Simsia | |
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Simsia calva | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Asterales |
Family: | Asteraceae |
Subfamily: | Asteroideae |
Tribe: | Heliantheae |
Subtribe: | Helianthinae |
Genus: | Simsia Pers. 1807, [1] not R. Br. 1810 (Proteaceae) [2] |
Type species | |
Simsia amplexicaulis [3] [4] | |
Synonyms [5] | |
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Simsia is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. [3] [6] It includes annuals, herbaceous perennials, and shrubs. They range from the western United States south through Central and South America to Argentina, with the center of diversity occurring in Mexico. The genus is named for British physician and botanist John Sims (1749–1831). [7] 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 and other Asteraceae. Some species are known by the common name bushsunflower. [8]
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). 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. [7]
The genus was thoroughly studied by Spooner [9] using comparative morphology, chromosome counts, and crossing experiments, and based on samples from wide-ranging field work. Subsequently two new species have been documented, [10] 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 , it is now firmly established that Simsia is part of subtribe Helianthinae (the taxonomic group which includes the common sunflower, Helianthus annuus ), and is a close relative of Tithonia [7] [11]
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. [4]
numerous species now regarded as members of other genera: Encelia Geraea Iostephane Viguiera
Melampodium is a genus of flowering plants in the sunflower family.
The Heliantheae 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 derived from the genus Helianthus, which is Greek for sun flower. Most genera and species are found in North America and South America. A few genera are pantropical.
Viguiera is a genus of flowering plants in the family Asteraceae. It contains around 19–40 species, which are commonly known as goldeneyes and are native to the New World. These are herbs to bushy shrubs that bear yellow or orange daisy-like flowers.
Gonolobus is a genus of plant in family Apocynaceae, first described in 1803. It is native to South America, Central America, Mexico, the West Indies, and the southern United States.
Tithonia is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae.
Heliomeris is a genus of flowering plants in the family Asteraceae, known generally as false goldeneyes.
Roldana also known as groundsel is a genus of large herbs or subshrubs from the tribe groundsel tribe within the sunflower family.
Hymenostephium is a genus of flowering plants in the family Asteraceae. It includes herbs and slender shrubs that occur from Mexico through to Venezuela and north-western Argentina.
Sabazia is a genus of Colombian and Mesoamerican plants in the tribe Millerieae within the family Asteraceae.
Sclerocarpus is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae. Bonebract is a common name for plants in this genus.
Sinclairia is a genus of Latin American plants in the tribe Liabeae within the family Asteraceae.
Lagascea is a genus of flowering plants in the family Asteraceae. It occurs primarily in Mexico, but some species extend into Central America and one reaches north into the western United States. One species, L. mollis, has been widely introduced to other localities around the tropics and subtropics.
Lundellianthus is a genus of Mesoamerican flowering plants in the tribe Heliantheae within the family Asteraceae.
Montanoa is a genus of flowering plants in the tribe Heliantheae, within the family Asteraceae.
Otopappus is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae, primarily Mesoamerican but with one species from Jamaica.
Rensonia is a genus of Mesoamerican plants in the tribe Heliantheae within the family Asteraceae.
Perymenium is a genus of South American and Mesoamerican plants in the tribe Heliantheae within the family Asteraceae.
Philactis is a genus of Mexican plants in the tribe Heliantheae within the family Asteraceae.
Podachaenium is a genus of Mesoamerican plants in the tribe Heliantheae within the family Asteraceae.
Heiseria is a genus of flowering plants belonging to the family Asteraceae.