Northern Arizona State University and the San Francisco Peaks Chapter of the Society of American Foresters: 14. 
9. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
10. Fischer, William C.; Bradley, Anne F. 1987. Fire ecology of western Montana forest habitat types. Gen. Tech. Rep. INT-223. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 95 p. 
11. Franklin, Jerry F.; Dyrness, C. T. 1973. Natural vegetation of Oregon and Washington. Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 417 p. 
12. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
13. Heady, Harold F., ed. 1988. The Vale rangeland rehabilitation program: an evaluation. Resour. Bull. PNW-RB-157. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; U.S. Department of the Interior, Bureau of Land Management. 151 p. 
14. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. 
15. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. 
16. Hopkins, William E.; Kovalchik, Bernard L. 1983. Plant associations of the Crooked River National Grassland. R6 Ecol 133-1983. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 98 p. 
17. Idaho State Department of Commerce and Development. [n.d.]. Idaho wild flowers. Boise, ID: Idaho State Department of Commerce and Development. Pamphlet. 10 p. 
18. Kartesz, John T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. Volume II--thesaurus. 2nd ed. Portland, OR: Timber Press. 816 p. 
19. Kramer, Neal B.; Johnson, Frederic D. 1987. Mature forest seed banks of three habitat types in central Idaho. Canadian Journal of Botany. 65: 1961-1966. 
20. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. 
21. Leege, Thomas A. 1969. Burning seral brush ranges for big game in northern Idaho. Transactions, North American Wildlife and Natural Resources Conference. 34: 429-438. 
22. Leege, Thomas A. 1978. Changes in browse production after burning vs. slashing and burning on the four cardinal aspects--Polar Ridge. Job Completion Report No. W-160-R. Elk ecology: Range rehabilitation by spring burning: July 1, 1967 to June 30, 1978. Boise, ID: Idaho Department of Fish & Game. 20 p. 
23. Leege, Thomas A. 1979. Effects of repeated prescribed burns on northern Idaho elk browse. Northwest Science. 53(2): 107-113. 
24. Leege, Thomas A.; Hickey, William O. 1971. Sprouting of northern Idaho shrubs after prescribed burning. Journal of Wildlife Management. 35(3): 508-515. 
25. McCune, Bruce. 1977. Vegetation development on a low elevation talus slope in western Montana. Northwest Science. 51(3): 198-207. 
26. Means, Joseph Earl. 1980. Dry coniferous forests in the western Oregon Cascades. Corvallis, OR: Oregon State University. 264 p. Dissertation. 
27. Miller, Daniel L.; Kidd, Frank A. 1983. Shrub control in the Inland Northwest--a summary of herbicide test results. Forestry Research Note RN-83-4. Lewiston, ID: Potlatch Corporation. 49 p. 
28. Mirov, N. T.; Kraebel, C. J. 1937. Collecting and propagating the seeds of California wild plants. Res. Note No. 18. Berkeley, CA: U.S. Department of Agriculture, Forest Service, California Forest and Range Experiment Station. 27 p. 
29. Morris, Melvin S.; Schwartz, John E. 1957. Mule deer and elk food habits on the National Bison Range. Journal of Wildlife Management. 21(2): 189-193. 
30. Moseley, Robert K. 1992. Rare plant conservation in Idaho. Journal of the Idaho Academy of Science. 28(2): 82-93. 
31. Mueggler, Walter F. 1966. Herbicide treatment of browse on a big-game winter range in northern Idaho. Journal of Wildlife Management. 30(1): 141-151. 
32. Munz, Philip A. 1973. A California flora and supplement. Berkeley, CA: University of California Press. 1905 p. 
33. Orme, Mark L.; Leege, Thomas A. 1980. Phenology of shrubs on a north Idaho elk range. Northwest Science. 54(3): 187-198. 
34. Pojar, Jim; MacKinnon, Andy, eds. 1994. Plants of the Pacific Northwest coast: Washington, Oregon, British Columbia and Alaska. Redmond, WA: Lone Pine Publishing. 526 p. 
35. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
36. Sampson, Arthur W.; Jespersen, Beryl S. 1963. California range brushlands and browse plants. Berkeley, CA: University of California, Division of Agricultural Sciences, California Agricultural Experiment Station, Extension Service. 162 p. 
37. Shaw, Nancy L. 1992. Recruitment and growth of Pacific willow and sandbar willow seedlings in response to season and intensity of cattle grazing. In: Clary, Warren P.; McArthur, E. Durant; Bedunah, Don; Wambolt, Carl L., compilers. Proceedings--symposium on ecology and management of riparian shrub communities; 1991 May 29-31; Sun Valley, ID. Gen. Tech. Rep. INT-289. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 130-137. 
38. Steele, Robert; Geier-Hayes, Kathleen. 1989. The Douglas-fir/ninebark habitat type in central Idaho: succession and management. Gen. Tech. Rep. INT-252. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 65 p. 
39. Stickney, Peter F. 1974. Philadelphus lewisii Pursh. Lewis mockorange. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United States. Agriculture Handbook No. 450. Washington, DC: U.S. Department of Agriculture, Forest Service: 580-581. 
40. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 10 p. 
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42. Thilenius, John Frederick. 1960. Forage utilization by cattle and white-tailed deer on a northern Idaho forest range. Moscow, ID: University of Idaho. 87 p. Thesis. 
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44. USDA Natural Resources Conservation Service. 2018. PLANTS Database, [Online]. U.S. Department of Agriculture, Natural Resources Conservation Service (Producer). Available: https://plants.usda.gov/. 
45. U.S. Department of the Interior, National Biological Survey. [n.d.]. NP Flora [Data base]. Davis, CA: U.S. Department of the Interior, National Biological Survey. 
46. Van Dersal, William R. 1938. Native woody plants of the United States, their erosion-control and wildlife values. Washington, DC: U.S. Department of Agriculture. 362 p. 
47. Wilkins, Bruce T. 1957. Range use, food habits, and agricultural relationships of the mule deer, Bridger Mountains, Montana. Journal of Wildlife Management. 21(2): 159-169. 
48. Wittinger, W. T.; Pengelly, W. L.; Irwin, L. L.; Peek, J. M. 1977. A 20-year record of shrub succession in logged areas in the cedar- hemlock zone of northern Idaho. Northwest Science. 51(3): 161-171. 
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