Gutierrezia Microcephala
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''Gutierrezia microcephala'' is a species of flowering plant in the family
Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...
known by the common names sticky snakeweed, threadleaf snakeweed, threadleaf broomweed, and smallhead snakeweed. It is a
subshrub A subshrub (Latin ''suffrutex'') or undershrub is either a small shrub (e.g. prostrate shrubs) or a perennial that is largely herbaceous but slightly woody at the base (e.g. garden pink and florist's chrysanthemum). The term is often interch ...
native to the southwestern United States and northern Mexico, and can be found in arid
grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...
and desert sand
dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...
habitats. It can be toxic to livestock in large quantities, due to the presence of
saponin Saponins (Latin ''sapon'', 'soap' + ''-in'', 'one of') are bitter-tasting, usually toxic plant-derived secondary metabolites. They are organic chemicals that become foamy when agitated in water and have high molecular weight. They are present ...
s and high concentrations of
selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
.


Botanical description

''Gutierrezia microcephala'' is a small,
resin A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...
ous,
perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...
desert subshrub that is typically in height and less than in diameter. It is heavily branched, often causing it to be nearly spherical. New shoots and twigs are green to yellow in color, and older parts are brown and woody. The leaves are linear, threadlike, and alternate; long and wide. Along with the leaves, the stem tissue is
photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...
, giving the plant a high
photosynthetic capacity Photosynthetic capacity (Amax) is a measure of the maximum rate at which leaves are able to fix carbon during photosynthesis. It is typically measured as the amount of carbon dioxide that is fixed per metre squared per second, for example as μm ...
. ''G. microcephala'' typically flowers July to October, but this can vary depending on the amount of precipitation. When flowering, the tips of stem branches are occupied by
sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s of 5 or 6 flowers. The knobby, waxy yellow flower
bud In botany, a bud is an undeveloped or Plant embryogenesis, embryonic Shoot (botany), shoot and normally occurs in the axil of a leaf or at the tip of a Plant stem, stem. Once formed, a bud may remain for some time in a dormancy, dormant conditi ...
s open into golden yellow
flower heads A pseudanthium (; : pseudanthia) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers ...
, each of which has one or two disc florets between in diameter, and one or two ray florets between in diameter. The mature plants produce many
achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...
, although most seeds fall within a few metres of the parent plant. This is because the plant grows a very small pappus, which makes wind-borne seed distribution very inefficient.


Habitat

''Gutierrezia microcephala'', a native North American plant, is found throughout the southwestern United States (from
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
east as far as
Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
and
Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...
) and northern Mexico (from
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
to
Tamaulipas Tamaulipas, officially the Free and Sovereign State of Tamaulipas, is a state in Mexico; one of the 31 states which, along with Mexico City, comprise the 32 federal entities of Mexico. It is divided into 43 municipalities. It is located in nor ...
,
Veracruz Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entit ...
, and
Zacatecas Zacatecas, officially the Free and Sovereign State of Zacatecas, is one of the Political divisions of Mexico, 31 states of Mexico. It is divided into Municipalities of Zacatecas, 58 municipalities and its capital city is Zacatecas City, Zacatec ...
). It occurs in a variety of
ecoregion An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...
s, such as arid grasslands,
chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...
, sand dunes, and oak or oak-pine
woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...
s. ''G. microcephala'' is primarily found in well-drained sandy, gravelly, or rocky soils, and is often found in intermittently dry creeks or on the adjacent slopes. It often predominates on shallow, rocky soil, where grasses are not well established.


