''Ambrosia psilostachya'' is a species of ragweed known by the common names Cuman ragweed and perennial ragweed, and western ragweed.

Distribution and habitat

The plant is widespread across much of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

( United States, Canada, and northern Mexico). It is also naturalized in parts of Europe, Asia,

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, and South America. It is a common plant in many habitat types, including disturbed areas such as roadsides.Flora of North America Vol. 21 Page 18 ''Ambrosia psilostachya'' de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
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Description

''Ambrosia psilostachya'' is an erect perennial herb growing a slender, branching, straw-colored stem to a maximum height near two meters, but more often remaining under one meter tall. Leaves are up to 12 centimeters long and vary in shape from lance-shaped to nearly oval, and they are divided into many narrow, pointed lobes. The stem and leaves are hairy. The top of the stem is occupied by an inflorescence which is usually a spike. The species is

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

, and the inflorescence is composed of staminate (male) flower heads with the pistillate heads located below and in the axils of leaves. This bloom period is from June through November. The pistillate heads yield fruits which are

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

s located within oval-shaped greenish-brown burs about half a centimeter long. The burs are hairy and sometimes spiny. The plant reproduces by seed and by sprouting up from a creeping rhizome-like root system.

Ecology

''Ambrosia psilostachya'' is a host plant for the caterpillars of '' Bucculatrix transversata'', ''

Cosmopterix opulenta ''Cosmopterix opulenta'' is a moth of the family Cosmopterigidae. It is known from the United States (California, Oklahoma, Arizona, New Mexico) and Costa Rica. Description Male, female. Forewing length 3.3-3.6 mm. Head: frons shining ochr ...

'', ''

Exaeretia gracilis ''Exaeretia gracilis'' is a moth in the family Depressariidae. It was described by Lord Walsingham in 1889. It is found in North America, where it has been recorded from North Dakota to Texas and in California, Colorado, Minnesota, Oklahoma, Wis ...

'', ''

Gnorimoschema saphirinella ''Gnorimoschema saphirinella'' is a moth in the family Gelechiidae. It was described by Vactor Tousey Chambers in 1875. It is widespread throughout North America, where it has been recorded from Alabama, Arizona, California, Colorado, Flori ...

'', '' Schinia sexplagiata''; the beetles ''

Zygogramma disrupta ''Zygogramma disrupta'' is a species of beetle belonging to the family Chrysomelidae. Description ''Z. disrupta'' is a small leaf beetle with a brown pronotum and yellow elytra marked with elongated brown stripes. Distribution and Habitat ''Z. d ...

'', ''

Zygogramma suturalis ''Zygogramma suturalis'', commonly known as the ragweed leaf beetle, is a species of leaf beetle belonging to the genus ''Zygogramma''. Native to North America, it has been introduced into Russia and China for the biological pest control of ragw ...

''; and the grasshopper ''

Spharagemon collare ''Spharagemon collare'', the mottled sand grasshopper, is found in sandy-soiled, grassy areas of northern United States and southern Canada. They are known to be a minor pest of wheat crops; however, populations are rarely large enough to cause ...

''.

Medicinal uses

This plant had a number of medicinal uses among several different Native American tribes, including the Cheyenne, Kumeyaay (Diegueno), and

Kiowa people Kiowa () people are a Native American tribe and an indigenous people of the Great Plains of the United States. They migrated southward from western Montana into the Rocky Mountains in Colorado in the 17th and 18th centuries,Pritzker 326 and eve ...

Chemistry

''Ambrosia psilostachya'' contains a group of

phytochemical Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poisons ...

s called

psilostachyin Psilostachyins are group of chemical compounds isolated from '' Ambrosia psilostachya''. References Ambrosia (plant) Lactones {{organic-compound-stub ...

References

External links

Calflora Database: ''Ambrosia psilostachya'' (Western ragweed)Jepson Manual eFlora (TJM2) treatment: ''Ambrosia psilostachya''
* ttps://web.archive.org/web/20080916225004/http://www.npwrc.usgs.gov/resource/plants/wildflwr/species/ambrpsil.htm USGS.gov: Northern Prairie Wildlife Profilebr>UC Calphotos Photos gallery of ''Ambrosia psilostachya''
{{Taxonbar, from=Q3613854 psilostachya Flora of Canada Flora of Northeastern Mexico Flora of Northwestern Mexico Flora of the Eastern United States Flora of the Western United States Plants described in 1836 Taxa named by Augustin Pyramus de Candolle Natural history of the California chaparral and woodlands Plants used in traditional Native American medicine Flora without expected TNC conservation status