Introductory
SPECIES: Ambrosia psilostachya | Western Ragweed 



ABBREVIATION : 
AMBPSI

SYNONYMS : 
   Ambrosia rugelii Rydb.
   Ambrosia coronopifolia T. & G.


SCS PLANT CODE : 
   AMPS


COMMON NAMES : 
   western ragweed
   perennial ragweed
   common ragweed
   ragweed


TAXONOMY : 
The currently accepted name of western ragweed is Ambrosia psilostachya
DC.; it is a member of the sunflower family (Asteraceae).  There are
three recognized varieties [51]:

        A. p. var. psilostachya
        A. p. var. californica (Rydb.) Blake
        A. p. var. lindeheimerana (Scheele) Blank.


LIFE FORM : 
Forb

FEDERAL LEGAL STATUS : 
No special status

OTHER STATUS : 
NO-ENTRY


COMPILED BY AND DATE : 
Diane S. Pavek, November 1992


LAST REVISED BY AND DATE : 
NO-ENTRY


AUTHORSHIP AND CITATION : 
Pavek, Diane S. 1992. Ambrosia psilostachya. In: Remainder of Citation

DISTRIBUTION AND OCCURRENCE
SPECIES: Ambrosia psilostachya | Western Ragweed 



GENERAL DISTRIBUTION : 
Western ragweed's range extends from southern British Columbia east to
Nova Scotia [51,81,107] and southward through the United States from the
Appalachians to the West Coast and into central Mexico
[38,74,90,104,108].  Western ragweed was introduced from North America
into Europe and southwestern Russia [115].


ECOSYSTEMS : 
   FRES15  Oak - hickory
   FRES21  Ponderosa pine
   FRES31  Shinnery
   FRES32  Texas savanna
   FRES33  Southwestern shrubsteppe
   FRES34  Chaparral - mountain shrub
   FRES38  Plains grasslands
   FRES39  Prairie
   FRES42  Annual grasslands


STATES : 
     AZ  CA  CO  CT  ID  IL  IA  KS  LA  ME
     MA  MI  MO  MN  MT  NE  NH  NC  ND  OH
     OK  OR  SC  SD  TX  UT  VT  WA  WI  WY
     AB  BC  MB  NS  ON  PE  PQ  SK  MEXICO


ADMINISTRATIVE UNITS : 
     AGFO  AMIS  BITH  CACA  CHIR  COLM
     CODA  GLAC  GRCA  GUMO  JELA  LAME
     LAMR  MOCA  PAIS  PIPE  ROMO  SAMO
     SCBL  SLBE  THRO  WACA  WICA  WUPA
     ZION


BLM PHYSIOGRAPHIC REGIONS : 
    3  Southern Pacific Border
    5  Columbia Plateau
    7  Lower Basin and Range
   10  Wyoming Basin
   12  Colorado Plateau
   13  Rocky Mountain Piedmont
   14  Great Plains
   16  Upper Missouri Basin and Broken Lands


KUCHLER PLANT ASSOCIATIONS : 
   K033  Chaparral
   K035  Coastal sagebrush
   K053  Grama - galleta steppe
   K054  Grama - tobosa prairie
   K057  Galleta - three-awn shrubsteppe
   K058  Grama - tobosa shrubsteppe
   K060  Mesquite savanna
   K061  Mesquite - acacia savanna
   K062  Mesquite - live oak savanna
   K063  Foothills prairie
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss
   K067  Wheatgrass - bluestem - needlegrass
   K068  Wheatgrass - grama - buffalograss
   K069  Bluestem - grama prairie
   K070  Sandsage - bluestem prairie
   K071  Shinnery
   K074  Bluestem prairie
   K075  Nebraska Sandhills prairie
   K076  Blackland prairie
   K078  Southern cordgrass prairie
   K081  Oak savanna
   K084  Cross Timbers
   K085  Mesquite - buffalograss
   K086  Juniper - oak savanna
   K087  Mesquite - oak savanna
   K100  Oak - hickory forest


SAF COVER TYPES : 
    40  Post oak - blackjack oak
    42  Bur oak
    66  Ashe juniper - redberry (Pinchot) juniper
    68  Mesquite
    72  Southern scrub oak
    73  Southern redcedar
    89  Live oak
   220  Rocky Mountain juniper
   235  Cottonwood - willow
   238  Western juniper
   242  Mesquite
   244  Pacific ponderosa pine - Douglas-fir
   255  California coast live oak


