Introductory
SPECIES: Ambrosia deltoidea | Triangle Bursage 



ABBREVIATION : 
AMBDEL

SYNONYMS : 
   Franseria deltoidea Torr. [13]


SCS PLANT CODE : 
   AMDE4


COMMON NAMES : 
   triangle bursage


TAXONOMY : 
The currently accepted scientfic name for triangle bursage is Ambrosia
deltoidea (Torr.) Payne [24].  It is a member of the aster family
(Asteraceae).  There are no recognized subspecies, varieties, or forms.
 


LIFE FORM : 
Shrub

FEDERAL LEGAL STATUS : 
No special status

OTHER STATUS : 
NO-ENTRY


COMPILED BY AND DATE : 
Sara Lynn Korthuis, September 1988


LAST REVISED BY AND DATE : 
K. Anna Marshall, October 1994


AUTHORSHIP AND CITATION : 
Marshall, K. Anna. 1994. Korthuis, Sara Lynn. 1988. Ambrosia deltoidea.
In: Remainder of Citation

DISTRIBUTION AND OCCURRENCE
SPECIES: Ambrosia deltoidea | Triangle Bursage 



GENERAL DISTRIBUTION : 
Triangle bursage occurs throughout much of the Sonoran Desert.  It
extends southward from southwestern Arizona into Sonora and Baja
California, Mexico [2,3,16,24,27].


ECOSYSTEMS : 
   FRES30  Desert shrub
   FRES40  Desert grasslands


STATES : 
     AZ  MEXICO


ADMINISTRATIVE UNITS : 
     ORPI  SAGU


BLM PHYSIOGRAPHIC REGIONS : 
    7  Lower Basin and Range
   12  Colorado Plateau


KUCHLER PLANT ASSOCIATIONS : 
   K042  Creosotebush - bursage
   K043  Paloverde - cactus shrub


SAF COVER TYPES : 
   242 Mesquite


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Triangle bursage is a dominant or codominant member of the Arizona
Upland Subdivision of the Sonoran Desert [5,8,16].  Although it mostly
occurs in the ecotone between upper and lower bajadas, it also grows on
upper bajadas, in lowland communities dominated by creosotebush (Larrea
tridentata), and in desert grassland communities [3,4,10,16,33].

In the ecotone between upper and lower bajadas, characterized by steep,
gravelly slopes, triangle bursage occurs in a paloverde (Cercidium
spp.)-cacti-mixed scrub series and the desert scrub community type.
Associated species include yellow paloverde (C. microphyllum), saguaro
(Carnegiea gigantea), condalia (Condalia lycioides), ocotillo
(Fouquieria splendens), jatropha (Jatropha cardiophylla), and prickly
pear (Opuntia spp.) [3,8,16].

On upper bajadas, triangle bursage is codominant with jojoba (Simmondsia
chinensis), yellow paloverde, mesquite (Prosopis juliflora), and
ironwood (Olneya tesota) [4].

In desert grassland communities that have been overgrazed, triangle
bursage can be found among other invading perennial shrubs including
corvillea (Corvillea tridentata), yellow paloverde, jojoba, ocotillo,
wolfberry (Lycium spp.), acacia (Acacia spp.), canotia (Canotia
holacantha), velvet mesquite (Prosopis juliflora var. velutina), and
saguaro [33].

Publications listing triangle bursage as a dominant or codominant
species include:

The Natural Vegetation of Arizona [19]
Sonoran Desertscrub [32]
Vegetation of the Santa Catalina Mountains: community types and
  dynamics [20]

Other species associated with triangle bursage but not previously
mentioned are brittle bush (Encelia farinosa), false-mesquite
(Calliandra eriophylla), Berlandier wolfberry (Lycium berlandieri),
hedgehog cactus (Echinocereus engelmanii), ferocactus (Ferocactus
acanthodes), and white ratany (Krameria grayi).

  

VALUE AND USE
SPECIES: Ambrosia deltoidea | Triangle Bursage 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
According to Stubbendieck and others [28], triangle bursage is
worthless as forage for livestock.


