''Simsia'' 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 ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s in the tribe

Heliantheae The Heliantheae (sometimes called the sunflower tribe) are the third-largest tribe in the sunflower family (Asteraceae). With some 190 genera and nearly 2500 recognized species, only the tribes Senecioneae and Astereae are larger. The name is de ...

within the family

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 ...

.Tropicos, ''Simsia'' Pers.
/ref> It includes annuals,

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

perennials, and

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s. They range from the

western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the Wes ...

south through

Central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

, with the center of diversity occurring in Mexico. The genus is named for British physician and botanist John Sims (1749–1831). Although some species are relatively rare, others have become common weeds that line the roadsides and fields of Mexico, often forming dense stands mixed with ''

Tithonia ''Tithonia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. ''Tithonia'' has a center of distribution in Mexico but with one species extending into the Southwestern United States and several native to Centr ...

'' and other

. Some species are known by the common name bushsunflower.

Description and systematics

A feature that characterizes many of the species of the genus and helps to distinguish them from related genera is the extremely flattened cypsela (

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

). There are, however, several species in which the cypsela is biconvex, and these are recognized as belonging to ''Simsia'' by a group of other, mostly technical features, including nodal disks (stipule-like appendages at the base of the petioles), relatively long and narrow ray ovaries, and long and tapering style branches that lack a pronounced apical appendage. The genus was thoroughly studied by Spooner using comparative morphology, chromosome counts, and crossing experiments, and based on samples from wide-ranging field work. Subsequently two new species have been documented, and additional species are being transferred into the genus. Although at one time, ''Simsia'' was considered to be related to other genera with flattened cypselae, such as ''

Encelia ''Encelia'' is a genus of the plant family Asteraceae. It consists of shrubs (and one geophyte) of arid environments in southwestern North America and western South America. All have n = 18 chromosomes. All the North American species are obliga ...

'', it is now firmly established that ''Simsia'' is part of subtribe Helianthinae (the taxonomic group which includes the common sunflower, ''

Helianthus annuus The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as b ...

''), and is a close relative of ''Tithonia'' All of the species for which chromosome counts have been made are diploid (''x'' = 17), and crossing experiments suggest that there are few barriers to hybridization between species of the genus. Natural hybridization appears to occur and may complicate identification of some specimens, particularly involving the weedy species such as ''S. foetida'', ''S. amplexicaulis'', and ''S. lagascaeformis''. ; SpeciesFlann, C (ed) 2009+ Global Compositae Checklist
Biota of North America Program 2013 county distribution maps
/ref> * '' Simsia amplexicaulis'' (Cav.) Pers. -

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...

, Mexico (from

Chihuahua Chihuahua may refer to: Places *Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state **Chihuahua Mun ...

Chiapas Chiapas (; Tzotzil language, Tzotzil and Tzeltal language, Tzeltal: ''Chyapas'' ), officially the Free and Sovereign State of Chiapas ( es, Estado Libre y Soberano de Chiapas), is one of the states that make up the Political divisions of Mexico, ...

) * '' Simsia annectens'' S.F.Blake -

Michoacán Michoacán, formally Michoacán de Ocampo (; Purépecha: ), officially the Free and Sovereign State of Michoacán de Ocampo ( es, Estado Libre y Soberano de Michoacán de Ocampo), is one of the 32 states which comprise the Federal Entities of ...

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...

, Guerrero,

México State The State of Mexico ( es, Estado de México; ), officially just Mexico ( es, México), is one of the 32 federal entities of the United Mexican States. Commonly known as Edomex (from ) to distinguish it from the name of the whole country, it is ...

Jalisco Jalisco (, , ; Nahuatl: Xalixco), officially the Free and Sovereign State of Jalisco ( es, Estado Libre y Soberano de Jalisco ; Nahuatl: Tlahtohcayotl Xalixco), is one of the 31 states which, along with Mexico City, comprise the 32 Federal En ...

