Brittlebush

Plants of Encelia farinosa with brown-purple disc corollas, found along the Colorado and Salt rivers, and common in Baja California, are var. phenicodonta. Plants with substrigose leaves, capitulescences branched toward bases rather than distally, and ray florets reduced in both size and number are most often hybrids and backcrosses between E. farinosa and E. frutescens. P. A. Munz (1959) indicated that I. L. Wiggins had reported var. radians Brandegee ex S. F. Blake as occurring in southeastern California; that variety is known only from Baja California.

Shrubs, 30–150 cm (sap fragrant). Stems branched distally, tomentose, developing smooth barks. Leaves cauline (clustered near stem tips); petioles 10–20 mm; blades silver or gray, ovate to lanceolate, 20–70 mm, apices obtuse or acute, faces tomentose. Heads in paniculiform arrays (branching among heads mainly distal). Peduncles glabrous except near heads (± yellow). Involucres 4–10 mm. Phyllaries lanceolate. Ray florets 11–21; corolla laminae 8–12 mm. Disc corollas yellow or brown-purple, 5–6 mm. Cypselae 3–6 mm; pappi 0. 2n = 36.

Encelia farinosa var. phenicodonta S. F. Blake) I. M. Johnston

Encelia farinosa has a bioregional distribution that includes California's eastern South Coast and adjacent Peninsular Ranges, as well as a desert distribution outside California to southwestern Utah, Arizona and northwest Mexico. The occurrences are restricted to elevations less than 1000 meters. Chief habitats are in coastal scrub and on stony desert hillsides.

This desert shrub, also known by the common name Brittlebush, reaches a height of 30 to 150 centimeters, manifesting a single or several trunks. The stems are much-branched above, with young stems tomentose; older stems exhibit smooth bark, This plant's sap is fragrant Leaves are clustered near stem tips, with leaf petioles 10 to 20 millimeters in length, and with ovate to lanceolate blades ranging from two to seven cm. These tomentose leaves are silver or gray in color. Inflorescence heads are radiate, and generally yellowish, although the disk flowers can be yellow or brownish-purple.

The brittle bush is a medium sized rounded shrub, that belongs to the sunflower family. It has long, oval, silver gray leaves that are fuzzy. The fuzziness acts like a blanket for the cold weather. The branches are brittle and woody which have a certain fragrance. The plant is fairly sensitive, and it likes to grow on rocky hillsides, dry slopes, and washes. They will typically be found on foothills of a mountain.

In the past, the brittlebush was used by the native Americans as a type of glue or toothpaste. They would also sprinkle the paste on sores or head it on their bodies to relieve pain. The wildlife of the desert use it also. Deer, and desert bighorn sheep graze on it, and the kangaroo rat likes to munch on its seeds.

More info for the term: shrubland

This fire study provides information on postfire responses of plant
species in communities that include brittlebush:

• Research Project Summary: Effects of June fires in shrubland converted
  to buffelgrass pasture in Sonora, Mexico

brittlebush
inceinso
white brittlebush

More info for the term: shrub

Brittlebush is a native, drought-deciduous, perennial shrub
[7,8,21,28].  It grows to about 5 feet (1.5 m).  It has a woody base and
is rounded and much-branched in form.  Thick branches support an
umbrella of leaves with few stems beneath [7].  The leaves are 0.7 to 2
inches (2-5 cm) long and 0.6 to 1 inch (1.5-2.5 cm) broad.  They are
mostly located toward the end of branches [35].  The flowering heads are
loosely clustered on long naked branchlets [1,35].  Brittlebush is
short lived.  On permanent plots in the Sonoran Desert, the maximum
observed longevity was 32 years [54].



Brittlebush flowers. Wikimedia Commons image by Stan Shebs.


Brittlebush generally has shallow roots [27].  One study found that the
root system of brittlebush on a north-facing slope was composed of a
stout taproot and numerous laterals.  All laterals bore groups of
filamentous roots [8].

