''Hemizonia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of plants in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Asteraceae 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 ...

. 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 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 ...

, especially

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 ...

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 temperate climate ''Cs'') is a temperate climate sub-type, generally characterized by warm, dry summers and mild, fairly wet winters; these weather conditions are typically experienced in the ...

of California.

Selected species

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

Hemizonia congesta ''Hemizonia congesta'', known by the common name hayfield tarweed, is a species of flowering plant in the family Asteraceae, native to western North America. Description ''Hemizonia congesta'' is a spindly, thin-stemmed annual herb growing ere ...

'' — hayfield tarweed;

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

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. P ...

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

Otay Mesa Otay Mesa ( ) is a community in the southern section of the city of San Diego, 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 of Oc ...

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

Santa Monica Mountains The Santa Monica Mountains is a coastal mountain range in Southern California, next to the Pacific Ocean. It is part of the Transverse Ranges. Because of its proximity to densely populated regions, it is one of the most visited natural areas in ...

. * '' 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 dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

tarweed; coastal California and &

Channel Islands The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...

* '' 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 and western Los Angeles County, of southern California, United States. Geography The Simi Hills are aligned east-west and run for , and average arou ...

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 Cla ...

, and

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...

. 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 ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily in ...

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 B ...

, 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 Coast Ranges, which ...

* '' 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 sp ...

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