Centromadia pungens, the common spikeweed or common tarweed, is a species of North American 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.Biota of North America Program 2014 county distribution mapCalflora taxon report, University of California, Centromadia pungens (Hook. & Arn.) Greene, common tarweed
Centromadia pungens is an herb up to tall. It produces arrays of numerous yellow flower heads with both ray florets and disc florets.Flora of North America, Spikeweed, Centromadia GreeneGreene, Edward Lee 1894. Manual of the Botany of the Region of San Francisco Bay 196Torrey, John & Gray, Asa 1843. Flora of North America 2(3): 399
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)