More info for the term: adventitious

Brittlebush grows in the interior valleys of coastal southern
California (San Bernardino Valley, Lake Elsinore, western San Diego
County, and west Riverside County), Baja California, southern Nevada in
Clark County, southwestern Utah, southern and western Arizona, and
northwestern Mexico [1,35,46,52].  It is adventitious in Hawaii [55].



Distribution of brittlebush in the United States. Map courtesy of USDA, NRCS. 2018. The PLANTS Database.
National Plant Data Team, Greensboro, NC [2018, July 6] [41].

More info for the terms: root crown, shrubs

Brittlebush is a good initial offsite colonizer of postfire communities
via wind dispersed seeds [7,22,26].  It also has some ability to sprout
from the root crown, which may be limited by intolerance of heat [45].
Brittlebush does not accumulate organic material and windblown soil
beneath its crown, as do multiple-stemmed shrubs [49].  Recurrent fires
select for short-lived desert shrubs such as brittlebush at the expense
of long-lived species [7].

More info for the terms: cactus, cover, density, fire management, forest, frequency, herb, herbaceous, sclerophyllous, series, shrubs

NO-ENTRY

FIRE CASE STUDY
SPECIES: Encelia farinosa
FIRE CASE STUDY CITATION :
Tesky, Julie L., compiler. 1993. Brittlebush response to fire in creosotebush scrub
of the Sonora Desert, California. In: Encelia farinosa. In: Fire Effects
Information System, [Online]. U.S. Department of Agriculture, Forest
Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
Available: https://www.fs.fed.us/database/feis/ [
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REFERENCE :
Brown, David E.; Minnich, Richard A. 1986. Fire and changes in creosote
bush scrub of the western Sonoran Desert, California. American Midland
Naturalist. 116(2): 411-422. [7].


SEASON/SEVERITY CLASSIFICATION :
Beginning in 1978, a series of fires spread through dried herbaceous
fuels into extensive areas of creosotebush (Larrea tridentata) scrub.  The
flames reduced the herb layer to a low stubble, indicative of
fast-moving, low-intensity fires.  Fires occurred in June, July, August,
or September.


STUDY LOCATION :
Four sites, on Quaternary alluvial fans descending from the east scarp of
the San Jacinto Mountains at the end of the Coachella Valley near Palm
Springs, California, were chosen for study.  The four sites were located
at the fire boundaries on the Chino, Blaisdell, and Palm canyon alluvial
fans in order to compare burned vegetation with adjacent unburned
stands.

Fires occurred in the Chino Canyon fan (1,250 acres [500 ha], 1978),
Blaisdell and Chino canyons (6,900 acres [2800 ha], 1980), and the east
scarp and alluvial fans below 3,200 acres (1,300 m) from Chino Canyon to
Palm Canyon (15,000 acres [6,000 ha], 1980).  A 3,000 acre (1,200 ha)
fire in 1982 overlapped large areas burned in 1973 near Snow Creek.  In
1983, the first of three fires reburned portions of the Snow Creek area
and Blaisdell Canyon.  Two smaller fires also occurred along Snow Creek
road and Interstate 10.


PREFIRE VEGETATIVE COMMUNITY :
Most of the Sonoran Desert is covered with creosotebush scrub consisting
of scattered low shrubs less than 6.6 feet (2 m).  Representative growth
forms include evergreen sclerophyllous and deciduous shrubs, subligneous
subshrubs, leaf and stem succulents, and annual herbs.  Bajadas and
adjacent mountainsides in the Coachella Valley are covered by
creosotebush, brittlebush (Encelia farinosa), big galleta (Hilaria
rigida), hedgehog cactus (Echinocereus engelmannii), and Grays ratany
(Krameria grayi).

Vegetation on the plains and lower bajadas, including the study sites,
is dominated by creosotebush, white bursage (Ambrosia dumosa), and
brittlebush, which may form 60 to 100 percent of total vegetation
cover.  Blue paloverde (Cercidium floridum), ironwood (Olynea tesota),
smoketree (Dalea spinosa), beloperone (Beloperone californica), and
desert lavender (Hyptis emoryi) are common along washes.  Succulents
such as Ferocactus acanthodes, hedgehog cactus, beavertail cactus
(Opuntia basilaris), teddy-bear cholla (O. bigelovii), and golden cholla
(O. echinocarpa) reach maximum densities on sandy hillsides and bajadas
with rocky, gravelly, or sandy substrates.


