Ragweed
Ragweed | |
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Ambrosia psilostachya | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Asterales |
Family: | Asteraceae |
Subfamily: | Asteroideae |
Tribe: | Heliantheae |
Subtribe: | Ambrosiinae |
Genus: | Ambrosia L. |
Synonyms[1] | |
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Ragweeds are flowering plants in the genus Ambrosia in the aster
The name "ragweed" is derived from "ragged" + "weed," coming from the ragged appearance of the plant's leaves.[5] Other common names include bursages[6] and burrobrushes.[7] The genus name is from the Greek ambrosia, meaning "food or drink of immortality".[2]
Ragweed pollen is notorious for causing allergic reactions in humans, specifically allergic rhinitis. Up to half of all cases of pollen-related allergic rhinitis in North America are caused by ragweeds.[8]
The most widespread species of the genus in North America is Ambrosia artemisiifolia.
Description and ecology
Ragweeds are
Ragweeds are monoecious, most producing inflorescences that contain both staminate and pistillate flowers. Inflorescences are often in the form of a spike or raceme made up mostly of staminate flowers with some pistillate clusters around the base. Staminate flower heads have stamens surrounded by whitish or purplish florets. Pistillate flower heads have fruit-yielding ovules surrounded by many phyllaries and fewer, smaller florets.[2] The pistillate flowers are wind pollinated,[9][10] and the fruits develop. They are burs, sometimes adorned with knobs, wings, or spines.[2]
Many Ambrosia species occur in desert and semi-desert areas, and many are ruderal species that grow in disturbed habitat types.[3]
Allergy
Ragweed pollen is a common allergen. A single plant may produce about a billion grains of pollen per season,[11][12] and the pollen is transported on the wind. It causes about half of all cases of pollen-associated allergic rhinitis in North America, where ragweeds are most abundant and diverse.[8] Common culprits are common ragweed (A. artemisiifolia) and great ragweed (A. trifida).[13]
Concentration of ragweed pollen—in the absence of significant rainfall, which removes pollen from the air, is the lowest in the early morning hours (6:00 AM), when emissions starts. Pollen concentration peaks at midday.[14] Ragweed pollen can remain airborne for days and travel great distances, and can even be carried 300–400 miles (500–600 km) out to sea.[12] Ragweeds native to the Americas have been introduced to Europe starting in the nineteenth century and especially during World War I, and have spread rapidly since the 1950s.[15] Eastern Europe, particularly Hungary, has been badly affected by ragweed since the early 1990s, when the dismantling of Communist collective agriculture led to large-scale abandonment of agricultural land, and new building projects also resulted in disturbed, un-landscaped areas.[16]
The major allergenic compound in the pollen has been identified as Amb a 1, a 38 k
Ragweed allergy sufferers may show signs of
As of 2006, research into allergy immunotherapy treatment involved administering doses of the allergen to accustom the body to induce specific long-term tolerance.[20]
Control and eradication
Where herbicides cannot be used, mowing may be repeated about every three weeks, as it grows back rapidly. In the past, ragweed was usually cut down, left to dry, and then burned.[21] This method is used less often now, because of the pollution caused by smoke. Manually uprooting ragweed is generally ineffective, and skin contact can cause allergic reaction. If uprooting is the method of choice, it should be performed before flowering. There is evidence that mechanical and chemical control methods are actually no more effective in the long run than leaving the weed in place.[21]
Species
There are about 50 species in genus Ambrosia. Species include:[27]
- Ambrosia acanthicarpa Hook. – flatspine bur ragweed, annual bursage, sand bursage
- Ambrosia acuminata (Brandegee) W.W.Payne
- Ambrosia ambrosioides (Cav.) W.W.Payne – ambrosia-leaf bur ragweed, big bursage, ambrosia bursage
- Ambrosia arborescens Mill. – marko, altamisa
- Ambrosia artemisiifolia L. – common ragweed, short ragweed, Roman wormwood
- Ambrosia artemisioides Meyen & Walp.
- Ambrosia bidentata Michx. – lanceleaf ragweed, southern ragweed
- Ambrosia bryantii (Curran) Payne
- Ambrosia camphorata (Greene) W.W.Payne
- Ambrosia canescens A.Gray – hairy ragweed
- Ambrosia carduacea (Greene) W.W.Payne
- Ambrosia chamissonis (Less.) Greene – silver burr ragweed, beach-bur
- Ambrosia cheiranthifolia A.Gray – Rio Grande ragweed, South Texas ambrosia
- Ambrosia chenopodiifolia (Benth.) W.W.Payne – San Diego bur ragweed, San Diego bursage
- Ambrosia confertiflora DC. – weakleaf bur ragweed
- Ambrosia cordifolia (A.Gray) W.W.Payne – Tucson bur ragweed, heartleaf bursage
- Ambrosia deltoidea (Torr.) W.W.Payne – triangle bur ragweed, triangle bursage
- Ambrosia dentata (Cabrera) M.O.Dillon
- Ambrosia divaricata (Brandegee) Payne
- Ambrosia diversifolia (Piper) Rydb.