PALATABILITY : 
Triangle bursage is unpalatable [31].  McAuliffe and others [43] report that
it is highly unpalatable to mammalian herbivores.


NUTRITIONAL VALUE : 
NO-ENTRY


COVER VALUE : 
NO-ENTRY


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Triangle bursage may stabilize critical areas such as surface-mined
lands in arid regions.  It can be established by direct seeding or with
containerized plants [30].


OTHER USES AND VALUES : 
The paloverde/triangle bursage community is an aesthetically attractive
plant community, and it is often preserved as a form of landscaping when
urban development occurs [20].


MANAGEMENT CONSIDERATIONS : 
Domestic grazing has caused a decrease in grasses and subsequent lack of
fuel for burning in the Sonoran Desert.  As a result, bursage (Ambrosia
spp.) has increased in the Sonoran Desert [2].  During a 30-year period
of protection from grazing, triangle bursage decreased while perennial
grasses and palatable shrubs increased [1].  Hessing and Johnson [11]
found that removing woody plants, including triangle bursage,
contributed to greater herb growth.

Because of its dense, low-lying canopy, triangle bursage may protect the
seedlings of other species from herbivory.  McAuliffe [17] found that
rabbits consumed a greater proportion of seedlings in the open than
under triangle bursage.

Triangle bursage is the principal nurse plant for saguaro at Organ Pipe
National Monument.  Its shade reduces maximum soil surface temperatures,
and it also provides a microhabitat with elevated soil nitrogen levels
[9].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ambrosia deltoidea | Triangle Bursage 



GENERAL BOTANICAL CHARACTERISTICS : 
Triangle bursage is a native, drought-deciduous, microphyllous shrub
growing up to 1.65 feet (50 cm) tall [24, 29].  Innumerable slender and
brittle branches spring up from the base forming a compact, roughly
hemispherical crown [27, 35].  Mature triangle bursage crowns contain
many dead branches which are shed only as a result of weathering [27].

The branches and young leaves of triangle bursage are tomentulose and
resinous.  Leaves become glabrous above with age.  Leaf length is 0.6 to
0.8 inches (1.5-2 cm) or smaller [24,27].

Staminate heads are borne terminally.  Two-flowered, pistillate
involucres are clustered below the staminate spikes or on lateral
branches.  They produce globose, spiny achenes [24,27].

Triangle bursage possesses one long taproot with well-developed laterals
[35].  Triangle bursage roots are slender, brittle, and longitudinally
ridged with cork [6].  They are confined to the soil above the caliche
hardpan--about 8 to 16 inches (20-40 cm) deep [6,35].  Besides roots
arising from the main root, Cannon [6] found 50 adventitious roots about
0.12 inches (3 mm) in diameter which arose from the root crown, growing
horizontally.  Filamentous rootlets formed on many roots of triangle
bursage after the soil had been moistened by rains, but such rootlets
were short lived [6].

Triangle bursage is relatively short lived for a desert shrub.  It has
an observed longevity of about 50 years [10,27].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Triangle bursage reproduces sexually.  Seed is produced abundantly, and
seedlings establish in open space.  In the Sonoran Desert, the relative
abundance of triangle bursage seedlings was some 45 times the density of
mature triangle bursage plants.  The density of mature triangle bursage
was similar to that of mature creosotebush, but 1,001 triangle bursage
seedlings were counted while only 124 creosotebush seedlings were found
[17].

Triangle bursage seeds are spiny and are probably dispersed by mammals.

One study reports that triangle bursage has very limited ability to
sprout after top-kill [18].  No other research describes the ability of
triangle bursage to sprout.

Triangle bursage reproduces from cuttings with the application of auxin
[15].


SITE CHARACTERISTICS : 
Triangle bursage commonly grows in open spaces [17] on pediments, upper
bajada surfaces, and basin floors on a variety of substrates including
volcanic, granitic, metamorphic, alluvial, and caliche soils.  There was
no significant difference in cover of triangle bursage among volcanic,
granitic, metamorphic, and alluvial substrates [21].

