Introductory
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



ABBREVIATION : 
TETGLA

SYNONYMS : 
NO-ENTRY


SCS PLANT CODE : 
   TEGL


COMMON NAMES : 
   littleleaf horsebrush
   coal oil brush
   smooth horsebrush


TAXONOMY : 
Strother's 1974 revision of the genus Tetradymia recognizes littleleaf
horsebrush as Tetradymia glabrata Torr. & Gray and puts T. glabrata f.
calva Payson in synonymy with it [13].



LIFE FORM : 
Shrub

FEDERAL LEGAL STATUS : 
No special status

OTHER STATUS : 
NO-ENTRY


COMPILED BY AND DATE : 
Kathy Ahlenslager, May 1986


LAST REVISED BY AND DATE : 
Kathy Ahlenslager  December 1987



AUTHORSHIP AND CITATION : 
Ahlenslager, Kathleen E. 1986. Tetradymia glabrata. In: Remainder of Citation

DISTRIBUTION AND OCCURRENCE
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



GENERAL DISTRIBUTION : 
Littleleaf horsebrush occurs throughout the Great Basin, from eastern
Oregon and western Idaho south through northeastern California and
Nevada to Owens Valley, Antelope Valley, and edges of the Mojave Desert
and east to Wayne County, Utah [3,10,13].


ECOSYSTEMS : 
   FRES21  Ponderosa pine
   FRES26  Lodgepole pine
   FRES29  Sagebrush
   FRES30  Desert shrub
   FRES35  Pinyon - juniper
   FRES36  Mountain grasslands
   FRES38  Plains grasslands
   FRES40  Desert grasslands


STATES : 
     CA  NV  OR  UT


ADMINISTRATIVE UNITS : 
     CARE  DEVA


BLM PHYSIOGRAPHIC REGIONS : 
   5  Columbia Plateau
   6  Upper Basin and Range
   7  Lower Basin and Range
   8  Northern Rocky Mountains


KUCHLER PLANT ASSOCIATIONS : 
   K022  Great Basin pine forest
   K023  Juniper - pinyon woodland
   K024  Juniper steppe woodland
   K038  Great Basin sagebrush
   K040  Saltbush - greasewood
   K041  Creosotebush
   K050  Fescue - wheatgrass
   K051  Wheatgrass - bluegrass
   K053  Grama - galleta steppe
   K055  Sagebrush steppe
   K063  Foothills prairie
   K066  Wheatgrass - needlegrass


SAF COVER TYPES : 
   220  Rocky Mountain juniper
   238  Western juniper
   239  Pinyon - juniper


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Since littleleaf horsebrush is a seral species, it is used an indicator
species in any habitat types.  This species is characteristic of the
lower portion of the sagebrush zone and upper salt desert [Young pers.
comm. 1987].  Throughout its range it is associated with sagebrush
(Artemisia spp.), cresotebush (Larrea tridentata), Joshua tree (Yucca
brevifolia) woodlands, and pinyon-juniper vegetation types [10].

VALUE AND USE
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Even though littleleaf horsebrush is not ordinarily palatable to
livestock, buds and young leaves are eaten by sheep, goats, pronghorn,
and deer on desert, overgrazed, and depleted rangelands, as well as ib
winter and early spring ranges.  This species is poisonous and has
caused the death of thousands of animals in Utah and Nevada.  Abortion
may also occur as a result of rapid liver damage [7,8].

Littleleaf horsebrush is twice as toxic as gray horsebrush (Tetradymia
canescens), and animals are less likely to recover from its poisioning
[10].  The toxicity of plants in the same stage of development varies
with locality.  Plants are most toxic in the spring, and poisoning may
occur if large quantities are consumed [10,12,13].  Toxicity is mostly
lost after flowering.  Littleleaf horsebrush is most dangerous in April
and May when it is growing rapidly.

Consumption of big sagebrush (Artemisia tridentata) or black sagebrush
(A. nova) and littleleaf horsebrush predisposes sheep to
photosensitization.  This can develop rapidly with several hundred sheep
becoming affected within 2 to 3 hours.  Littleleaf horsebrush is more
toxic than gray horsebrush, but gray horsebrush is more likely to cause
photosensitization, probably because of its lesser toxicity [8].  The
ingestion of 0.5 percent body weight of young leaves and twigs can
result in liver damage and associated photosensitization, which in turn
leads to capillary breakage, edema, and head swelling (bighead).  Sheep
usually do not recover from bighead.  Cattle are not affected by this
problem [10,12,13].