TARGET SPECIES PHENOLOGICAL STATE :
The phenological state of brittlebush at the time of the fires is
unknown.  The areas were surveyed between April 25 and May 27 1983, when
brittlebush was in full growth or flower.


SITE DESCRIPTION :
The climate of the Coachella Valley is extremely arid.  Average annual
rainfall at Palm Springs is 5.4 inches (138 mm).  Summers are hot and
dry, although there are occasional thunderstorms, mostly over the nearby
mountains.  Coarse-textured soils are well-drained and moderately
alkaline, with a minimum of organic matter.  No information was given as
to the specific topography, slope, and elevation of each site.


FIRE DESCRIPTION :
The fires in creosotebush scrub characteristically spread during periods
when ambient temperatures averaged 95 to 104 degrees Fahrenheit (35-40
deg C) and relative humidity ranged from 10 to 25 percent.  High winds
were caused by the typical spring and early summer gravity acceleration
of descending coastal marine air spilling through San Gorgonio Pass.
Upcanyon winds and nocturnal air drainage promoted fire spread on the
eastern face of Mt. San Jacinto.  The flames reduced the herb layer to a
low stubble, indicative of fast-moving, low-intensity fires.


FIRE EFFECTS ON TARGET SPECIES :
The vegetation was sampled three growing seasons after fires at
Blaisdell, Palm Canyon and Palm Indian sites and five growing seasons
after fire at the Chino site.  Brittlebush plants were mostly scorched.
Only leaves and branches near the ground burned, leaving foliage on
higher stems.  However, brittlebush suffered 93 percent mortality.

None of the severely burned brittlebush plants resprouted after fire;
16 percent of the scorched plants resprouted.  Brittlebush accounted
for most of the seedlings observed during the first growing season.  The
wet 1982-1983 season was followed by abundant reproduction of brittle
bush in both burned and unburned sites.  After 3 to 5 growing seasons,
the total cover in burned sites was about half that of unburned sites
and was composed mostly of brittlebush.

Density (D) and cover (C) of established (unburned) and resprouting
(burned) brittlebush at two sites in the Sonoran Desert, California,
are shown below.  Density is expressed in number of plants per 100
meters square.  Cover is expressed as percent ground covered.

                 unburned      burned
                  D     C      D    C   
Chino           11.5   9.2    1.5  2.0 
Palm Canyon     13.0  10.6    2.0  2.6
Palm Indian      3.0   1.4    2.5  3.5
Blaisdell        1.0   0.9    0.0  0.0

Brittlebush seedling density (number/ha) in initial and subsequent
growing seasons was:
       
        1980-1981    1981-1983

Burned   1,460         7,010 
Unburned    90         5,650


FIRE MANAGEMENT IMPLICATIONS :
Fires are infrequent in the Sonoran Desert owing to limited biomass,
wide spacing between shrubs and sparse ground cover.  Successional
studies in creosotebush scrub reveal postdisturbance recolonization by
long-lived species is very slow and may require hundreds of years.
Fires may have long-term impacts on the structure and composition of
this community.  Brittlebush is a good colonizer after fire.  Fires in
creosotebush scrub have resulted in an increase in brittlebush
frequency and density.  Recent fires have converted creosotebush scrub
at Palm Springs to brittlebush coastal sage scrub similar in
composition to the stands covering semiarid interior valleys around
Riverside, California.

More info for the terms: cover, density, frequency, shrubs

Fires are infrequent in the Sonoran Desert owing to limited biomass,
wide spacing between shrubs and sparse ground cover.  Successional
studies in creosotebush scrub reveal postdisturbance recolonization by
long-lived species is very slow and may require hundreds of years.
Fires may have long-term impacts on the structure and composition of
this community.  Brittlebush is a good colonizer after fire.  Fires in
creosotebush scrub have resulted in an increase in brittlebush
frequency and density.  Recent fires have converted creosotebush scrub
at Palm Springs to brittlebush coastal sage scrub similar in
composition to the stands covering semiarid interior valleys around
Riverside, California.

