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.
Regularity: Regularly occurring
Occurrence in North America
Brittle bush 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 .
Regional Distribution in the Western United States
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
[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 . 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 . The flowering heads are
loosely clustered on long naked branchlets [1,35]. Brittle bush is
short lived. On permanent plots in the Sonoran Desert, the maximum
observed longevity was 32 years .
Brittle bush generally has shallow roots . One study found that the
root system of brittle bush on a north-facing slope was composed of a
stout taproot and numerous laterals. All laterals bore groups of
filamentous roots .
Mojave Desert Habitat
This taxon is found in the Mojave Desert, the smallest of the four North American deserts. While the Mojave lies between the Great Basin Shrub Steppe and the Sonoran Desert, its fauna is more closely allied with the lower Colorado division of the Sonoran Desert. Dominant plants of the Mojave include Creosote Bush (Larrea tridentata), Many-fruit Saltbush (Atriplex polycarpa), Brittlebush (Encelia farinosa), Desert Holly (Atriplex hymenelytra), White Burrobush (Hymenoclea salsola), and Joshua Tree (Yucca brevifolia), the most notable endemic species in the region.
The Mojave’s warm temperate climate defines it as a distinct ecoregion. Mojave indicator species include Spiny Menodora (Menodora spinescens), Desert Senna (Cassia armata), Mojave Indigobush (Psorothamnus arborescens), and Shockley's Goldenhead (Acamptopappus shockleyi). The Mojave supports numerous species of cacti, including several endemics, such as Silver Cholla (Opuntia echinocarpa), Mojave Prickly Pear (O. erinacea), Beavertail Cactus (O. basilaris), and Cotton-top Cactus (Echinocactus polycephalus).
While the Mojave Desert is not so biologically distinct as the other desert ecoregions, distinctive endemic communities occur throughout. For example, the Kelso Dunes in the Mojave National Preserve harbor seven species of endemic insects, including the Kelso Dunes Jerusalem Cricket (Ammopelmatus kelsoensis) and the Kelso Dunes Shieldback Katydid (Eremopedes kelsoensis). The Mojave Fringe-toed Lizard (Uma Scoparia), while not endemic to the dunes, is rare elsewhere. Flowering plants also attract butterflies such as the Mojave Sooty-wing (Pholisora libya), and the widely distributed Painted Lady (Vanessa cardui).
There are a total of eight amphibian species present in the Mojave Desert all of which are anuran species: the endemic Relict Leopard Frog (Lithobates onca); the endemic Amargosa Toad (Anaxyrus nelsoni); Lowland Leopard Frog (Lithobates yavapaiensis); Red-spotted Toad (Anaxyrus punctatus); Southwestern Toad (Anaxyrus microscaphus); Great Basin Spadefoot (Spea intermontana); Great Plains Toad (Anaxyrus cognatus); and the Pacific Treefrog (Pseudacris regilla).
The native range of California’s threatened Desert Tortoise (Gopherus agassizii) includes the Mojave and Colorado Deserts. The Desert Tortoise has adapted for arid habitats by storing up to a liter of water in its urinary bladder. The following reptilian fauna are characteristic of the Mojave region in particular: Gila Monster (Heloderma suspectum NT); Western Banded Gecko (Coleonyx variegatus), Northern Desert Iguana (Dipsosaurus dorsalis), Western Chuckwalla (Sauromalus obesus), and regal horned lizard (Phrynosoma solare). Snake species include the Desert Rosy Boa (Charina trivirgata gracia), Mojave Patchnose Snake (Salvadora hexalepis mojavensis), and Mojave Rattlesnake (Crotalus scutulatus).
Endemic mammals of the ecoregion include the Mojave Ground Squirrel (Spermophilus mohavensis) and Amargosa Vole (Microtus californicus scirpensis); and the California Leaf-nosed Bat (Macrotus californicus).
Key Plant Community Associations
Brittle bush 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, brittle bush 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 brittle bush. On other sites in this area,
brittle bush often codominants with creosotebush (Larrea tridentata) and
teddy-bear cholla (Opuntia bigelovii) . Brittle bush is also
codominant in the brittle bush-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" .
