| Ambrosia dumosa | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Tribe: | Heliantheae |
| Genus: | Ambrosia |
| Species: | A. dumosa |
| Binomial name | |
| Ambrosia dumosa | |
| Synonyms[1][2] | |
| |
Ambrosia dumosa, theburro-weed orwhite bursage, aNorth American species of plants in the familyAsteraceae. It is a common constituent of thecreosote-bush scrub community throughout theMojave Desert ofCalifornia,Nevada, andUtah and theSonoran Desert ofArizona and northwesternMexico (Baja California,Baja California Sur,Sonora,Chihuahua).[3][4][5][6]
Ambrosia dumosa has been studied to determineallelopathic interactions with creosote bush,Larrea tridentata, which produces a chemical that inhibits the growth ofA. dumosa.[citation needed] Other studies have suggested thatA. dumosa roots produce a chemical that causes them to grow away from conspecific roots, preventing competition for water resources. In addition to burro-weed,A. dumosa is also commonly called white bursage, and burrobush.
Ambrosia dumosa or white bursage is a form of ragweed, is a highly branched shrub 20 to 90 cm in height. The younger stems are covered with soft gray-white hairs. Approximatelyobovate leaves are 1 to 3 timespinnatelycompound or deeplylobed and generally clustered on short branches. The leaves are 0.5 to 4 cm long and also covered in soft gray-white hairs.[3]
Its inflorescence is yellow withstaminate andpistillateheadson a single plant (monoecious).Staminateheads have many flowers and are 3 to 5 mm in diameter with a 5 to 8 lobedinvolucre.Pistillateheads are 2 flowered and lackcorollas.[3]
Ambrosia dumosa has spherical bur-like fruits ranging in color from golden to purple to brown. Along with microscopic hairs, the fruit has 12 to 35 flat and straight spines which are 5 to 9 mm in length and scattered over the surface.[7][3]
Ambrosia dumosa becomes dormant during drought, losing all of its leaves to prevent water loss by transpiration;drought deciduous. During this time, it can still be recognized by the presence of longitudinal stripes on smaller stems.[7]
Like other types of Ambrosia, this is a ragweed, wind-blown pollen from burro-weed can cause serious allergic reactions. Increasing cases in Mojave Desert as the population grows from Joshua Tree, CA to Las Vegas, NV.