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Western ragweed is a principal or dominant forb in many grasslands, such
as little bluestem (Schizachyrium scoparium) and shortgrass communities
[6].  It is of secondary importance in big bluestem (Andropogon gerardii
var. garardii) communities, but it is still the dominant forb [6,113].
It is a dominant forb in the Cross Timbers range, sand plains, and
prairies of Texas [44,86].  Western ragweed is dominant in sand
tallgrass prairies and sand hills of the Midwest [105,120].  It is the
principal forb in the shortgrass-ponderosa pine (Pinus ponderosa)
woodlands of north-central Arizona [18,28,60].  Western ragweed is
present in the Gambel oak (Quercus gambeli) grasslands of the west
[29,39].  Western ragweed is codominant in saltgrass (Distichlis
spicata) communities and in grasslands found above salt marshes [22,26,
34,42].

In riparian habitat types of Wyoming, western ragweed is listed as
codominant with western wheatgrass (Pascopyrum smithii) in the
Grass/Sedge Meadow subtype [90].  Western ragweed is a important forb,
but not an indicator, in steppe habitat types of North Dakota and South
Dakota:  (1) needle-and-thread grass (Stipa comata)/threadleaf sedge
(Carex filifolia), (2) green ash (Fraxinum pennsylvanica)/common
chokecherry (Prunus virginiana), and in Montana:  (1) needle-and-thread
grass/sun sedge (Carex heliophila), (2) Idaho fescue (Festuca
idahoensis)/sun sedge, (3) bluebunch wheatgrass (Psuedoroegnaria
spicata)/sideoats grama (Bouteloua curtipendula), (4) bluebunch
wheatgrass/threadleaf sedge, (5) fragrant sumac (Rhus aromatica)/
bluebunch wheatgrass, and (6) fragrant sumac/Idaho fescue [64].

Publications that list western ragweed as dominant are:

(1)  The vegetation of the Grand River/Cedar River, Sioux, and Ashland
     Districts of the Custer National Forest: a habitat type
     classification [64]. 
(2)  A physical and biological characterization of riparian habitat and its
     importance to wildlife in Wyoming [90].

VALUE AND USE
SPECIES: Ambrosia psilostachya | Western Ragweed 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Managers rate the forage value of western ragweed as fair [121].  The
foliage and stems contain cinnamic acid and sesquiterpene lactones that
deter herbivory [129].  However, western ragweed is not considered a
poisonous plant [88].  It is moderately important as ungulate forage
[24,31,48,98,103].  Western ragweed is used for food and nesting
material, and as a habitat component by small mammals and nongame birds
[10,52,63].  Western ragweed is an important food (seeds and foliage) on
activity sites for upland gamebirds [11,73,110,123].  In a study of the
relationship of grasshoppers to different pasture treatments and range
sites in Kansas tallgrass paririe, western ragweed was one of the two
most abundantly available and most ingested forbs [78].


PALATABILITY : 
Ragweeds are normally considered to be unpalatable but when treated with
2,4-D become palatable.  Treated plants may, however, accumulate
nitrates to a toxic level [76].  In Montana, Utah, and Wyoming, western
ragweed palatability is poor for ungulates and waterfowl.  Its
palatibility has mixed ratings for the following species:

                           MT      UT      WY
    Small mammals                 Poor    Good
    Small nongame birds   Good    Poor    Good
    Upland game birds     Fair    Poor    Fair


NUTRITIONAL VALUE : 
Mature western ragweed seeds from an eastern Texas prairie contained 1
to 3 percent silica, which reduces digestibility; the seeds had 70 to
less than 90 percent dry matter digestibility [109].  However, the seeds
contained more than 25 percent protein.  Forage quality (seasonal crude
protein content and digestibility) of western ragweed on a Texas range
was higher after spring burning [17].


COVER VALUE : 
The degree to which western ragweed provides environmental protection
during one or more seasons for wildlife species is as follows:

                                MT      UT      WY
        Pronghorn              ----    Poor    Poor
        Elk                    ----    Poor    Poor
        Mule deer              ----    Poor    Poor
        White-tailed deer      ----    ----    Poor
        Small mammals          Poor    Fair    Poor
        Small nongame birds    Poor    Fair    Poor
        Upland game birds      ----    Poor    Poor
        Waterfowl              ----    Poor    Poor


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Although western ragweed readily invades disturbed ground and is not
considered desirable forage, it is a native forb and is included in
prairie restoration plantings.  Adequate seedbed preparation is
important for successful plant establishment [37,117].  Western ragseed
was seeded for tallgrass prairie restoration in north-central Missouri
at 0.08 pounds bulk per acre (91 g bulk/ha) with a rangeland drill
[117].  In the reclamation of a sand and gravel pit in Ohio, western
ragweed was hydroseeded with native grasses; seeds were covered with
less than 0.5 inch (1 cm) of soil [37].  Western ragweed has established
on artificial levees made to reclaim marshland along the lower
Sacramento River in California [127].

