Helenium amarum

Helenium amarum
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Helenieae
Genus: Helenium
Species: H. amarum
Binomial name
Helenium amarum
(Raf.) H.Rock
Synonyms[1][2]
  • 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, New Mexico)[3] and northern Mexico (Chihuahua, Coahuila),[4] and it is present elsewhere in North America, Australia, and the West Indies as an introduced species.[3][5][6][7]

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.[4]

The plant is somewhat toxic to mammals[8] and insects[9] due to the presence of the lactone tenulin.

Varieties[1][4]

References

  1. 1 2 The Plant List, Helenium amarum (Raf.) H.Rock
  2. ↑ Tropicos, Gaillardia amara Raf.
  3. 1 2 Biota of North America Program 2014 county distribution map
  4. 1 2 3 Flora of North America, Helenium amarum (Rafinesque) H. Rock, 1957. Yellowdicks, fiveleaf sneezeweed
  5. ↑ Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100.
  6. ↑ Tropicos, specimen listing for Helenium amarum (Raf.) H. Rock
  7. ↑ Queensland Government, Department of Agriculture and Fisheries, Bitter weed (Helenium amarum)
  8. ↑ 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.
  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.
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