PALATABILITY : 
The palatability of littleleaf horsebrush in Utah is rated fair for
sheep but poor for cattle and horses [4].  This toxic species is
especially dangerous during bud stage when it is most palatable [6].


NUTRITIONAL VALUE : 
Littleleaf horsebrush is rated poor in energy and protein value [4].


COVER VALUE : 
In dry, sparsely vegetated desert ranges, littleleaf horsebrush provides
needed ground cover [12].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
The potential for erosion control for littleleaf horsebrush in Utah is
low, as is its potential for revegetation.  Its establishment
requirements are also low [4].


OTHER USES AND VALUES : 
NO-ENTRY


MANAGEMENT CONSIDERATIONS : 
Sheep should be managed so as to avoid littleleaf horsebrush [6].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



GENERAL BOTANICAL CHARACTERISTICS : 
Littleleaf horsebrush is a native, perennial, heavily branched shrub up
to 4 feet (12 dm) in height [10,13].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Littleleaf horsebrush regenerates vegetatively through root bud
sprouting, as well as sexually via wind-dispersed seeds.  After fires
regeneration is by basal stem sprouts [14].


SITE CHARACTERISTICS : 
Plants of littleleaf horsebrush occur in dry, open foothills and plains
from 2,600 to 8,000 feet (800-2,400 m) [3,10,13].  In Utah it is occurs
at elevations from 4,500 to 5,700 feet (1,370-1,740 m) and is limited to
higher valley benchlands.  Littleleaf horsebrush is found most
extensively on well-drained gentle slopes with coarse-textured soil,
varying from gravel to large boulders.  It also occurs in sandy areas
[5].


SUCCESSIONAL STATUS : 
Littleleaf horsebrush persists in high seral communities and has the
ability to increase in abundance during secondary succession through
vigorously sprouting roots.  Although flowers are highly fertile,
seedlings are rarely observed in nature.  This is probably due to the
harsh environment in which the species occurs [13].


SEASONAL DEVELOPMENT : 
Dormant throughout the winter, littleleaf horsebrush is one of the
earliest desert range shrubs to begin growing in the spring.  Plants are
green by late March and drop leaves in early July [6].

Littleleaf horsebrush begins flowering during late April in the southern
part of its range in the Mohave Desert and during mid-June in Idaho
[13].  As is typical of many xerophytes, the flowering of littleleaf
horsebrush is correlated with distribution and rainfall.  In very dry
years some individuals or entire colonies do not bloom at all, or bloom
but fail to mature fruits.  This is probably due to decreases in water
availability [13].  One way xerophytic species cope with a short growing
season is to flower simultaneously.  Often plants of whole colonies
bloom at once or bloom within a few days of each other [13].

FIRE ECOLOGY
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



FIRE ECOLOGY OR ADAPTATIONS : 
Plants of littleleaf horsebrush stand dormant throughout most of the
year on the dry ranges where they occur.  During a fire these
much-branched shrubs burn rapidly, with little heat transferred downward
into the roots.  Fire stimulates the roots of littleleaf horsebrush to
sprout [14].


POSTFIRE REGENERATION STRATEGY : 
   Small shrub, adventitious-bud root crown
   Ground residual colonizer (on-site, initial community)

FIRE EFFECTS
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



IMMEDIATE FIRE EFFECT ON PLANT : 
The effect of fire on shrubs is more damaging than that on forbs and
grasses.  Fire not only destroys herbage, but also the stored reserves
of shrubs.  Littleleaf horsebrush is considered a fire-resistant
species, becaise there is a 65 percent or greater chance that at least
50 percent of a population will survive or reestablish after a fire
[14,15].  Although littleleaf horsebrush resprouts after a fire, it
generally grows on dry sites where there is usually not enough fuel to
carry a fire [16,17].



DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Littleleaf horsebrush, which is capable of resprouting and rapid
regrowth after fire, is favored over other plants that reestablish only
by seed [2].  Postfire regeneration response is considered rapid:  2 to
5 years to approximate preburn frequency or cover [14].  Plants quickly
regain and surpass their original size.  The amount of sprouting is
affected by season and soil moisture, as these are factors which
contribute to burning intensity.

After a fire sprouting littleleaf horsebrush may initially dominate
sagebrush ranges.  In addition to the vigorous postburn production of
root sprouts, there is dynamic seedling establishment [17].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
NO-ENTRY

REFERENCES
SPECIES: Tetradymia glabrata | Littleleaf Horsebrush 



REFERENCES : 

 .  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]

 .  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]

 .  Cronquist, Arthur. 1955. Vascular plants of the Pacific Northwest: Part
       5: Compositae. Seattle: University of Washington Press. 343 p.  [716]

 .  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.  [806]

 .  Fautin, Reed W. 1946. Biotic communities of the northern desert shrub
       biome in western Utah. Ecological Monographs. 16: 252-310.  [913]

 .  James, L. F.; Keeler, R. F.; Johnson, A. E.; [and others]. 1980. Plants
       poisonous to livestock in the western states. Agriculture Information
       Bulletin 415. Washington, DC: U.S. Department of Agriculture, Science
       and Education Administration. 90 p.  [1243]

 .  Johnson, A. Earl. 1974. Predisposing influence of range plants on
       Tetradymia-related photosensitization in sheep: work of Drs. A.B.
       Clawson & W.T. Huffman. American Journal of Veterinary Research. 35(12):
       1583-1585.  [1269]

 .  Johnson, A. Earl. 1987. The relationship of Tetradymia species and
       Artemisia nova to photosensitization in sheep. In: Provenza, Frederick
       D.; Flinders, Jerran T.; McArthur, E. Durant, compilers.
       Proceedings--symposium on plant- herbivore interactions; 1985 August
       7-9; Snowbird, UT. Gen. Tech. Rep. INT-222. Ogden, UT: U.S. Department
       of Agriculture, Forest Service, Intermountain Research Station: 113-117.
       [1270]

 .  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]

.  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.  [1571]

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

.  Stoddart, L. A.; Holmgren, A. H.; Cook, C. W. 1949. Important poisonous
       plants of Utah. Special Report No. 2. Logan, UT: Utah State Agricultural
       College, Agricultural Experiment Station. 21 p.  [2259]

.  Strother, John L. 1974. Taxonomy of Tetradymia (Compositae:
       Senecioneae). Brittonia. 26: 177-202.  [2268]

.  Volland, Leonard A.; Dell, John D. 1981. Fire effects on Pacific
       Northwest forest and range vegetation. Portland, OR: U.S. Department of
       Agriculture, Forest Service, Pacific Northwest Region, Range Management
       and Aviation and Fire Management. 23 p.  [2434]

.  Wright, Henry A. 1972. Shrub response to fire. In: McKell, Cyrus M.;
       Blaisdell, James P.; Goodin, Joe R., eds. Wildland shrubs--their biology
       and utilization: Proceedings of a symposium; 1971 July; Logan, UT. Gen.
       Tech. Rep. INT-1. Ogden, UT: U.S. Department of Agriculture, Forest
       Service, Intermountain Forest and Range Experiment Station: 204-217. 
       [2611]

.  Wright, Henry A.; Neuenschwander, Leon F.; Britton, Carlton M. 1979. The
       role and use of fire in sagebrush-grass and pinyon-juniper plant
       communities: A state-of-the-art review. Gen. Tech. Rep. INT-58. Ogden,
       UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest
       and Range Experiment Statio. 48 p.  [2625]

.  Young, Richard P. 1983. Fire as a vegetation management tool in
       rangelands of the Intermountain Region. In: Monsen, Stephen B.; Shaw,
       Nancy, compilers. Managing Intermountain rangelands--improvement of
       range and wildlife habitats: Proceedings; 1981 September 15-17; Twin
       Falls, ID; 1982 June 22-24; Elko, NV. Gen. Tech. Rep. INT-157. Ogden,
       UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest
       and Range Experiment Station: 18-31.  [2681]

Related categories for Species: Tetradymia glabrata | Littleleaf Horsebrush