''Centromadia pungens'', the common spikeweed or common tarweed, is a species of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

n plants in the tribe Madieae within the family Asteraceae. It is native to northern Baja California and the western United States ( California, Oregon, Washington, Idaho, Nevada, Arizona). The plant is considered a noxious weed in parts of the Pacific Northwest. ''Centromadia pungens'' is an herb up to tall. It produces arrays of numerous yellow

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 ...

with both ray florets and disc florets.Torrey, John & Gray, Asa 1843. Flora of North America 2(3): 399
/ref> ;Subspecies * ''Centromadia pungens'' subsp. ''laevis'' (D.D.Keck) B.G.Baldwin - Baja California, southern California * ''Centromadia pungens'' subsp. ''pungens'' - most of species range

References

External links

Calflora Database: ''Centromadia pungens'' (Common spikeweed, Common tarweed) Jepson eFlora (TJM2): ''Centromadia pungens'' USDA Plants Profile for ''Centromadia pungens'' (common tarweed)
* Madieae Flora of the Northwestern United States Flora of the Southwestern United States Flora of Baja California Flora of California Plants described in 1839 Taxa named by William Jackson Hooker Taxa named by Edward Lee Greene Flora without expected TNC conservation status {{Asteroideae-stub