Triangle bursage is a frequent dominant on gravel outwashes, bajadas,
and the ecotone between upper and lower bajadas [3,17,35].  Triangle
bursage occurs almost entirely on very coarse soils that are relatively
uniform in composition with little differentiation into horizons
[3,14,15], although it occurs rarely on sand [27].  Precipitation
percolates rapidly through the soil and drains quickly away along the
underlying caliche layer [1,35].

Rainfall averages 4 to 12 inches (100-300 mm) annually with a bimodal
distribution [16,25].  Temperatures at Organ Pipe National Monument and
elsewhere in the Sonoran Desert fluctuate daily and seasonally.  The
mean frost frequency at the monument from 1956 to 1985 was 17 frosts per
year (standard deviation=7, range=5-34) [21].

Parker [22] studied the soil characteristics of sites dominated by
triangle bursage at Organ Pipe National Monument.  Overall, triangle
bursage was most abundant on flat terrain, but its cover was reduced on
the lower bajadas and in the western portion of the Monument where pH
was relatively high [22].  In the Ajo Mountains on south-facing slopes,
sites had low pH and high available magnesium.  In the Blanco Mountains,
Senita Basin, and Quitobaquito Hills, available magnesium was low.  In
the Bates Mountains, Puerto Blanco Mountains, lower elevations of the
Ajo Mountains, and flats in Senita Basin, triangle bursage grew on
north-facing slopes in volcanic soil.  In the Sonoyta Mountains,
triangle bursage grew on northwest- to northeast-facing slopes.  Leitner
[14] found that triangle bursage preferred the cooler, more humid
conditions of north-facing slopes at Punta Cirio, Sonora, Mexico,
although it occurred on both north- and south-facing slopes.  Triangle
bursage grows from 1,000 to 3,000 feet (300-900 m) [13].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Triangle bursage is often the first plant to occupy an open area.
Recruitment of other species rarely occurs in the open.  Once
established, triangle bursage acts as a nurse plant for other species,
providing improved microhabitat and protection from herbivory [17,9].

Most mature triangle bursage plants have an associated perennial.
Eighty-two out of 103 triangle bursage plants lacking associated
perennials were small (and presumably young)--2 inches (5 cm) or less in
root crown diameter.  Only 2 of 101 triangle bursage plants that had
other perennials associated with them had basal diameters of 2 inches (5
cm) or less [17].

Succession in the desert is difficult to characterize.  Although changes
in relative abundances of species may occur, plants rarely disappear
from the ecosystem altogether because severe disturbance is usually
lacking [17].  McAuliffe [17] described changes in desert vegetation in
terms of community dynamics instead of succession.  For instance, in
communities codominated by triangle bursage, triangle bursage colonizes
open space and acts as a nurse plant for other perennial shrubs.  Some
larger, presumably older individuals within the population bear no
evidence of former associations with triangle bursage, probably because
they have outlived it.  Triangle bursage continues to colonize other
open space.  Relative abundance of species may be altered, but triangle
bursage presence is maintained [17].

Triangle bursage is known to establish on overgrazed desert grasslands.
Tueller [31] suggested that partial or complete protection from grazing
on triangle bursage-invaded rangeland will promote secondary succession.
Secondary succession results in the establishment of climax grasses and
palatable shrubs and a decrease in unpalatable shrubs such as triangle
bursage.

When growing among creosotebush and jumping cholla (Opuntia fulgida),
triangle bursage occupies a distinct root zone so interspecific
competition is minimized [35].  In one study, no roots of neighboring
plants grew near triangle bursage roots [6].


SEASONAL DEVELOPMENT : 
Most new leaves on triangle bursage develop and mature during the winter
and early spring [29].  Triangle bursage flowers from February to July
[33].  Seeds are produced after both summer and winter rains [27].

FIRE ECOLOGY
SPECIES: Ambrosia deltoidea | Triangle Bursage 



FIRE ECOLOGY OR ADAPTATIONS : 
Because triangle bursage establishes in open spaces, it survives fires
that burn with a mosaic pattern [26].

