''Helenium amarum'' is a species of annual herb in the

daisy family The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

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 Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

Oklahoma Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

) and northern Mexico (

Chihuahua Chihuahua may refer to: Places *Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state **Chihuahua Mun ...

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

), and it is present elsewhere in North America, Australia, and the West Indies as an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

. ''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

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s of many daisy-like

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

. 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 An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

about a millimeter long. This herb is weedy in some areas. The plant is somewhat toxic to mammals and insectsArnason, 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. ; Varieties * ''Helenium amarum'' var. ''amarum'' - United States * ''Helenium amarum'' var. ''badium'' Waterf. -

References

External links

Jepson Manual Treatment

United States Department of Agriculture Plants Profile

Calphotos Photo gallery, University of California

Photo of herbaruim specimen at Missouri Botanical Garden, collected in Mississippi in 2007

*
Discover Life
Plants described in 1817 Flora of North America

amarum In the mythology of the Quechua people of Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (embl ...

{{Helenieae-stub