More info on this topic.

More info for the term: phanerophyte

  
   Phanerophyte

Brittlebush is commonly found on dry, rocky or gravelly slopes and
mesas [1].  In the Sonoran Desert brittlebush is common on
south-facing, granitic slopes, volcanic slopes, upland flats, and
alluvial flats [44].  In coastal sage scrub brittlebush grows on soils
derived from alluvial deposits, sandstone, granite and diorite [44].  It
also grows on desert pavement [33].  Brittlebush grows poorly on clay
soils [16].  It occurs at elevations up to 3,000 feet (915 m)
[38,46,47].

Brittlebush is restricted to climates with long periods of limited
moisture.  The total amount of precipitation in these areas is quite
variable.  The seasonal pattern of rainfall is also variable, with some
brittlebush areas receiving most of the rain in winter, and other areas
receiving mostly summer rain [50].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

    68  Mesquite
    72  Southern scrub oak
   239  Pinyon - juniper
   241  Western live oak
   242  Mesquite
   255  California coast live oak

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

More info for the term: shrub

   FRES28  Western hardwoods
   FRES29  Sagebrush
   FRES30  Desert shrub
   FRES33  Southwestern shrubsteppe
   FRES34  Chaparral - mountain shrub
   FRES35  Pinyon - juniper
   FRES40  Desert grasslands

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: cactus, shrub, woodland

   K023  Juniper - pinyon woodland
   K024  Juniper steppe woodland
   K030  California oakwoods
   K033  Chaparral
   K034  Montane chaparral
   K035  Coastal sagebrush
   K040  Saltbush - greasewood
   K041  Creosotebush
   K042  Creosotebush - bursage
   K043  Paloverde - cactus shrub
   K044  Creosotebush - tarbush
   K053  Grama - galleta steppe
   K054  Grama - tobosa prairie
   K055  Sagebrush steppe
   K056  Wheatgrass - needlegrass shrubsteppe
   K057  Galleta - three-awn shrubsteppe
   K058  Grama - tobosa shrubsteppe
   K061  Mesquite - acacia savanna
   K064  Grama - needlegrass - wheatgrass
   K065  Grama - buffalograss
   K087  Mesquite - oak savanna

More info for the term: low-severity fire

Brittlebush is often top-killed or completely killed by fire.  Nearly
all brittlebush plants in a coastal sage scrub community were
top-killed or killed by a June 1981 fire [26].  Following a fast-moving,
low-severity fire in creosotebush scrub, brittlebush plants were mostly
scorched.  Only leaves and branches near the ground burned, leaving
foliage on ultimate stems.  However, brittlebush suffered 93 percent
mortality [7].  A hot summer fire in Sonora, Mexico, killed 32 percent
of mature brittlebush plants and 60 percent of seedlings.  Burning in 2
consecutive years killed 70 percent of mature plants and 90 percent of
seedlings.  The remaining plants were injured and had not recovered
after 3 years [53].

Brittlebush is a browse species of desert mule deer and desert bighorn
sheep [19,48].  Brittlebush has no forage value for domestic livestock
[15].  In a laboratory study, kangaroo rats ate brittlebush seeds, but
they were not preferred [23].  Several species of breeding birds inhabit
the brittlebush-ironwood (Olneya tesota) community of foothills and
bajadas [17].

More info for the terms: association, codominant, shrub

Brittlebush occurs in pine-oak (Pinus-Quercus) and open oak woodlands,
semidesert and desert grasslands, desert scrub, and coastal sage scrub.
Throughout most of its range, brittlebush is the dominant shrub.  It
forms extensive monospecific stands in many areas.  On south-facing
slopes and bajadas of the lower Colorado Valley in the Sonoran Desert,
vegetation is dominated by brittlebush.  On other sites in this area,
brittlebush often codominants with creosotebush (Larrea tridentata) and
teddy-bear cholla (Opuntia bigelovii) [51].  Brittlebush is also
codominant in the brittlebush-wishbonebush (Mirabilis laevis)
association, which usually occurs in coastal sage scrub on south-facing
moderately, steep slopes.  The publication describing this association is
"The community composition of California coastal sage scrub" [18].