Although triangle bursage seedlings establish after fire, the literature
does not mention whether the seed originates on- or off-site.

Fires occur frequently in the desert grassland at the eastern margin of
the Sonoran Desert.  Fires in the desert proper, however, are infrequent
and generally of low severity because production of annual and perennial
herbs seldom provides a fuel load capable of sustaining fire [18].
Fires occur occasionally in the Sonoran Desert, mostly in the Arizona
Upland where the biannual rainfall produces relatively lush rangeland
[23,26].  Following a moist year, the desert floor is covered with
sufficient annual plant fuel and litter to carry a fire [23].  When
winter annuals thrive, fire is more likely [2,17].  Exotic annuals may
be more productive than native species and fuel more frequent, more
severe fires [2].




POSTFIRE REGENERATION STRATEGY : 
NO-ENTRY

FIRE EFFECTS
SPECIES: Ambrosia deltoidea | Triangle Bursage 



IMMEDIATE FIRE EFFECT ON PLANT : 
Triangle bursage is usually top-killed or killed by fire [18,26].



DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Burning generally decreases bursage (Ambrosia spp.) cover
[2,7,18,26,34].

It is not clear whether top-killed triangle bursage sprout after fire.
One study found 1 percent of top-killed triangle bursage sprouting 4
years after a fire [18].  No other research describes the ability of
triangle bursage to sprout.

Triangle bursage produces a large amount of seed, and seedlings
establish after fire.  Following fires that occurred in 1974 in
south-central Arizona, no triangle bursage sprouted, but several
survived in unburned patches.  Density of triangle bursage in postfire
year 1 was 275 plants per 1,500 square meters; 3 to 4 years later,
density was 49 plants per 1,500 square meters.  Eighty-two percent of
all seedlings were triangle bursage [26].

Desert fires reduce perennial plant cover, often for several years [26].
In an Upper Sonoran Desert site on the Tonto National Forest, prefire
coverage of perennial plants, including triangle bursage, was 30.7
percent.  Perennial cover immediately after fire was 9.3 percent.  The
physical characteristics of the study site, including soil surface
albedo, microsite maximum and minimum temperatures, and soil water
repellency were not greatly altered [23].

The killed portion of a woody, desert plant such as triangle bursage
usually represents many years of growth.  Repeated fires, even when they
do not kill woody taxa outright, keep them in a juvenile, nonfruiting
stage [12].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
A low-severity lightning fire occured in late June of 1979 in the
Sonoran Desert near Florence, Arizona.  The prefire vegetative community
was typical of the Arizona Upland Subdivision of the Sonoran Desert.
The dominant species were triangle bursage, yellow paloverde,
creosotebush, saguaro, buckhorn cholla (Opuntia acanthocarpa), hedgehog
(Echinocereus fasciculatus), barrel cactus (Ferocactus wislizenii), and
prickly pear (Opuntia phaeacantha).  Small patches of vegetation were
skipped throughout the burn.  With the exception of these skips, nearly
all trees and shrubs were completely top-killed [18].

The density of triangle bursage 19 months after the fire was 540 plants
per hectare, compared to 6,790 plants per hectare in the unburned control
area.  Percent cover of triangle bursage was 0.7 percent in burned areas
and 7.4 percent in control areas.  Ninety-three percent of all triangle
bursage plants in burned areas were top-killed; overall mortality of
triangle bursage was 92 percent.  By 1981, only 1 percent of top-killed
triangle bursage plants were sprouting [18].


FIRE MANAGEMENT CONSIDERATIONS : 
McLaughlin and Bowers [18] hypothesized that two consecutive wet winters
may be required for the development of a fuel load adequate to sustain
fire in the Sonoran Desert.  The first wet winter would result in higher
production of annuals and the addition of large numbers of seeds to the
soil.  The second wet winter would facilitate sprouting of the increased
number of seeds and production of enough annuals to sustain fire.