Brittle bush 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
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
More info for the term: cactus
K023 Juniper - pinyon woodland
K024 Juniper steppe woodland
K030 California oakwoods
K034 Montane chaparral
K035 Coastal sagebrush
K040 Saltbush - greasewood
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
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):
FRES28 Western hardwoods
FRES30 Desert shrub
FRES33 Southwestern shrubsteppe
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
FRES40 Desert grasslands
mesas . In the Sonoran Desert brittle bush is common on
south-facing, granitic slopes, volcanic slopes, upland flats, and
alluvial flats . In coastal sage scrub brittle bush grows on soils
derived from alluvial deposits, sandstone, granite and diorite . It
also grows on desert pavement . Brittle bush grows poorly on clay
soils . It occurs at elevations up to 3,000 feet (915 m)
Brittle bush 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
brittle bush areas receiving most of the rain in winter, and other areas
receiving mostly summer rain .
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
72 Southern scrub oak
239 Pinyon - juniper
241 Western live oak
255 California coast live oak
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. Brittle bush is a good colonizer after fire. Fires in
creosotebush scrub have resulted in an increase in brittle bush
frequency and density. Recent fires have converted creosotebush scrub
at Palm Springs to brittle bush coastal sage scrub similar in
composition to the stands covering semiarid interior valleys around
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,
Broad-scale Impacts of Plant Response to Fire
species in communities that include brittle bush:
Plant Response to Fire
Brittle bush wind-dispersed seeds readily invade postfire environments
and often become well established [7,22]. Following prescribed fires in
the upper Sonoran Desert, brittle bush 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 . In southern California
coastal sage scrub, fires were followed by rapid brittle bush seedling
establishment. Brittle bush accounted for most of the seedlings
observed during the first growing season. Recent fires have converted
cresotebush scrub at Palm Springs, California, to brittle bush coastal
sage scrub .
Brittle bush is categorized as a weakly-sprouting species [7,26]. Three
to five growing seasons after fire in creosotebush scrub, brittle bush
sprouting was rare . Following a June 15, 1981 wildfire in coastal
sage scrub, only 4 to 30 percent of the top-killed brittle bush shrubs
regenerated by crown sprouting. Maximum sprouting occurred on
north-facing slopes. The likelihood of brittle bush 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 . However, 1 year
after a hot, summer fire in Sonora, Mexico, surviving brittle bush
plants sprouted vigorously .
Postfire brittle bush 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 brittle bush density was less than 4 percent of prefire
density. More than 90 percent of the regeneration consisted of
Immediate Effect of Fire
all brittle bush plants in a coastal sage scrub community were
top-killed or killed by a June 1981 fire . Following a fast-moving,
low-severity fire in creosotebush scrub, brittle bush plants were mostly
scorched. Only leaves and branches near the ground burned, leaving
foliage on ultimate stems. However, brittle bush suffered 93 percent
mortality . A hot summer fire in Sonora, Mexico, killed 32 percent
of mature brittle bush 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 .
Initial-offsite colonizer (off-site, initial community)
Small shrub, adventitious-bud root crown
Brittle bush 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 .
Brittle bush does not accumulate organic material and windblown soil
beneath its crown, as do multiple-stemmed shrubs . Recurrent fires
select for short-lived desert shrubs such as brittle bush at the expense
of long-lived species .
More info for the terms: cover, density
Facultative Seral Species
Brittle bush 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 brittle bush
community may persist for decades . In permanent plots in the
Sonoran Desert, brittle bush density and cover was more or less stable
over 72 years. However, only 17 percent of seedlings survived to the
seventh year .
Sexual reproduction - Brittle bush reproduces almost exclusively by seed
[7,45]. Seeds are dispersed long distances by wind. Brittle bush often
germinates prolifically after heavy winter rains . Plants are not
frost tolerant, and frost may damage leaves and stems .
Reproduction may be reduced by interspecific competition. Growth and
productivity of brittle bush is limited by the low precipitation in its
native habitat. Neighboring brittle bush further decrease water availability,
reducing brittle bush productivity .
Vegetative reproduction - Brittle bush can sprout from the root crown
Brittle bush is allelopathic. The leaves produce a toxic, water-soluble
substance that inhibits the growth of several winter annuals .
Growth Form (according to Raunkiær Life-form classification)
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.
Life History and Behavior
More info for the terms: density, resistance
Brittle bush leaves and flowers are formed whenever the water relations
are favorable . This can occur any time from November through May
. Under extreme drought conditions brittle bush becomes dormant and
the leaves are shed [21,50]. Brittle bush 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 .
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Brittle bush infestation reduces forage production because brittle bush
competes strongly with buffelgrass (Cenchrus ciliarus). Several studies
were conducted to determine the effectiveness of mechanical and chemical
brittle bush 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 brittle bush. High intensity livestock grazing
reduced brittle bush growth, but caused no significant change in brittle
bush density after 3 years .