Brittlebush is often associated with palo verde (Cercidium spp.),
saguaro (Carnegiea gigantea), fairy duster (Calliandra eriophylla),
Janusia graciles, agave (Agave spp.), creosotebush, Anderson wolfberry
(Lycium andersonii), white bursage (Ambrosia dumosa), canyon ragweed
(Ambrosia ambrosioides), Opuntia spp., whitethorn acacia (Acacia
constricta), catclaw acacia (A. greggii), fourwing saltbush (Atriplex
canescens), desert hackberry (Celtis pallida), honey mesquite (Prosopis
glandulosa var. glandulosa), and several species of perennial bunchgrass
[4,14,15,28,29].

More info for the term: shrub

Shrub

More info for the term: density

Brittlebush infestation reduces forage production because brittlebush
competes strongly with buffelgrass (Cenchrus ciliarus).  Several studies
were conducted to determine the effectiveness of mechanical and chemical
brittlebush control.  Mowing killed few plants but temporarily reduced
growth.  Hand removal resulted in 100 percent mortality, but brittle
bush seedlings rapidly reinvaded and densities were equal to
pretreatment levels after 3 months.  Soil-applied pelleted tebuthiuron
and picloram control brittlebush.  High intensity livestock grazing
reduced brittlebush growth, but caused no significant change in brittle
bush density after 3 years [53].

Nutritional values of brittlebush collected bimonthly in the
Picacho Mountains of Arizona in 1983 are as follows [19]:
                                      Fiber %
        Dry Matter %   Protein %     ADF    NDF      Lignin %
  
Jan-Feb   36.86         11.04       22.31  30.36     5.48
Mar-Apr   38.23         9.28        20.67  28.86     5.87
May-June  49.56         8.49        28.74  38.98     8.08
July-Aug  72.02         3.28        48.72  63.88     13.64
Sept-Oct  38.28         8.60        28.28  34.84     7.60
Nov-Dec   31.84         12.70       26.11  31.27     8.74

ADF-acid detergent fiber
NDF-nonacid detergent fiber

Nutritional value of brittlebush has also been analyzed by Seegmiller
and others [48] and Rautenstrauch and others [33].

     AZ  CA  HI  NV  UT  MEXICO

The stems of brittlebush exude a clear resin used by the Indians as
glue and chewing gum.  In the churches of some parts of Mexico the resin
is burned as incense [1,46].  The Seri Indians of Sonora, Mexico, use
the brittlebush twigs as a remedy for toothaches.  They also grind the
resin and sprinkle it on sores [12].

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More info for the term: density

Brittlebush leaves and flowers are formed whenever the water relations
are favorable [8].  This can occur any time from November through May
[35].  Under extreme drought conditions brittlebush becomes dormant and
the leaves are shed [21,50].  Brittlebush also shows seasonal variation
in leaf density and thickness.  During times of available water, leaves
expand more, are less pubescent, are less capable of reducing water
loss, and have lower resistance to carbon dioxide flux.  These
characteristics are reversed as soil water decreases and the more
mesophytic leaves abscise [50].

More info for the terms: density, seed, shrubs, wildfire, xeric

Brittlebush wind-dispersed seeds readily invade postfire environments
and often become well established [7,22].  Following prescribed fires in
the upper Sonoran Desert, brittlebush underwent an initial 83 percent
reduction in density, but within 9 months it increased to 762 percent of
preburn density.  This was a result of very successful seed germination
and subsequent seedling establishment [9].  In southern California
coastal sage scrub, fires were followed by rapid brittlebush seedling
establishment.  Brittlebush accounted for most of the seedlings
observed during the first growing season.  Recent fires have converted
cresotebush scrub at Palm Springs, California, to brittlebush coastal
sage scrub [7].

