Senecio

Senecio /sɪˈniːʃi.oʊ/[2] is a genus of the daisy family (Asteraceae) that includes ragworts and groundsels. The scientific Latin genus name, Senecio, means "old man."

Senecio
Senecio vulgaris, an illustration from 1885.
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Asteroideae
Supertribe: Senecionodae
Tribe: Senecioneae
Subtribe: Senecioninae
Genus: Senecio
L.
Type species
Senecio vulgaris
Species

Some 1,250; see text.

Synonyms[1]

Dendrosenecio
Jacobaea L.
Vendredia Baill.
Culcitium Humb. & Bonpl

Variously circumscribed taxonomically, the genus Senecio is one of the largest genera of flowering plants. The traditional circumscription of Senecio is artificial, being polyphyletic, even in its new circumscription which is based on genetic data.[3][4] Despite the separation of many species into other genera, the genus still contains c. 1,250 species and is one of the largest genera of flowering plants.[5] As no morphological synapomorphies are known to determine which species belong to the genus or not, no exact species number is known. The genus has an almost worldwide distribution[3] and evolved in the mid- to late Miocene.[6]

Some species produce natural biocides (especially alkaloids) to deter or even kill animals that would eat them.

Senecio species are used as food plants by the larvae of some Lepidoptera species — see list of Lepidoptera that feed on Senecio. Pyrrolizidine alkaloids have been found in Senecio nemorensis[7] and in Senecio cannabifolius var. integrilifolius.[8]

Morphology

The flower heads are normally rayed with the heads borne in branched clusters, and usually completely yellow, but green, purple, white and blue flowers are known as well.

In its current circumscription, the genus contains species that are annual or perennial herbs, shrubs, small trees, aquatics or climbers. The only species which are trees are the species formerly belonging to Robinsonia occurring on the Juan Fernández Islands.[9]

Distribution

The genus Senecio is distributed almost worldwide.[3] It is one of the few genera occurring in all five regions with a Mediterranean climate. Furthermore, species are found in mountainous regions, including tropical alpine-like areas.

Phylogeny

Many genera and the whole tribe are in need of revision. Many species currently placed in the genus need to be transferred to other or new genera, and others have been retransferred to Senecio. In its new delimitation the genus is still not monophyletic.[3]

Genera that have been included are the following:[3]

Synonyms
Some of the popular succulent species that were included within Senecio, such as Curio repens (pictured) and Curio rowleyanus, are now placed in the Curio genus.

The following genera contain species that are or have been included within Senecio.[3]

Selected species
S. barbertonicus Succulent Bush Senecio
S. haworthii Woolly Senecio
Senecio kleiniiformis, Spearhead
Senecio madagascariensis, Fireweed
Senecio angulatus, Cape Ivy
Senecio macroglossus (wax ivy)
Senecio elegans (redpurple ragwort)
Main article: List of Senecio species

Formerly in Senecio

See also

References
  1. Germplasm Resources Information Network (GRIN) (2007-05-04). "Genus: Senecio L." Taxonomy for Plants. USDA, ARS, National Genetic Resources Program, National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved 2008-02-27.
  2. Sunset Western Garden Book, 1995:606–607
  3. Pelser, Pieter B.; Nordenstam, Bertil; Kadereit, Joachim W.; Watson, Linda E. (2007). "An ITS Phylogeny of Tribe Senecioneae (Asteraceae) and a New Delimitation of Senecio L". Taxon. 56 (4): 1077. doi:10.2307/25065905. JSTOR 25065905.
  4. Passalacqua, Nicodemo G.; Peruzzi, Lorenzo; Pellegrino, Giuseppe (August 2008). "A Biosystematic Study of the Jacobaea maritima Group (Asteraceae, Senecioneae) in the Central Mediterranean Area". Taxon. 57 (3): 893–906. doi:10.1002/tax.573018. JSTOR 27756716.
  5. Frodin, David G. (2004). "History and concepts of big plant genera". Taxon. 53 (3): 753–76. doi:10.2307/4135449. JSTOR 4135449.
  6. Pelser, Pieter B.; Kennedy, Aaron H.; Tepe, Eric J.; Shidler, Jacob B.; Nordenstam, Bertil; Kadereit, Joachim W.; Watson, Linda E. (2010-05-01). "Patterns and causes of incongruence between plastid and nuclear Senecioneae (Asteraceae) phylogenies". American Journal of Botany. 97 (5): 856–873. doi:10.3732/ajb.0900287. ISSN 0002-9122. PMID 21622451.
  7. Shi, Bao-Jun; Xiong, Ai-Zhen; Zheng, Shan-Song; Chou, Gui-Xin; Wang, Zheng-Tao (2010). "Two new pyrrolizidine alkaloids from Senecio nemorensis". Natural Product Research. 24 (20): 1897–901. doi:10.1080/14786419.2010.482058. PMID 21128163. S2CID 13202398.
  8. Ma, H; Yang, L; Wang, C; Wang, Z (2011). "Pyrrolizidine alkaloids of Senecio cannabifolius var. Integrilifolius". Zhongguo Zhong Yao Za Zhi = Zhongguo Zhongyao Zazhi = China Journal of Chinese Materia Medica. 36 (2): 166–8. PMID 21506416.
  9. Pelser, Pieter B.; Tepe, Eric J.; Kennedy, Aaron H.; Watson, Linda E. (2013-06-10). "The fate of Robinsonia (Asteraceae): sunk in Senecio , but still monophyletic?". Phytotaxa. 5 (1): 31–46. doi:10.11646/phytotaxa.5.1.2. ISSN 1179-3163.
  10. Norton, D.A. (1986). "Recent changes in the names of New Zealand tree and shrub species" (PDF). New Zealand Journal of Forestry. 31: 39–40.
  11. Sean Claes (2007-04-16). "Proceed With Caution". Kyle, Texas Daily Photo. Retrieved 2008-04-10.
  12. Rines, George Edwin, ed. (1920). "German Ivy" . Encyclopedia Americana.
  13. Ripley, George; Dana, Charles A., eds. (1879). "German Ivy" . The American Cyclopædia.
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