''Hemizonia'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of plants in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

. They are known generally as tarweeds, although some tarweeds belong to other genera, such as ''

Madia ''Madia'' is a genus of annual or perennial usually aromatic herbs with yellow flowers, in the tribe Madieae within the family Asteraceae.

'' and ''

Deinandra ''Deinandra'' is a genus of flowering plants in the tribe Madieae within the family Asteraceae. Such a genus is not recognized as distinct by all authorities; its species are often treated as members of the genus '' Hemizonia''. Distribution ''D ...

''. Furthermore, ''Hemizonia'' is currently being revised; some species may be segregated into new genera.

Range

The ''Hemizonia'' tarweeds are native to southwestern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, especially

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Description

''Hemizonia'' are usually sticky, aromatic, yellow-flowered annual plants which are hardy and competitive, especially in the dry

Mediterranean climate A Mediterranean climate ( ), also called a dry summer climate, described by Köppen and Trewartha as ''Cs'', is a temperate climate type that occurs in the lower mid-latitudes (normally 30 to 44 north and south latitude). Such climates typic ...

of California.

Selected species

* '' Hemizonia arida'' — Red Rock tarweed * '' Hemizonia clementina'' — Catalina tarweed; Santa Catalina Island, Channel Islands * '' Hemizonia congesta'' — hayfield tarweed;

Central Valley (California) The Central Valley is a broad, elongated, flat valley that dominates the interior of California, United States. It is wide and runs approximately from north-northwest to south-southeast, inland from and parallel to the Pacific coast. It cover ...

California Coast Ranges The Coast Ranges of California span from Del Norte County, California, Del Norte or Humboldt County, California, south to Santa Barbara County, California, Santa Barbara County. The other three coastal California mountain ranges are the Trans ...

, SW Oregon * ''Hemizonia conjugens— Deinandra conjugens'' — Otay tarweed;

Otay Mesa Otay Mesa ( ) is a community in the southern exclave of San Diego, California, just north of the U.S.–Mexico border. It is bordered by the Otay River Valley and the city of Chula Vista on the north; Interstate 805 and the neighborhoods o ...

area, San Diego. * ''Hemizonia fasciculata— Deinandra fasciculata'' — clustered tarweed;

Santa Monica Mountains The Santa Monica Mountains are a coastal mountain range in Southern California, next to the Pacific Ocean. It is part of the Transverse Ranges. The Santa Monica Mountains National Recreation Area encompasses this mountain range. Because of its p ...

. * '' Hemizonia fitchii'' — Fitch's tarweed * '' Hemizonia floribunda'' — Tecate tarweed * '' Hemizonia frutescens'' * '' Hemizonia greeneana'' * ''Hemizonia increscens— Deinandra increscens'' —

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

tarweed; coastal California and &

Channel Islands The Channel Islands are an archipelago in the English Channel, off the French coast of Normandy. They are divided into two Crown Dependencies: the Jersey, Bailiwick of Jersey, which is the largest of the islands; and the Bailiwick of Guernsey, ...

* '' Hemizonia kelloggii'' — Kellogg's tarweed * '' Hemizonia lobbii'' — threeray tarweed * ''Hemizonia minthornii— Deinandra minthornii'' — Santa Susana tarweed;

Simi Hills The Simi Hills are a low rocky mountain range of the Transverse Ranges in eastern Ventura County, California, Ventura County and western Los Angeles County, California, Los Angeles County, of Southern California, United States. The range runs ma ...

Santa Susana Mountains The Santa Susana Mountains are a transverse range of mountains in Southern California, north of the city of Los Angeles, in the United States. The range runs east-west, separating the San Fernando and Simi valleys on its south from the Santa ...

, and

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

. State and CNPS listed

vulnerable species A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...

. * ''Hemizonia mohavensis— Deinandra mohavensis'' — Mojave tarweed; west

Mojave Desert The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...

Transverse Ranges The Transverse Ranges are a group of mountain ranges of Southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Ba ...

, northern

Peninsular Ranges The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from Southern California to the southern tip of the Baja California peninsula; they are part of the North American Pacific Coast Range ...

* '' Hemizonia palmeri'' * '' Hemizonia paniculata'' — San Diego tarweed * '' Hemizonia pungens'' — common tarweed Encyclopedia of Life: Information on Common Tarweed (''Hemizonia pungens'')
. accessed 6.24.2012 * ''

Hemizonia streetsii ''Hemizonia'' is a genus of plants in the family Asteraceae. They are known generally as tarweeds, although some tarweeds belong to other genera, such as ''Madia'' and ''Deinandra''. Furthermore, ''Hemizonia'' is currently being revised; some spe ...

References

External links

USDA Plants Profile: ''Hemizonia'' (Tarweeds)Jepson Manual Treatment: ''Hemizonia''Encyclopedia of Life: Information on the Tarweeds (''Hemizonia'' species)
* Madieae Flora of California Flora of Baja California Flora of Northwestern Mexico Flora of the Northwestern United States Flora of the Southwestern United States Taxa named by Augustin Pyramus de Candolle Asteraceae genera {{Madieae-stub