, Nayarit * '' Simsia calva'' (A.Gray) A.Gray – Awnless bush sunflower -

Nuevo León Nuevo León () is a state in the northeast region of Mexico. The state was named after the New Kingdom of León, an administrative territory from the Viceroyalty of New Spain, itself was named after the historic Spanish Kingdom of León. With a ...

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

, Hidalgo,

Tamaulipas Tamaulipas (), officially the Free and Sovereign State of Tamaulipas ( es, Estado Libre y Soberano de Tamaulipas), is a state in the northeast region of Mexico; one of the 31 states which, along with Mexico City, comprise the 32 Federal Entiti ...

, United States ( TX NM) * '' Simsia caucana'' Cuatrec. - Cauca in

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

* '' Simsia chaseae'' (Millspaugh) S.F.Blake -

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

, Yucatán Peninsula * '' Simsia dombeyana'' (A.Gray) S.F.Blake -

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

Paraguay Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...

* '' Simsia eurylepis'' S.F.Blake -

San Luis Potosí San Luis Potosí (), officially the Free and Sovereign State of San Luis Potosí ( es, Estado Libre y Soberano de San Luis Potosí), is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 58 municipalities and i ...

Campeche Campeche (; yua, Kaampech ), officially the Free and Sovereign State of Campeche ( es, Estado Libre y Soberano de Campeche), is one of the 31 states which make up the 32 Federal Entities of Mexico. Located in southeast Mexico, it is bordered by ...

* '' Simsia foetida'' (Cav.) S.F.Blake - from

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the cou ...

* '' Simsia fruticulosa'' (Sprengel) S.F.Blake -

* '' Simsia ghiesbreghtii'' (A.Gray) S.F.Blake -

* '' Simsia grandiflora'' Benth. ex Oerst. -

El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south b ...

* '' Simsia guatemalensis'' H.Rob. & Brettell -

* '' Simsia hispida'' (Kunth) Cass. -

* '' Simsia holwayi'' S.F.Blake -

* '' Simsia jamaicensis'' S.F.Blake -

Jamaica Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of His ...

* '' Simsia lagasceiformis'' DC. – Annual bush sunflower - Mexico,

, United States ( AZ TX NM) * '' Simsia molinae'' H.Rob. & Brettell -

* '' Simsia pastoensis'' Triana -

* '' Simsia sanguinea'' A.Gray -

Puebla Puebla ( en, colony, settlement), officially Free and Sovereign State of Puebla ( es, Estado Libre y Soberano de Puebla), is one of the 32 states which comprise the Federal Entities of Mexico. It is divided into 217 municipalities and its cap ...

Morelos Morelos (), officially the Free and Sovereign State of Morelos ( es, Estado Libre y Soberano de Morelos), is one of the 32 states which comprise the Federal Entities of Mexico. It is divided into 36 municipalities and its capital city is Cuer ...

* '' Simsia santarosensis'' Spooner -

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

* '' Simsia setosa'' S.F.Blake -

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

Durango Durango (), officially named Estado Libre y Soberano de Durango ( en, Free and Sovereign State of Durango; Tepehuán: ''Korian''; Nahuatl: ''Tepēhuahcān''), is one of the 31 states which make up the 32 Federal Entities of Mexico, situated in ...

, Nayarit * '' Simsia steyermarkii'' H.Rob. & Brettell -

* '' Simsia subaristata'' A.Gray -

* '' Simsia tenuis'' (Fernald) S.F.Blake - Guerrero * '' Simsia villasenorii'' Spooner -

; Formerly included numerous species now regarded as members of other genera: ''

Geraea Iostephane

Viguiera ''Viguiera'' is a genus of flowering plants in the family Asteraceae. The name honours French physician L. G. Alexandre Viguier (1790–1867). It contains around 150 species, which are commonly known as goldeneyes and are native to the New World ...

References

* * {{Taxonbar, from=Q4419875 Asteraceae genera Heliantheae