https://www.gardenology.org/w/index.php?action=history&feed=atom&title=Ambrosia_dumosaAmbrosia dumosa - Revision history2026-04-10T09:06:04ZRevision history for this page on the wikiMediaWiki 1.43.0https://www.gardenology.org/w/index.php?title=Ambrosia_dumosa&diff=6468&oldid=prevMediaWiki default at 13:40, 5 August 20072007-08-05T13:40:21Z<p></p>
<p><b>New page</b></p><div>{{Taxobox<br />
| color = lightgreen<br />
| name = ''Ambrosia dumosa''<br />
| image = Ambrosia_dumosa_2.jpg<br />
| image_width = 240px<br />
| regnum = [[Plant]]ae<br />
| divisio = [[Magnoliophyta]]<br />
| classis = [[Magnoliopsida]]<br />
| ordo = [[Asterales]]<br />
| familia = [[Asteraceae]]<br />
| genus = ''[[ragweed|Ambrosia]]''<br />
| species = '''''A. dumosa'''''<br />
| binomial = ''Ambrosia dumosa''<br />
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| binomial_authority = ([[Asa Gray|A.Gray]]) [[Willard William Payne|W.W.Payne]]<br />
}}<br />
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'''''Ambrosia dumosa''''', the '''burro-weed''' or '''white bursage''', is a common constituent of the creosote-bush scrub community throughout the Mojave desert of California, Nevada, and Utah and the Sonoran Desert of Arizona and northwestern Mexico. ''Ambrosia dumosa'' has been studied to determine [[allelopathy|allelopathic]] interactions with creosote bush, ''[[Larrea tridentata]]'', which produces a chemical that inhibits the growth of ''A. dumosa''. Other studies have suggested that ''A. dumosa'' roots produce a chemical that causes them to grow away from conspecific roots, preventing competition for water resources. In addition to burrow-weed, ''A. dumosa'' is also commonly called bur sage, burro weed, and burro bush.<br />
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===Morphology===<br />
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''A. dumosa'' is a highly branched shrub 20 to 90 cm in height. The younger stems are covered with soft gray-white hairs. Approximately obvate leaves are 1 to 3 times pinnately compound or deeply lobed and generally clustered on short branches. The leaves are 0.5 to 4 cm long and also covered in soft gray-white hairs.<br />
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Its inflorescence is yellow with staminate and pistallate heads on a single plant ([[monoecious]]). Staminate heads have many flowers and are 3 to 5 mm in diameter with a 5 to 8 lobed [[involucre]]. Pistillate heads are 2 flowered and lack corolla.<br />
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''A. 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. <br />
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''A. dumosa'' becomes dormant during drought, losing all of its leaves to prevent water loss by transpiration. During this time it can still be recognized by the presence of longitudinal stripes on smaller stems. <br />
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Like other [[ragweed]]s, wind blown pollen from burro-weed may be highly allergenic.<br />
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== References ==<br />
{{commons|Ambrosia dumosa}}<br />
*[http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?609,648,655 Jepson Manual Treatment: ''Ambrosia dumosa'']<br />
*Schoenerr, Allen A. (1992). ''A Natural History of California''. Berkeley: University of California Press. ISBN 0-520-06922-6<br />
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[[Category:Asteraceae]]<br />
[[Category:Flora of California]]<br />
[[Category:Flora of the Colorado Desert]]<br />
[[Category:Flora of the Mojave Desert]]<br />
[[Category:Flora of the Sonoran Desert]]<br />
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