Established western ragweed may have to be controlled when planting
other native species in an area.  For example, when fourwing saltbush
(Atriplex canescens) was planted on shrublands in Texas, western ragweed
was controlled with herbicides [95].


OTHER USES AND VALUES : 
Western ragweed was used for medicinal purposes by American Indians.
Pueblo women in New Mexico drank a tea made from western ragweed during
difficult labors at childbirth, and the Cheyenne of the Central Plains
used it to treat intestinal problems and colds [12].  Kiowa of Oklahoma
rubbed a preparation of western ragweed on the sores of humans and
horses [12].


MANAGEMENT CONSIDERATIONS : 
Western ragweed is one of the main hay-fever plants in late summer when
it is in bloom [70,74,130].

Western ragweed is a major invader of deteriorating rangeland.  It
readily moves into open habitat in prairies [19,121].  Western ragweed
is not drought resistant.  It was partially or totally eliminated from
mixed-grass prairies during the drought of the 1930s; however, western
ragweed recovered by the mid-1940s [40,121].

Livestock:  Western ragweed averaged 1,200 pounds of dry matter per acre
(1,342 kg/ha) on a clay upland range site near Hays, Kansas, and was
beneficial to grass production [83].  Grass yields were never less than
2,000 pounds per acre (2,237 kg/ha) from sites that produced 7,000
pounds per acre (7,830 kg/ha) western ragweed [83].  A buildup of 3 to 5
inches (8-13 cm) of grass mulch on a lightly grazed rangeland delayed
western ragweed growth in the spring; however, litter increased the
moisture supply [71,122].

For optimum use of western ragweed on shortgrass rangeland, continuous
season-long or year-long grazing at moderate stocking rates, combined
with spring burning, is recommended [83].  Launchbaugh and Owensby [83]
recommend grazing western ragweed early in the growing season.  Range
cattle consume western ragweed by choice most heavily in April [48].

Western ragweed cover increases when it is grazed or disced
[44,57,94,123].  There was no significant (P>0.05) difference in
relative abundance of western ragweed under moderate or heavy stocking
rates [67,69].  However, western ragweed cover was significantly greater
on continuously grazed pasture compared with short duration grazing
[31,45].  Western ragweed herbage was significantly higher under thinned
ponderosa pine compared to unthinned areas [28].  Herbage production of
western ragweed decreased as the depth of humus, duff, and litter
increased under ponderosa pine canopies [29].

Chemical Control:  Herbicide should be applied to western ragweed during
the late vegetative stage before the formation of flowerbuds; western
ragweed is moderately or totally resistant during other growth phases
[93,111].  Before flowering, it is susceptible and may be controlled
with one foliage spray application at 1 pound active ingredient per acre
(1.1 kg ai/ha) for 2,4-D, 2,4,5-T, Silvex, 2,4,-D-B or 0.25 pound active
ingredient per acre (0.28 kg ai/a) Grazon PC and Banvel [43,83,93].
Grazon P + D will give control for more than 1 year [43].

Western ragweed root exudate significantly inhibited the formation of
nodules on legume roots, which decreases their ability to fix nitrogen
[128].

Western ragweed repsonds differently to different combinations of
disturbance and burning.  Western ragweed occurred significantly more on
unburned pocket gopher mounds than on burned; it occurred less
frequently on ant hills than on controls [55].  Western ragweed had
significantly higher average cover on burned areas immediately outside
of buffalo wallows compared to unburned controls [36].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ambrosia psilostachya | Western Ragweed 



GENERAL BOTANICAL CHARACTERISTICS : 
Western ragweed is a warm-season, native perennial forb.  The main stem
rises from shallow (2 inches [5 cm]) or deep, branching rhizomes which
extend down 3 to 6 feet (0.9-1.8 m) [6,70].  Stems are slender and
branched, usually 1 to 2 feet (30-60 cm) tall [59,70].  Plants are
monoecious with unisexual flowers; male flowers occur at the top of the
plant and female flowers are axillary [41].  Achenes have a short beak
and small blunt tubercles on top [41].