Brittlebush is categorized as a weakly-sprouting species [7,26].  Three
to five growing seasons after fire in creosotebush scrub, brittlebush
sprouting was rare [7].  Following a June 15, 1981 wildfire in coastal
sage scrub, only 4 to 30 percent of the top-killed brittlebush shrubs
regenerated by crown sprouting.  Maximum sprouting occurred on
north-facing slopes.  The likelihood of brittlebush recovery from fire
by sprouting is greater on cool, less xeric sites where fires are often
less severe, and less on the hot, xeric sites [26].  However, 1 year
after a hot, summer fire in Sonora, Mexico, surviving brittlebush
plants sprouted vigorously [53].

Postfire brittlebush densities for east and west exposures 1.5 years
after a June coastal sage scrub fire were 79 to 205 percent of prefire
densities on east, south, and west exposures.  On north-facing slopes,
postfire brittlebush density was less than 4 percent of prefire
density.  More than 90 percent of the regeneration consisted of
seedlings [26].

More info for the term: shrub

   Initial-offsite colonizer (off-site, initial community)
   Small shrub, adventitious-bud root crown

More info for the terms: competition, root crown, seed

Sexual reproduction - Brittlebush reproduces almost exclusively by seed
[7,45].  Seeds are dispersed long distances by wind.  Brittlebush often
germinates prolifically after heavy winter rains [7].  Plants are not
frost tolerant, and frost may damage leaves and stems [39].

Reproduction may be reduced by interspecific competition.  Growth and
productivity of brittlebush is limited by the low precipitation in its
native habitat.  Neighboring brittlebush further decrease water availability,
reducing brittlebush productivity [51].

Vegetative reproduction - Brittlebush can sprout from the root crown
[7,26].

Brittlebush is allelopathic.  The leaves produce a toxic, water-soluble
substance that inhibits the growth of several winter annuals [24].

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

    3  Southern Pacific Border
    7  Lower Basin and Range
   12  Colorado Plateau

More info for the terms: herb, herbaceous, series

Beginning in 1978, a series of fires spread through dried herbaceous
fuels into extensive areas of creosotebush (Larrea tridentata) scrub.  The
flames reduced the herb layer to a low stubble, indicative of
fast-moving, low-intensity fires.  Fires occurred in June, July, August,
or September.

The climate of the Coachella Valley is extremely arid.  Average annual
rainfall at Palm Springs is 5.4 inches (138 mm).  Summers are hot and
dry, although there are occasional thunderstorms, mostly over the nearby
mountains.  Coarse-textured soils are well-drained and moderately
alkaline, with a minimum of organic matter.  No information was given as
to the specific topography, slope, and elevation of each site.

More info on this topic.

More info for the terms: cover, density

Facultative Seral Species

Brittlebush usually occurs in initial and early seres [7,31,34,42]. It
is an early colonizer of disturbed sites, often replacing long-lived
perennials in postfire communities [7,31,34,40].  An open brittlebush
community may persist for decades [7].  In permanent plots in the
Sonoran Desert, brittlebush density and cover was more or less stable
over 72 years.  However, only 17 percent of seedlings survived to the
seventh year [54].

Encelia farinosa var. farinosa
Encelia farinosa var. phenicodonta (Blake) I. M. Johnston
Encelia farinosa var. radians Brandegee ex. Blake

The currently accepted scientific name for brittlebush is Encelia
farinosa Gray ex. Torr. [1,35,46].

Brittlebush is most valuable for rehabilitating low maintenance
landscapes, critical stabilization areas, and disturbed areas.  It is
easily transplanted or can be established by direct seeding.  Seeds and
plants are available in limited quantities [38].  Brittlebush is used
to minimize erosion and sediment damage near highways in Arizona [6].

Encelia farinosa (commonly known as brittlebush, brittlebrush, or incienso), is a common desert shrub of the southwestern United States and northern Mexico. It has a variety of historical uses.