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Yellowdicks

Helenium amarum (Rafin.) H. Rock

Comprehensive Description

provided by North American Flora
Helenium tenuifolium Nutt. Jour. Acad. Phila. 7: 66. 1834
Heleniastrum tenuifolium Kuntze, Rev. Gen. 342. 1891.
A leafy annual; stem fastigiately branched above, 2-4 dm. high, glabrous or with a fewscattered hairs above; leaves glabrous, linear-filiform, entire, 1-5 cm. long, 1-2 mm. wide, not decurrent; heads corymbose; peduncles slender, 5-7 cm. long; involucre about 1 cm. broad; bracts glabrous, thin, long-attenuate from a lanceolate base; receptacle depressedhemispheric; ray-flowers 5-10, pistillate; ligules cuneate, 5-10 mm. long, 3-5 mm. wide, deeply 3-lobed; disk globose, about 8 mm. broad; corollas 2.5 mm. long; tube a minute ring; throat deeply campanulate; lobes 5, ovate; achenes about 1 mm. long, hispid on the short angles; squamellae ovate, as long as the achenes, the midrib excurrent into an awn nearly as long.
Type locality: Mississippi.
Distribution: Virginia to Kansas, Texas, and Florida; Cuba.
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bibliographic citation
Per Axel Rydberg. 1915. (CARDUALES); CARDUACEAE; HELENIEAE, TAGETEAE. North American flora. vol 34(2). New York Botanical Garden, New York, NY
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Helenium amarum

provided by wikipedia EN

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 inflorescences of many daisy-like flower heads. Each head has a rounded center of sometimes as many as 250 golden yellow disc florets and a fringe of 8-10 usually lighter yellow 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]

References

  1. ^ "NatureServe Explorer 2.0". explorer.natureserve.org.
  2. ^ a b "Helenium amarum". The Plant List. Missouri Botanical Garden. Royal Botanic Gardens, Kew.{{cite web}}: CS1 maint: others (link) Note that this website has been superseded by World Flora Online
  3. ^ "Gaillardia amara". Tropicos. Missouri Botanical Garden.
  4. ^ a b "Helenium amarum". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
  5. ^ 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 – 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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Helenium amarum: Brief Summary

provided by wikipedia EN

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) and northern Mexico (Chihuahua, Coahuila), and it is present elsewhere in North America, Australia, and the West Indies as an introduced species.

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 inflorescences of many daisy-like flower heads. Each head has a rounded center of sometimes as many as 250 golden yellow disc florets and a fringe of 8-10 usually lighter yellow 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.

The plant is somewhat toxic to mammals and insects due to the presence of the lactone tenulin.

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