RAUNKIAER LIFE FORM : 
   Geophyte


REGENERATION PROCESSES : 
Western ragweed colonizes sites by means of spreading rhizomes in the
surface 2 inches (5 cm) of soil, allowing it to propagate when
conditions are unfavorable to seedling establishment [6,48,127].
Western ragweed exhibits nonrandom replacement of ramets, which allows
it to exploit areas favorable to growth [87].

Seeds are reported to migrate into disturbed areas; however, the means
of dissemination was not identified [6].  In a germination trial using 1
square foot (0.09 sq. m) soil samples, western ragweed seedlings did not
appear until week 6 or 7 [84].  After this time, seeds continued to
germinate for 3 weeks [84].

Once seeded into an area, western ragweed may not set fruit until the
second year [37].  Under dry conditions, seed production is somewhat
inversely proportional to plant density.  A dense stand of western
ragweed in a dry summer resulted in stunted growth, and most plants died
without fruiting [72].


SITE CHARACTERISTICS : 
Western ragweed grows in grasslands, savannas, and woodlands across
North America.  In addition to occurring in its native settings (such as
dry prairies, blowouts, washouts, sandy woods, meadows, and hills),
western ragweed is a widespread weed in waste places, roadsides,
railroads, overgrazed rangeland, and other disturbed places
[41,75,99,107,126].

Climate ranges from continental to coastal with short, warm to hot
summers and long, cold winters [1,3,16,129].  Often, there are
moderately strong surface winds [1].  Humidity is semiarid to moist
subhumid [42,44,86].  Annual precipitation ranges from 5 to 34 inches
(114-880 mm) with 60 to 80 percent occurring during the growing season
[19,23,39,56,75,114,125].  Temperatures vary from an average 72 degrees
Fahrenheit (22 deg C) in July to a January average of 11 degrees
Fahrenheit (-11.5 deg C) [124].

Western ragweed grows at elevations ranging from 850 to 7,400 feet
(259-2,256 m) and in many types of soils [18,30,60,66,69].  Soil
textures are predominantly loams, varying from silty clay loams to fine
sandy loams [23,61,122].  Soil pH ranges from 5.7 to 7.9 [22,105].
Soils often have little organic matter and are low in fertility [34].

Western ragweed occurs in too many grassland ecosystems for associated
species to be reviewed here.  Listed below are some typical examples of
major grasslands and the plant components found with western ragweed.
In addition to this brief listing, the reader is referred to specific
examples of more distinct and diverse grasslands in which western
ragweed occurs [11,15,18,19,20,22,25,26,28,29,32,33,39,42,49,129].

Southern Great Plains 
Shortgrass prairie is dominated by buffalograss (Buchloe dactyloides)
and blue grama (Bouteloua gracilis) with sand dropseed (Sporobolus
cryptandrus [132].  When trees occur, sand shinnery oak (Quercus
havardii) is dominant [45,118].

Mixed-grass prairie is dominated by sideoats grama (Bouteloua
curtipendula), buffalograss, little bluestem, and tobosagrass (Hilaria
mutica) [132].  When an overstory is present, dominant trees are honey
mesquite (Prosopis glandulifera), Ashe juniper (Juniperus ashei), post
oak (Quercus stellata), blackjack oak (Q. marilandica), and live oak (Q.
virginiana) [59,67,86,112].  Shrubs include cholla (Opuntia imbricata),
common broomweed (Xanthocephalum dracunculoides), and whitebrush
(Aloysia lycoiodes) [47,66,123].  An associated forb is Riddel daisy
(Aphanostephus riddellii) [47,65].

Tallgrass prairie is dominated by little bluestem, silver bluestem
(Andropogon saccharoides), and fewflowered panic (Dicanthelium
oligosanthes) [36].

Central Great Plains Shortgrass dominated by blue grama with
buffalograss, sand reedgrass (Calamovilfa longifolia), and prairie
dropseed (Sporobolus heterolepis) [82,122,132].  An associated forb is
horseweed (Conyza canadensis) [43].

Northern Great Plains Tallgrass prairie is dominated by big bluestem
with little bluestem, Indiangrass (Sorghastrum nutans), and switchgrass
(Panicum virgatum) [132].  A shrub co-occurring with western ragweed is
Louisiana sandwort (Artemisia ludoviciana) [120].  Codominant forbs are
heath aster (Aster ericoides), purple prairie-clover (Petalostemum
purpureum), and goldenrods (Solidago spp.)  [1,35,106,120].