Native American Hohokam farmers (A.D. 11150-1350) cleared fields,
ditches, and broad patches of the desert by fire.  Hohokam farmers found
that burning could increase the variety of plants available to be
gathered and mammals to be hunted.  The fossil record shows about 40
percent bursage (Ambrosia spp.) pollen in Hohokam times compared with 74
percent in modern times [2].

Desert fires may create potential soil stability problems [23].

FIRE CASE STUDIES
SPECIES: Ambrosia deltoidea | Triangle Bursage 



CASE NAME : 
Bull Dog Canyon/Arizona Prescribed Fire


CREFERENCES : 
Cave, G. H., III. 1982. [7]
Patten, Duncan T.; Cave, George H. 1984 [23]


SEASON/SEVERITY CLASSIFICATION : 
summer/low-severity


STUDY LOCATION : 
The study was located in Bulldog Canyon in Tonto National Forest,
Arizona, at 33 degrees 15 minutes north latitude and 111 degrees 33
minutes west longitude.


PREFIRE VEGETATIVE COMMUNITY : 
The prefire vegetative community was typical of the Upper Sonoran Desert
paloverde-cactus-shrub association (Cercidium spp.-Opuntia spp. and
Carnegiea gigantea-Ambrosia spp.).  Plants occupied about one-third of
the total ground cover.  Triangle bursage (A. deltoidea) occupied about
15 percent of the total ground cover.  Annual forbs and grasses in this
association are abundant after winter and heavy summer rains, providing
enough fuel to carry a fire.


TARGET SPECIES PHENOLOGICAL STATE : 
At the time of the fire, triangle bursage would have been flowering
and/or fruiting.


SITE DESCRIPTION : 
Topography is flat except for one small, dry wash bisecting
the site.  The soil is composed of sandy loam argids with a desert
pavement surface.  Elevation at the site is 1,485 feet (450 m).

The burn site is adjacent to an area burned by wildfire on April 26,
1980.  The 1980 wildfire may have been more severe since both 1979 and
1980 were years of above average precipitation, and the standing
herbaceous vegetation was probably relatively lush.  The study compares
the prescribed fire and the wildfire sites.


FIRE DESCRIPTION : 
The fire was ignited on June 12, 1981.  Conditions were typical for
summer months in the Upper Sonoran Desert.  Air temperatures ranged from
104 degrees Fahrenheit (40 deg C) in the shade to 132.8 degrees
Fahrenheit (56 deg C) 0.4 inches (1 cm) above the unshaded soil surface.
Relative humidity remained at 29 percent during the fire.  Mean air
movement for the duration of the fire was low at 0.001 meters per
second.  Mean wind velocity for gusts was 2.75 meters per second.  Mean
soil moisture percent in the upper 2 inches (5 cm) of soil was 0.61
percent in open areas and 0.80 percent in shaded areas.  Litter fuel
averaged 143.3 grams per square meter.


FIRE EFFECTS ON TARGET SPECIES : 
In 1981, 1 year after the wildfire and immediately following the
controlled burning, the density of triangle bursage was greater on the
wildfire site than on the prescribed fire site, mainly because of the
establishment of triangle bursage seedlings on the wildfire site.
Postfire cover measurements were nearly the same.

Triangle bursage density was reduced by 82 percent on the prescribed
fire site immediately after the controlled burning.  The prefire density
of triangle bursage on the prescribed fire site was 6,275 plants per
hectare.  Immediately after the controlled burning, triangle bursage
density was 1,141 plants per hectare.  One year later, triangle bursage
density had not changed significantly.