Relevance to Humans and Ecosystems
Picacho Mountains of Arizona in 1983 are as follows :
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 brittle bush has also been analyzed by Seegmiller
and others  and Rautenstrauch and others .
Other uses and values
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 brittle bush twigs as a remedy for toothaches. They also grind the
resin and sprinkle it on sores .
Value for rehabilitation of disturbed sites
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 . Brittle bush is used
to minimize erosion and sediment damage near highways in Arizona .
Importance to Livestock and Wildlife
sheep [19,48]. Brittle bush has no forage value for domestic livestock
. In a laboratory study, kangaroo rats ate brittle bush seeds, but
they were not preferred . Several species of breeding birds inhabit
the brittle bush-ironwood (Olneya tesota) community of foothills and
Encelia farinosa (commonly known as brittlebush or brittlebrush), is a common desert shrub of northwestern Mexico through California and the southwestern United States. Its common name comes from the brittleness of its stems.
Encelia farinosa can be found in a variety of habitats from dry gravelly slopes to open sandy washes up to 1,000 metres (3,300 ft). It does well in cultivation and recently has spread dramatically in areas not natural to its distribution in large part because Caltrans has begun to use it in hydroseeding.
Encelia farinosa grows up to 30 to 150 centimetres (12 to 59 in) tall, with fragrant leaves 3–8 cm long, ovate to deltoid, and silvery tomentose. The capitula are 3–3.5 cm in diameter, with orange-yellow ray florets and yellow or purple-brown disc florets. They are arranged in loose panicles above the leafy stems fruit 3–6 mm and there is no pappus.
Two varieties of E. farinosa are recognized:
- Encelia farinosa var. farinosa Gray ex. Torr.
- Encelia farinosa var. phenicodonta (Blake) I.M. Johnston
Varieties formerly included E. farinosa var. radians, now regarded as a separate species E. radians Brandegee.
Brittlebush has a long history of uses by indigenous and pioneer peoples.
- Glue: The resin collected from the base of the plant, yellowish to brown in color, can be heated and used as a glue. The O'odham and Seri use it for hafting, to hold points on arrows and harpoons.
- Sealer: A different sort of resin is collected from the upper stems, is more gummy and generally a clear yellow. The Seri use this to seal pottery vessels.
- Incense: Early Spanish friars learned that the resin made a highly fragrant incense, akin to frankincense in odor.
- Gum: The Sells area Tohono O'odham children use upper stem resin as a passable chewing gum.
- Toothbrush: Oldtime cowboys used brittlebush stem as a fine toothbrush. Simply select a largish branch and peel off the bitter bark, no need for toothpaste.
- Medicinal: Seri use brittlebush to treat toothache. For toothache the bark is removed, the branch heated in ashes, and then placed in the mouth to "harden" a loose tooth. The Cahuilla used brittlebush to treat toothaches as well, and used it as a chest pain reliever by heating the gum and applying it to the chest.
- Felger, Richard Stephen; Moser, Mary Beck (1985). People of the Desert and Sea: Ethnobotany of the Seri Indians (2. print. ed.). Tucson, Ariz.: University of Arizona Press. ISBN 0816508186.
- Hogan, C. Michael (ed.) Brittlebush – Encelia farinosa at the Encyclopedia of Life. Accessed 1 April 2013.
- Gray, Reed; Bonner, James (19 March 1948). "Structure Determination and Synthesis of a Plant Growth Inhibitor, 3-Acetyl-6-methoxybenzaldehyde, Found in the Leaves of Encelia Farinosa". Journal of the American Chemical Society 70 (3): 1249–1253. doi:10.1021/ja01183a114. PMID 18909201.
- Bohm, Bruce A. (2009). The Geography of Phytochemical Races. Dordrecht: Springer. p. 112. ISBN 9781402090523.
- Dunmire, William W. (2004). Gardens of New Spain: How Mediterranean Plants and Foods Changed America. Austin: University of Texas Press. ISBN 978-0-292-70564-7.
- "Cahuilla Plants". www.enduringknowledgepublications.com. Enduring Knowledge Publications. Retrieved 2012.
- "Temalpakh Ethnobotanical Garden". www.malkimuseum.org. Retrieved 2007.
Names and Taxonomy
white brittle bush
farinosa Gray ex. Torr. [1,35,46]. There are three recognized varieties
Encelia farinosa var. farinosa
Encelia farinosa var. phenicodonta (Blake) I. M. Johnston
Encelia farinosa var. radians Brandegee ex. Blake
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