Western ragweed occurs on floodplain woodlands with sand reedgrass and
Canadian wildrye (Elymus canadensis) [4,117].  The overstory is
dominated by floodplain cottonwood (Populus deltoides) with green ash
(Fraxinus pennsylvanica) [117].


SUCCESSIONAL STATUS : 
Facultative Seral Species

Differing sets of seral stages have been suggested for secondary
succession in prairie ecosystems, and western ragweed has been reported
to occur in all of them and in climax communities [97,102].  Western
ragweed establishes in closed communities that are opened up by heavy
grazing or other disturbance [103].  In old field succession, western
ragweed was present as a principal forb in stands aged 0 to 5 years and
was present with 4 to 15 percent cover after 23 to 29 years [33,48].  On
abandoned black-tailed prairie dog towns, western ragweed was codominant
with an annual grass, prairie threeawn (Aristida oligantha), in an
intermediate seral stage [10,91].  In tallgrass sand prairie, western
ragweed was present in pioneer stages, occurred with greatest frequency
in an intermediate phase, but had greatest cover in the climax phase
[25].  Although reported as a pioneer species, western ragweed occurs on
secondary sand dunes but does not occur on less stable sites such as
primary dunes or tidal flats [27].  Additionally, western ragweed occurs
outside of buffalo wallows, which are considered safe sites for ruderal
species [36].

Western ragweed may have alleopathic or other inhibitory effects on
other pioneer species.  Leachate from western ragweed leaves and roots
significantly (P<0.05) reduced growth of soil bluegreen bacteria (Lyngby
spp.)  cultures [102].  While soil collected in July near western
ragweed was stimulatory to pioneer weedy species (for example, Japanese
brome [Bromus japonicus]), soil collected in January had an inhibitory
or no effect on seedlings of the same species [102].  Leaf leachate from
leaves that overwintered on western ragweed plants inhibited
germination, seedling topgrowth, and mature plant root formation of the
pioneer species [102].


SEASONAL DEVELOPMENT : 
Western ragweed is widespread, so specific dates for phenological stages
vary; however, stages of growth occur seasonally.  The months in
parentheses represent the center of its distribution.  Western ragweed,
a warm season plant, overwinters as a rosette [103].  In mid-spring
(April), seedlings germinate, and rosettes begin active growth of main
stems.  In late summer (August), western ragweed flowers, and seedlings
may germinate with adequate rainfall [5].  It is at this time of year
that western ragweed usually has its greatest biomass [96].  Flowering
continues through autumn [17,41,51,81,89,99].  Fruits form and seeds
disseminate through the late fall and winter (October to December) [5].
Aerial stems are killed by frost.

FIRE ECOLOGY
SPECIES: Ambrosia psilostachya | Western Ragweed 



FIRE ECOLOGY OR ADAPTATIONS : 
As a component of North American grasslands, western ragweed has evolved
with fire.  Soil can insulate roots from lethal temperatures during a
fire.  Surface rhizomes of western ragweed may be killed during a fire;
however, the plant also has deep-seated rhizomes which would survive
most fires [6].


POSTFIRE REGENERATION STRATEGY : 
   Geophyte, growing points deep in soil
   Rhizomatous herb, rhizome in soil
   Secondary colonizer - off-site seed

FIRE EFFECTS
SPECIES: Ambrosia psilostachya | Western Ragweed 



IMMEDIATE FIRE EFFECT ON PLANT : 
Western ragweed is top-killed by fire.  Shallow rhizomes may be killed
along with seeds on aerial stems.


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Season of burning, community type, and subsequent environmental
conditions determine western ragweed response to burning.  In some
studies, no significant (P>0.05) difference was found in western ragweed
postfire herbage, cover, or occurrence, despite the season burned
[4,72,79,82,92,131].

Western ragweed cover was significantly decreased by annual spring
burning in tallgrass prairies and honey mesquite communities [2,66].
However, other studies showed that western ragweed significantly
increased in cover or was more abundant on spring burned grasslands and
oak savanna [7,13,68,124].  Late spring burning decreased western
ragweed cover, and winter burning increased it [4,15,20].  The density
of western ragweed was increased by annual fall (October) burning
[16,21,106].

One year postfire, western ragweed cover was significantly less on
burned areas compared to unburned areas [19].  Prescribed burning in
juniper (Juniperus spp.) communities of Texas in late winter or early
spring increased western ragweed density 1 year postfire [100].  The
second and following years showed no further effects on western ragweed
densities [100].