FIRE MANAGEMENT IMPLICATIONS : 
NO-ENTRY

REFERENCES
SPECIES: Ambrosia deltoidea | Triangle Bursage 



REFERENCES : 

 .  Blydenstein, John; Hungerford, C. Roger; Day, Gerald I.; Humphrey, R.
       1957. Effect of domestic livestock exclusion on vegetation in the
       Sonoran Desert. Ecology. 38(3): 522-526.  [4570]

 .  Bohrer, Vorsila L. 1992. New life from ashes II: A tale of burnt brush.
       Desert Plants. 10(3): 122-125.  [18805]

 .  Bowers, Michael A. 1988. Plant associations on a Sonoran Desert bajada:
       geographical correlates and evolutionary source pools. Vegetatio. 74:
       107-112.  [4408]

 .  Brooks, William H. 1978. Jojoba--a North American desert shrub; its
       ecology, possible commercialization, & potential as an introd. into
       other arid regions. Journal of Arid Environments. 1: 227-236.  [5162]

 .  Burgess, Tony L.; Bowers, Janice E.; Turner, Raymond M. 1991. Exotic
       plants at the Desert Laboratory, Tucson, Arizona. Madrono. 38(2):
       96-114.  [15362]

 .  Cannon, William Austin. 1911. The root habits of desert plants.
       Washington, DC: The Carnegie Institution of Washington. 96 p.  [5003]

 .  Cave, George Harold, III. 1982. Ecological effects of fire in the upper
       Sonoran Desert. Tempe, AZ: Arizona State University. 124 p. Thesis. 
       [12295]

 .  Daniel, Thomas F.; Butterwick, Mary L. 1992. Flora of the South
       Mountains of south-central Arizona. Desert Plants. 10(3): 99-119. 
       [19896]

 .  Franco, A. C.; Nobel, P. S. 1989. Effect of nurse plants on the
       microhabit and growth of cacti. Journal of Ecology. 77: 870-886.  [9766]

.  Goldberg, Deborah E.; Turner, Raymond M. 1986. Vegetation change and
       plant demography in permanent plots in the Sonoran Desert. Ecology.
       67(3): 695-712.  [4410]

.  Hessing, M. B.; Johnson, C. D. 1982. Disturbance and revegetation of
       Sonoran Desert vegetation in an Arizona powerline corridor. Journal of
       Range Management. 35(2): 254-258.  [4320]

.  Humphrey, Robert R. 1963. The role of fire in the desert and desert
       grassland areas of Arizona. In: Proceedings, 2nd annual Tall Timbers
       fire ecology conference; 1963 March 14-15; Tallahassee, FL. Tallahassee,
       FL: Tall Timbers Research Station: 45-61.  [19000]

.  Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock,
       Elizabeth. 1960. Arizona flora. 2d ed. Berkeley, CA: University of
       California Press. 1085 p.  [6563]

.  Leitner, Lawrence A. 1987. Plant communities of a large arroyo at Punta
       Cirio, Sonora. Southwestern Naturalist. 32(1): 21-28.  [1439]

.  Losher, Lee. 1993. Propagation, revegetation program underway Organ Pipe
       National Monument. Restoration & Management Notes. 11(2): 166-167. 
       [22790]

.  MacMahon, James A. 1988. Warm deserts. In: Barbour, Michael G.;
       Billings, William Dwight, eds. North American terrestrial vegetation.
       Cambridge; New York: Cambridge University Press: 231-264.  [19547]

.  McAuliffe, Joseph R. 1988. Markovian dynamics of simple and complex
       desert plant communities. American Naturalist. 131(4): 459-490.  [6744]

.  McLaughlin, Steven P.; Bowers, Janice E. 1982. Effects of wildfire on a
       Sonoran Desert plant community. Ecology. 63(1): 246-248.  [1619]

.  Nichol, A. A. [revisions by Phillips, W. S.]. 1952. The natural
       vegetation of Arizona. Tech. Bull. 68 [revision]. Tucson, AZ: University
       of Arizona, Agricultural Experiment Station: 189-230.  [3928]

.  Niering, William A.; Lowe, Charles H. 1984. Vegetation of the Santa
       Catalina Mountains: community types and dynamics. Vegetatio. 58: 3-28. 
       [12037]

.  Parker, Kathleen C. 1988. Environmental relationships and vegetation
       associates of columnar cacti in the northern Sonoran Desert. Vegetatio.
       78: 125-140.  [6953]

