Helenium amarum

Taxobox
color = lightgreen
name = "Helenium amarum"

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image_width = 270px
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Asterales
familia = Asteraceae
tribus = Helenieae
genus = "Helenium"
species = "H. amarum"
binomial = "Helenium amarum"
binomial_authority = (Raf.) H.Rock

"Helenium amarum" is a species of annual herb in the daisy family known by the common names yellowdicks, yellow sneezeweed, and bitter sneezeweed. It is native to much of the southeastern United States and northern Mexico, and it is present elsewhere in North America as an introduced species. This is a multibranched bushy erect plant reaching 20 to 70 centimeters in height and thickly foliated in narrow to threadlike leaves. The tops of stem branches hold inflorescences of many daisylike flower heads. Each head has a rounded center of golden yellow disc florets and a fringe of 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 [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.] and insects [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.] due to the presence of the lactone tenulin.

External links

* [http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?609,1294,1295 Jepson Manual Treatment]
* [http://plants.usda.gov/java/profile?symbol=HEAM USDA Plants Profile]
* [http://calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&where-taxon=Helenium+amarum Photo gallery]

References