Uses

''Gutierrezia microcephala'' was used by the Native Americans for various reasons. The
Cahuilla The Cahuilla, also known as ʔívil̃uqaletem or Ivilyuqaletem, are a Native Americans in the United States, Native American people of the various tribes of the Cahuilla Nation, living in the inland areas of southern California. ...
used an infusion of the plant as a gargle or placed the plant in their mouths as a toothache remedy. The
Hopi The Hopi are Native Americans who primarily live in northeastern Arizona. The majority are enrolled in the Hopi Tribe of Arizona and live on the Hopi Reservation in northeastern Arizona; however, some Hopi people are enrolled in the Colorado ...
and
Tewa The Tewa are a linguistic group of Pueblo people, Pueblo Native Americans in the United States, Native Americans who speak the Tewa language and share the Pueblo culture. Their homelands are on or near the Rio Grande in New Mexico north of San ...
both used the plant as a
carminative A carminative, known in Latin as carminativum (plural carminativa), is a herb or preparation intended to combat flatulence either by preventing formation of gas in the gastrointestinal tract or Name The word ''carminative'' is a derivative of Lat ...
, as
prayer stick A prayer stick is a stick-shaped object used for prayer. Background In the rituals of the Puebloan people of the American Southwest contain many prayers; thus the Zuñi have prayers for food, health, and rain. Prayer-sticks, that is sticks with ...
decorations, and for roasting sweet corn, and the
Navajo The Navajo or Diné are an Indigenous people of the Southwestern United States. Their traditional language is Diné bizaad, a Southern Athabascan language. The states with the largest Diné populations are Arizona (140,263) and New Mexico (1 ...
applied a poultice of the plant to the back and legs of horses for unknown reasons. The Zuni steeped the flower heads in boiling water and used the tea as a
diuretic A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics ...
, tonic, and sweat-inducer, and also used the plant as an indicator of water. ''Gutierrezia microcephala'' is of little known use to wildlife, and is generally uneaten by livestock except when other forage is unavailable.


Toxicity

''Gutierrezia microcephala'' can be toxic to livestock, especially when grown in sandy soil. Toxicity is due to the presence of saponins,
alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...
s,
terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predomi ...
s, and
flavonols Flavonols are a class of flavonoids that have the 3-hydroxyflavone backbone (IUPAC name: 3-hydroxy-2-phenylchromen-4-one). Their diversity stems from the different positions of the phenolic –OH groups. They are distinct from flavanols (with ...
, as well as high concentrations of selenium; ''G. microcephala'' plants have been found to contain selenium levels of 1287 ppm. Toxicity symptoms include abortion and death; as little as of fresh ''G. microcephala'' consumed by cattle in seven days can cause abortions, and in cattle, sheep, and goats consuming ten to twenty percent of their body weight in two weeks can cause death.


Management

''Gutierrezia microcephala'' is one of the most widespread and damaging
rangeland Rangelands are grasslands, shrublands, woodlands, wetlands, and deserts that are grazed by domestic livestock or wild animals. Types of rangelands include tallgrass and shortgrass prairies, desert grasslands and shrublands, woodlands, savanna ...
weeds, and is an indicator of
overgrazed Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature r ...
or disturbed rangelands. The herbicides
picloram Picloram is a systemic herbicide used for general woody plant control. It also controls a wide range of broad-leaved weeds, but most grasses are resistant.
and
triclopyr Triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) is an organic compound in the pyridine group that is used as a systemic foliar herbicide and fungicide. History Triclopyr triethylammonium (TEA) was first registered in 1979 in the United ...
have been found to give satisfactory control, with control lasting at least 5 to 7 years with proper grazing management. Biological control has also been studied, with a combination of an Argentinean root-boring weevil, ''Heilipodus ventralis'', and an Argentinean moth root-borer, '' Carmenta haematica'', found to be an effective method of control. Fire kills or severely damages ''G. microcephala'', allowing controlled burns to be used in the management of its populations. Burns must be done carefully, as ''G. microcephala'' may recolonize burned sites if moisture conditions and competition is favorable, giving mixed success for prescribed burns. Burns can be limited by insufficient amounts fine fuel; if there is enough fine fuel, burns are generally effective if fuel moisture and
relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...
are low, the air temperature is between , and there is a gentle breeze.


References


External links


USDA Plants Profile for ''Gutierrezia microcephala'' (threadleaf snakeweed)Calflora Database: ''Gutierrezia microcephala'' (Threadleaf snakeweed) Jepson Manual eFlora (TJM2) treatment of ''Gutierrezia microcephala''Tropicos.org: photo of herbarium specimen
— ''collected in Nuevo León (1978)''.
UC Photos gallery of ''Gutierrezia microcephala''
* {{Taxonbar, from=Q5621812 microcephala Flora of Northeastern Mexico Flora of Northwestern Mexico Flora of the Southwestern United States Flora of the South-Central United States Flora of the California desert regions Flora of Colorado Flora of the Great Basin Flora of the Sonoran Deserts Plants described in 1836 Taxa named by Asa Gray Taxa named by Augustin Pyramus de Candolle Plants used in traditional Native American medicine Flora without expected TNC conservation status