Helenium amarum

Helenium amarum
Conservation status
	; Secure (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Helenium
Species:	H. amarum
Binomial name
	Helenium amarum; (Raf.) H.Rock
Synonyms
	Gaillardia amara Raf.; Galardia amara Raf.; Helenium badium (A.Gray ex S.Watson) Greene;

Helenium amarum is a species of annual herb in the daisy family known by the common names yellowdicks, yellow sneezeweed, fiveleaf sneezeweed, and bitter sneezeweed. It is native to much of the south-central United States (Texas, Oklahoma, Louisiana, Arkansas, New Mexico)^[4] and northern Mexico (Chihuahua, Coahuila),^[5] and it is present elsewhere in North America, Australia, and the West Indies as an introduced species.^[4]^[6]^[7]^[8]

Helenium amarum is a multibranched bushy erect plant reaching 20 to 70 centimeters (8-28 inches) in height and thickly foliated in narrow to threadlike leaves. The tops of stem branches hold

ray florets which are reflexed away from the center. The fruit is a tiny achene about a millimeter long. This herb is weedy in some areas.^[5]

The plant is somewhat toxic to mammals [9] and insects^[10] due to the presence of the lactone tenulin.

Varieties^[2]^[5]

Helenium amarum var. amarum - United States
Helenium amarum var. badium Waterf. - Oklahoma, Texas, Chihuahua, Coahuila

References

^ "NatureServe Explorer 2.0". explorer.natureserve.org.
^ ^a ^b "Helenium amarum". The Plant List. Royal Botanic Gardens, Kew. Note that this website has been superseded by World Flora Online
^ "Gaillardia amara". Tropicos. Missouri Botanical Garden.
^ ^a ^b "Helenium amarum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
^ ^a ^b ^c Bierner, Mark W. (2006). "Helenium amarum". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 21. New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
^ Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100.
^ Tropicos, specimen listing for Helenium amarum (Raf.) H. Rock
^ Queensland Government, Department of Agriculture and Fisheries, Bitter weed (Helenium amarum)
^ Ivie, G. W., et al. (1975). Toxicity and milk bittering properties of tenulin, the major sesquiterpene lactone constituent of Helenium amarum (bitter sneezeweed). J Agric Food Chem 23:5 845-9.
^ Arnason, J. T., et al. (1987). Mode of action of the sesquiterpene lactone, tenulin, from Helenium amarum against herbivorous insects. J Nat Prod 50:4 690-5.

External links

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[natureserve-1] "NatureServe Explorer 2.0". explorer.natureserve.org.

[wwww-2] "Helenium amarum". The Plant List. Royal Botanic Gardens, Kew. Note that this website has been superseded by World Flora Online

[3] "Gaillardia amara". Tropicos. Missouri Botanical Garden.

[wwwwwww-4] "Helenium amarum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.

[wwwwww-5] Bierner, Mark W. (2006). "Helenium amarum". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 21. New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.

[6] Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100.

[7] Tropicos, specimen listing for Helenium amarum (Raf.) H. Rock

[8] Queensland Government, Department of Agriculture and Fisheries, Bitter weed (Helenium amarum)

[9] Ivie, G. W., et al. (1975). Toxicity and milk bittering properties of tenulin, the major sesquiterpene lactone constituent of Helenium amarum (bitter sneezeweed). J Agric Food Chem 23:5 845-9.

[10] Arnason, J. T., et al. (1987). Mode of action of the sesquiterpene lactone, tenulin, from Helenium amarum against herbivorous insects. J Nat Prod 50:4 690-5.

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