Senecio

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Senecio Template:IPAc-en<ref>Sunset Western Garden Book, 1995:606–607</ref> is a genus of flowering plants in the daisy family (Asteraceae) that includes ragworts and groundsels.

Variously circumscribed taxonomically, the genus Senecio is one of the largest genera of flowering plants.

DescriptionEdit

MorphologyEdit

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.<ref>Template:Cite journal</ref>

ChemistryEdit

Pyrrolizidine alkaloids are found in all Senecio species. These alkaloids serve as a natural biocides to deter or even kill animals that would eat them. Livestock generally do not find them palatable.<ref>Template:Cite book</ref> Senecio species are used as food plants by the larvae of some Lepidoptera species that have developed tolerance for these alkaloids.

TaxonomyEdit

The traditional circumscription of Senecio is artificial, being polyphyletic, even in its new circumscription which is based on genetic data.<ref name="Senecioneae" /><ref>Template:Cite journal</ref> Despite the separation of many species into other genera, the genus still contains Template:Circa species and is one of the largest genera of flowering plants.<ref name="Frodin">Template:Cite journal</ref>

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<ref name="Senecioneae" /> and evolved in the mid- to late Miocene.<ref>Template:Cite journal</ref>

PhylogenyEdit

As of 2007, 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.<ref name="Senecioneae" />

Genera that have been included are the following:<ref name="Senecioneae" />

Aetheolaena
Culcitum
Hasteola
Iocenes B. Nord.
Lasiocephalus Willd. ex Schltdl.
Robinsonia

SynonymsEdit

File:Senecio serpens 06.jpg

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

File:Senecio.barbertonicus.7074.jpg

S. barbertonicus Succulent Bush Senecio

The following genera contain species that are or have been included within Senecio.<ref name="Senecioneae">Template:Cite journal</ref> Template:Div col

Antillanthus B. Nord.
Barkleyanthus H. Rob. & Brettell
Brachyglottis J. R. Forst. & G. Forst.<ref name="RecentChanges">Template:Cite journal</ref>
Canariothamnus B. Nord.
Curio P.V. Heath
Dauresia B. Nord. & Pelser
Dendrophorbium C. Jeffrey
Dendrosenecio (Hauman ex Hedberg) B. Nord. - Giant groundsels occurring in the high altitude areas of East Africa
Dorobaea Cass.
Dresslerothamnus H. Rob.
Elekmania B. Nord.
Herreranthus B. Nord.
Hubertia Bory
Jacobaea Mill.Leonis B. Nord.
Ligularia
Lundinia B. Nord.
Mesogramma DC.
Monticalia C. Jeffrey
Nelsonianthus H. Rob. & Brettell
Nesampelos B. Nord., nom. inval.
Oldfeltia B. Nord. & Lundin
Packera Á. Löve & D. Löve
Pentacalia Cass.
Pippenalia McVaugh
Pittocaulon H. Rob. & Brettell
Pojarkovia Askerova
Psacaliopsis H. Rob. & Brettell
Pseudogynoxys (Greenm.) Cabrera
Pseudojacobaea (Hook. f.) R. Mathur
Roldana La Llave
Sinosenecio B. Nord.
Synotis (C. B. Clarke) C. Jeffrey & Y. L. Chen
Telanthophora H. Rob. & Brettell
Tephroseris (Rchb.) Rchb.
Vendredia Baill.<ref name="GRIN" />
Zemisia B. Nord.<ref name="GRIN">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> Template:Div col end

EtymologyEdit

The scientific name, Senecio, derives from the latin 'senex' wich means "old man".

Selected speciesEdit

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Senecio ampullaceus — Texas ragwort, Texas squaw-weed, Texas groundsel, clasping-leaf groundsel<ref name="kyledaily">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

Senecio angulatus L.f. — creeping groundsel
Senecio antisanae
Senecio arborescens
Senecio barbertonicus Klatt — succulent bush senecio
Senecio bigelovii — nodding groundsel
Senecio bosniacus G. Beck — Bosnian ragwort
Senecio brasiliensis (Spreng.) Less. — flor-das-almas
Senecio candicans — angel wings
Senecio cambrensis — Welsh groundsel, Welsh ragwort
Senecio crassissimus
Senecio elegans — purple groundsel
Senecio falklandicus
Senecio flaccidus Less. — Douglas senecio, threadleaf groundsel, threadleaf ragwort
Senecio gallicus Chaix — French groundsel
Senecio glaucus L. — Jaffa groundsel
Senecio howeanus
Senecio inaequidens — South African ragwort
Senecio iscoensis — Hieron.
Senecio keniophytum
Senecio lamarckianus
Senecio leucanthemifolius Poir. — coastal ragwort
Senecio madagascariensis — Madagascar ragwort
Senecio macroglossus — Natal ivy, wax ivy
Senecio neowbsteri Olympic Mountain groundsel
Senecio patagonicus
Senecio pauciradiatus
Senecio pokohinuensis — Mokohinau groundsel
Senecio pulcher
Senecio sanmarcosensis
Senecio scandens — climbing Senecio
Senecio squalidus — Oxford ragwort
Senecio trapezuntinus
Senecio triangularis — arrowleaf groundsel
Senecio tropaeolifolius — false nasturtium
Senecio vaginatus
Senecio vernalis — eastern groundsel
Senecio viscosus — sticky ragwort
Senecio vulgaris — common groundsel, old-man-in-the-spring

Formerly in Senecio

Brachyglottis greyi (as S. greyi)
Pericallis × hybrida (as S. cruentus)
Rugelia nudicaulis — Rugels ragwort

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DistributionEdit

The genus Senecio is distributed almost worldwide.<ref name="Senecioneae" /> 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.