''Simsia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

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 d ...

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 ...

.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 ...

perennials A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

, and shrubs. 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 a ...

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 souther ...

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, t ...

, 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 op ...

). There are, however, several species in which the cypsela is

biconvex Biconvex may refer to: * Biconvex bipartite graph * Biconvex lens * Biconvex optimization Biconvex optimization is a generalization of convex optimization Convex optimization is a subfield of mathematical optimization that studies the problem ...

, 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 ob ...

'', 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 Sunflower seed, edible oily seeds. Apart from sunflower oil, cooking oil production, it is also used as livestock forage (as ...

''), 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 ''Simsia amplexicaulis'' is a species of flowering plant in 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. C ...

'' (Cav.) Pers. - Guatemala, Honduras, 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 and 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 32 federal entities of Mexico. It comprises 124 municipalities ...

) * ''

Simsia annectens ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' 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 ) , population_note = , population_rank = 10th , timezone1 = CST , utc_offset1 = −6 , timezone1_DST = CDT , utc_offset1_DST = −5 , postal_code_type = Postal ...

Guerrero Guerrero is one of the 32 states that comprise the Administrative divisions of Mexico, 32 Federal Entities of Mexico. It is divided in Municipalities of Guerrero, 81 municipalities and its capital city is Chilpancingo and its largest city is Acap ...

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 ...

Nayarit Nayarit (), officially the Free and Sovereign State of Nayarit ( es, Estado Libre y Soberano de Nayarit), is one of the 31 states that, along with Mexico City, comprise the Federal Entities of Mexico. It is divided in 20 municipalities and its ...

* '' 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 ...

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 Hidalgo may refer to: People * Hidalgo (nobility), members of the Spanish nobility * Hidalgo (surname) Places Mexico * Hidalgo (state), in central Mexico * Hidalgo, Coahuila, a town in the north Mexican state of Coahuila * Hidalgo, Nuevo Le� ...

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 * ''

Simsia chaseae ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' (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 The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...

* '' 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 ...

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

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,

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 Sovereign state, country in Central America, bordered by Honduras to the north, the Caribbean Sea, Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to ...

* ''

Simsia fruticulosa ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' (Sprengel) S.F.Blake - Colombia,

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

, Guatemala * ''

Simsia grandiflora ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' Benth. ex Oerst. -

, Honduras,

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 by ...

, Guatemala,

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

, Guatemala * '' Simsia hispida'' (Kunth) Cass. - San Luis Potosí,

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

* ''

Simsia jamaicensis ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' 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 Hispan ...

* ''

Simsia lagasceiformis ''Simsia lagasceiformis'', the annual bush sunflower, is a species of flowering plant in the family Asteraceae. It is native to seasonally dry tropical areas of Arizona, New Mexico, Texas, Mexico, and Guatemala, and it has been introduced to Mary ...

'' DC. – Annual bush sunflower - Mexico, Guatemala, United States ( AZ TX NM) * '' Simsia molinae'' H.Rob. & Brettell - Honduras,

* '' Simsia pastoensis'' Triana - Colombia * ''

Simsia sanguinea ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' A.Gray -

, Guatemala,

Oaxaca ) , population_note = , population_rank = 10th , timezone1 = CST , utc_offset1 = −6 , timezone1_DST = CDT , utc_offset1_DST = −5 , postal_code_type = Postal ...

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 Cu ...

* '' Simsia santarosensis'' Spooner - Costa Rica * ''

Simsia setosa ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' 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 Federal Entities of Mexico. The state is divided into 72 municipalities; the ...

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 i ...

* ''

Simsia steyermarkii ''Simsia'' is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argen ...

'' H.Rob. & Brettell - Guatemala * '' Simsia subaristata'' A.Gray -

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

* '' Simsia villasenorii'' Spooner -

Oaxaca ) , population_note = , population_rank = 10th , timezone1 = CST , utc_offset1 = −6 , timezone1_DST = CDT , utc_offset1_DST = −5 , postal_code_type = Postal ...

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

Geraea ''Geraea'' is a genus of the family Asteraceae from the southwestern United States and northwestern Mexico, commonly called the desert sunflower. ; Species * ''Geraea canescens'' Torr. & A.Gray - California, Arizona, Nevada, Utah * ''Geraea vis ...

Iostephane ''Iostephane'' is a genus of Mexican flowering plants in the family Asteraceae. They were first published in G.Bentham & J.D.Hooker, Genera Plantarum Vol.2 on page 368 in 1873. The species are rosette-forming herbaceous perennials that produce ...

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