''Holocarpha obconica'', commonly known as the San Joaquin tarweed, is a North American plant species in the sunflower family. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to (found only in)

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, primarily in the Central Valley and adjacent regions.CalFlora taxon report, University of California, ''Holocarpha obconica'' (J. Clausen & Keck) Keck, San Joaquin tarweed
. accessed 11.14.2011. The

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

''"obconica"'' means " obconical," in other words, shaped like a cone but with the widest part farthest from the base. Achenes of ''H. obconica'' are obconical. The plant is a

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...

-containing herb up to 120 cm (4 feet) tall. It produces numerous flower heads, each head containing 4–9 yellow ray flowers surrounding 11–21 small yellow disc flowers, the disc flowers having yellow or brown anthers.Clausen, Jens Christian & Keck, David Daniels. 1935. Madroño 3(1): 7, ''Hemizonia obconica''

References

External links

photo of herbarium specimen at Missouri Botanical Garden, collected in Alameda County in 1933, isotype of ''Holocarpha obconica''Calphotos photo gallery, University of California
{{Taxonbar, from=Q15583498 Madieae Endemic flora of California Plants described in 1935