- Ambrosia dumosa (A.Gray) W.W.Payne – burrobush, white bursage
- Ambrosia eriocentra (A.Gray) W.W.Payne – woolly fruit bur ragweed, hollyleaf bursage
- Ambrosia flexuosa (A.Gray) W.W.Payne
- Ambrosia grayi (A.Nelson) Shinners – woollyleaf bur ragweed, lagoonweed
- Ambrosia × helenae Rouleau – Helen ragweed
- Ambrosia hispidaPursh – coastal ragweed
- Ambrosia humi León de la Luz & Rebman[3]
- Ambrosia ilicifolia (A.Gray) W.W.Payne – hollyleaf bur ragweed
- Ambrosia × intergradiens W.H.Wagner – intergrading ragweed
- Ambrosia johnstoniorum Henrickson
- Ambrosia linearis (Rydb.) W.W.Payne – streaked bur ragweed
- Ambrosia magdalenae (Brandegee) W.W.Payne
- Ambrosia maritima L.
- Ambrosia microcephala DC.
- Ambrosia monogyra (Torr. & A.Gray) Strother & B.G.Baldwin – singlewhorl burrobrush
- Ambrosia nivea (B.L.Rob. & Fernald) W.W.Payne
- Ambrosia pannosa W.W.Payne
- Ambrosia peruviana Willd. – ragweed, altamisa
- Ambrosia × platyspina (Seaman) Strother & B.G.Baldwin
- Ambrosia polystachya DC.
- Ambrosia psilostachya DC. – Cuman ragweed, western ragweed, perennial ragweed
- Ambrosia pumila (Nutt.) A.Gray – dwarf bur ragweed, San Diego ambrosia
- Ambrosia salsola (Torr. & A. Gray) Strother & B.G. Baldwin
- Ambrosia scabra Hook. & Arn.
- Ambrosia tacorensis Meyen
- Ambrosia tarapacana Phil.
- Ambrosia tenuifolia Spreng. – slimleaf bur ragweed, lacy ambrosia
- Ambrosia tomentosa Nutt. – skeletonleaf bur ragweed
- Ambrosia trifida L. – great ragweed, giant ragweed
- Ambrosia velutina O.E.Schulz
- Ambrosia villosissima Forssk.
References
- ^ "Global Compositae Checklist". Archived from the original on 9 March 2015. Retrieved 6 March 2015.
- ^ a b c d e f Ambrosia. Flora of North America.
- ^ a b c León de la Luz, José Luis; Rebman, Jon P. (June 2010). "A new Ambrosia (Asteraceae) from the Baja California Peninsula, Mexico". Boletín de la Sociedad Botánica de México. 86 (6): 65–70.
- PMID 28321366.
- ^ "ragweed | Etymology, origin and meaning of ragweed by etymonline". www.etymonline.com. Retrieved 2023-07-15.
- ^ Ambrosia. Integrated Taxonomic Information System (ITIS).
- ^ Ambrosia. The Jepson eFlora 2013.
- ^ S2CID 24445801.
- ^ Genus Ambrosia. Arizona-Sonora Desert Museum.
- JSTOR 2439774.
- ISBN 0-316-76985-1"It is estimated that a single plant produces 1 billion shafts of pollen, or that 1 square mile of ragweed plants produces 16 tons of pollen".
- ^ ISBN 1-57356-068-5"Each ragweed plant produces about one billion pollen grains during an average allergy season".
- S2CID 81763493.
- PMID 11258685.
- ISBN 1-84593-265-X
- ^ Kiss pp. 81–82
- S2CID 34313189.
- S2CID 7126007.
- ISBN 978-14292-1919-8.
- S2CID 36043612.
- ^ JSTOR 2484099.
- ^ Kiss, pp. 83–89.
- ^ "Catalogue of Life - 2011 Annual Checklist :: Species details". www.catalogueoflife.org.
- .
- ^ Shiyake, S.; Moriya, S. (2005). "Expansion of Ophraella communa LeSage in east Asia". Insect Nat. 40: 11–13.
- ^ W. A. Palmer and R. D. Goeden The Host Range of Ophraella communa Lesage (Coleoptera: Chrysomelidae)
- ^ Ambrosia. The Plant List.
External links
- Media related to Ambrosia at Wikimedia Commons
- GRIN Species Records of Ambrosia Archived 2008-10-05 at the Wayback Machine. Germplasm Resources Information Network (GRIN).