.  Parker, Kathleen C. 1991. Topography, substrate, and vegetation patterns
       in the northern Sonoran Desert. Journal of Biogeography. 18: 151-163. 
       [14979]

.  Patten, Duncan T.; Cave, George H. 1984. Fire temperatures and physical
       characteristics of a controlled burn in the upper Sonoran Desert.
       Journal of Range Management. 37(3): 277-280.  [181]

.  Payne, Willard W. 1964. A re-evaluation of the genus Ambrosia
       (Compositae). Journal of the Arnold Arboretum. 45(4): 401-438.  [5063]

.  Robinett, Dan. 1990. Tohono O'odham range history. Rangelands. 12(6):
       296-300.  [14968]

.  Rogers, Garry F.; Steele, Jeff. 1980. Sonoran Desert fire ecology. In:
       Stokes, Marvin A.; Dieterich, John H., technical coordinators.
       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: 15-19.  [16036]

.  Shreve, Forrest; Wiggins, Ira L. 1964. Vegetation and flora of the
       Sonoran Desert. Stanford, CA: Stanford University Press. 1575 p.  [4595]

.  Stubbendieck, J.; Hatch, Stephan L.; Hirsch, Kathie J. 1986. North
       American range plants. 3rd ed. Lincoln, NE: University of Nebraska
       Press. 465 p.  [2270]

.  Szarek, S. R.; Woodhouse, R. M. 1976. Ecophysiological studies of
       Sonoran Desert Plants. II. Diurnal photosynthesis patterns of Ambrosia
       deltoidea and Olneya tesota. Oecologia. 26: 225-234.  [4319]

.  Thornburg, Ashley A. 1982. Plant materials for use on surface-mined
       lands. SCS-TP-157. Washington, DC: U.S. Department of Agriculture, Soil
       Conservation Service. 88 p.  [3769]

.  Tueller, Paul T. 1976. Secondary succession, disclimax, and range
       condition standards in desert scrub vegetation. In: Hyder, D. N., ed.
       Arid shrublands--Proceedings of the third workshop of the United
       States/Australia rangelands panel; 1973 March 26 - April 5; Tucson, AZ.
       Denver, CO: Society for Range Management: 57-65.  [3790]

.  Turner, Raymond M.; Brown, David E. 1982. Sonoran desertscrub. In:
       Brown, David E., ed. Biotic communities of the American
       Southwest--United States and Mexico. Desert Plants. 4(1-4): 181-221. 
       [2375]

.  Whitfield, Charles J.; Anderson, Hugh L. 1938. Secondary succession in
       the desert plains grassland. Ecology. 19(2): 171-180.  [5252]

.  Whysong, Gary L.; Heisler, Michael H. 1978. Nitrogen levels of soil and
       vegetation in the upper Sonoran Desert as affected by fire. In: Hyder,
       Donald N., ed. Proceedings, 1st international rangeland congress; 1978
       August 14-18; Denver, CO. Denver, CO: Society for Range Management:
       697-699.  [3990]

.  Yeaton, Richard I.; Travis, J.; Gilinsky, Ellen. 1977. Competition and
       spacing in plant communities: the Arizona upland association. Journal of
       Ecology. 65: 587-595.  [4193]

.  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. 
       [434]

.  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.  [998]

.  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.  [1384]

.  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. 7 p.  [20090]

.  Raunkiaer, C. 1934. The life forms of plants and statistical plant
       geography. Oxford: Clarendon Press. 632 p.  [2843]

.  U.S. Department of Agriculture, Soil Conservation Service. 1994. Plants
       of the U.S.--alphabetical listing. Washington, DC: U.S. Department of
       Agriculture, Soil Conservation Service. 954 p.  [23104]

.  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.  [23119]

.  McAuliffe, Joseph R. 1986. Herbivore-limited establishment of a Sonoran
       Desert tree, Cercidium microphyllum. Ecology. 67(1): 276-280.  [2756]

Related categories for Species: Ambrosia deltoidea | Triangle Bursage