After a spring (May) fire in a Kansas tallgrass prairie, western ragweed
increased significantly by year 3 in number of stems per 3.3 square feet
(1 sq m) [46].  Other tallgrass prescribed spring fires were conducted
annually and on a 4-year rotation.  Western ragweed cover was
significantly greater on the 4-year rotation compared to the annual
burning [3].  Four-year fire rotation was used to compare vegetative
response on shallow upland soils with lowland soils in tallgrass prairie
in Kansas.  Western ragweed was significantly more abundant on the
shallow upland soils after burning [54].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Western ragweed has been classified as an increaser (by 100 percent or
more) on burned plots [77].

References for species: Ambrosia psilostachya

1. Abrams, Marc D. 1988. Effects of burning regime on buried seed banks and canopy coverage in a Kansas tallgrass prairie. The Southwestern Naturalist. 33(1): 65-70. [4415]

2. Abrams, Marc D.; Gibson, David J. 1991. Effects of fire exclusion on tallgrass prairie and gallery forest communities in eastern Kansas. In: Nodvin, Stephen C.; Waldrop, Thomas A., eds. Fire and the environment: ecological and cultural perspectives: Proceedings of an international symposium; 1990 March 20-24; Knoxville, TN. Gen. Tech. Rep. SE-69. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station: 3-10. [16627]

3. Abrams, Marc D.; Hulbert, Lloyd C. 1987. Effect of topographic position and fire on species composition in tallgrass prairie in northeast Kansas. The American Midland Naturalist. 117(2): 442-445. [291]

4. Adams, Dwight E.; Anderson, Roger C.; Collins, Scott L. 1982. Differential response of woody and herbaceous species to summer and winter burning in an Oklahoma grassland. The Southwestern Naturalist. 27: 55-61. [6282]

5. Ahshapanek, D. C. 1962. Phenology of a tall-grass prairie in central Oklahoma. Ecology. 43: 135-138. [5598]

6. Albertson, F. W. 1937. Ecology of mixed prairie in west central Kansas. Ecological Monographs. 7: 483-547. [5057]

7. Anderson, Kling L.; Smith, Ed F.; Owensby, Clenton E. 1970. Burning bluestem range. Journal of Range Management. 23: 81-92. [323]

8. Anderson, Roger C.; Leahy, Theresa; Dhillion, Shivcharn S. 1989. Numbers and biomass of selected insect groups on burned and unburned sand prairie. The American Midland Naturalist. 122: 151-162. [7912]

9. Anderson, Roger C.; Liberta, Anthony E. 1987. Variation in vesicular-arbuscular mycorrhizal relationships of two sand prairie species. The American Midland Naturalist. 118(1): 56-63. [2920]

10. Archer, Steven R. 1983. Plant community structure, competitive interactions and water relations as influenced by herbivores. Fort Collins, CO: Colorado State University. 114 p. Dissertation. [338]

11. Ault, Stacey C.; Stormer, Fred A. 1983. Seasonal food selection by scaled quail in northwest Texas. Journal of Wildlife Management. 47(1): 222-228. [12168]

12. Bare, Janet E. 1979. Wildflowers and weeds of Kansas. Lawrence, KS: The Regents Press of Kansas. 509 p. [3801]

13. Becker, Donald A. 1989. Five years of annual prairie burns. In: Bragg, Thomas A.; Stubbendieck, James, eds. Prairie pioneers: ecology, history and culture: Proceedings, 11th North American prairie conference; 1988 August 7-11; Lincoln, NE. Lincoln, NE: University of Nebraska: 163-168. [14037]

14. 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]

15. Bidwell, Terrence G.; Engle, David M.; Claypool, P. Larry. 1990. Effects of spring headfires and backfires on tallgrass prairie. Journal of Range Management. 43(3): 209-212. [11141]

16. Biondini, M. E.; Steuter, A. A.; Grygiel, C. E. 1989. Seasonal fire effects on the diversity patterns, spatial distribution and community structure of forbs in the Northern Mixed Prairie, USA. Vegetatio. 85: 21-31. [10180]

17. Bogle, Laurie A.; Engle, David M.; McCollum, F. Ted. 1989. Nutritive value of range plants in the Cross Timbers. Report P-908. Stillwater, OK: Oklahoma Agricultural Experiment Station. 29 p. [9293]

18. Bojorquez Tapia, Luis A.; Ffolliott, Peter F.; Guertin, D. Phillip. 1990. Herbage production-forest overstory relationships in two Arizona ponderosa pine forests. Journal of Range Management. 43(1): 25-28. [11509]

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