Senecio squalidus

Like all members of the family Asteraceae, Senecio squalidus has a composite flower head known as a capitulum. What look like single flowers are actually a cluster of florets, each petal or ligule being a flower, or floret, possessing its own stamen and capable of producing the specialized seed of the family Asteraceae, the parachute-like achene.{{cite web

| url = http://www.botany.hawaii.edu/Faculty/Carr/aster.htm

| title = Asteraceae (Compositae)

| access-date = 2008-02-14

| author = Dr. Gerald (Gerry) Carr, University of Hawaii, Botany Department

| author-link = University of Hawaii

| work = Vascular Plant Family Systematic Index

}}

Oxford ragwort is a short-lived perennial, a biennial, or a winter annual and grows in a branched straggling form to between {{convert|1.5|ft|m|sigfig=1}} and {{convert|3.3|ft|m|sigfig=1}} depending on conditions. S. squalidus prefers dry, disturbed places, cultivated and waste ground, walls and railway banks.{{cite web

| url = http://www.brickfieldspark.org/data/ragwortsqualidus.htm

| title = Oxford Ragwort - Senecio squalidus

| access-date = 2008-02-14

| author = Brickfields Country Park

| date = 2007-12-24

| work = Ask Brickfields Country Park a question

}} It flowers from March{{cite web

| url = http://www.ukwildflowers.com/Web_pages/senecio_squalidus_oxford_ragwort.htm

| title = Senecio squalidus Oxford ragwort

| access-date = 2008-02-12

| author = Peter Llewellyn

| date = 23 August 2004

| work = Wild Flowers of the British Isles

| publisher = Wild Flower Society

}} to December

and reproduces from seed.

;Leaves and stems: S. squalidus leaves are alternate, glossy, almost hairless and variable in form from deeply pinnately lobed to undivided with only the lower leaves being stalked. Stems and leaves resemble those of the common groundsel (Senecio vulgaris) with the exception that their lobes are more widely spaced.{{cite web

| url = http://www.defra.gov.uk/farm/wildlife/weeds/pdf/identify.pdf

| title = Identification of injurious weeds

| access-date = 2008-02-15

| author = Department for Environment, Food and Rural Affairs

| author-link = Department for Environment, Food and Rural Affairs

| date = 2000-03-07

| work = Farming: wildlife and plants

| publisher = United Kingdom Government

}}

;Inflorescence: S. squalidus has larger capitula than Senecio jacobaea and a more spreading habit. Yellow capitula of 10-14 petals in loose clusters. They are pollinated by insects. Ray corollas {{convert|.3|in|mm|sigfig=1}} to {{convert|.6|in|mm}} long, {{convert|.08|in|mm|sigfig=1}} to {{convert|.16|in|mm|sigfig=1}} wide.

:Oxford ragwort is self-incompatible and needs pollen from other plants with different self-incompatibility alleles;{{Cite journal

| last = Hiscock

| first = S.J.

| title = Genetic control of self-incompatibility in Senecio squalidus L. (Asteraceae): a successful colonizing species

| journal = Heredity

| issue = 1|pages = 85, 10–19

| pmid=10971686

| year = 2000

| volume = 85

| doi = 10.1046/j.1365-2540.2000.00692.x

| s2cid = 31529463

}}

{{Cite journal

| last = Hiscock

| first = S.J.

| title = Self-incompatibility in Senecio squalidus L. (Asteraceae)

| date = 2000

| journal = Annals of Botany

|pages=85, 181–190

}}

{{cite web

| url = http://www.bio.bris.ac.uk/research/plantrepro/alexandra.html

| title = Identification of genes regulating self-incompatibility in Senecio squalidus (Asteraceae).

| access-date = 2008-02-14

| author = Alexandra Allen

| author-link = University of Bristol

| publisher = University of Bristol, School of Biological Sciences

}} its own flowers possess a stigma with characteristics of both the “dry” and “wet” types.{{cite journal

|author1=Simon J. Hiscock |author2=Karin Hoedemaekers |author3=William E. Friedman |author4=Hugh G. Dickinson

| title = The stigma surface and pollen-stigma interactions in Senecio squalidus L. (Asteraceae) following cross (compatible) and self (incompatible) pollinations

| journal = International Journal of Plant Sciences

| volume = 163

| issue = 1

| pages = 1–16

| publisher = The University of Chicago Press

| location = University of Chicago, Hyde Park, Chicago

| date =January 2002

| doi = 10.1086/324530

|s2cid=84275629 | id =1058-5893/2002/16301-0001

|url=https://pdfs.semanticscholar.org/db85/356c3edc723f39faad28ee7af49e5f54cffc.pdf |archive-url=https://web.archive.org/web/20200227071915/https://pdfs.semanticscholar.org/db85/356c3edc723f39faad28ee7af49e5f54cffc.pdf |url-status=dead |archive-date=2020-02-27 }}

:The fruiting heads are often nodding.

;Seeds: Each pollinated Oxford ragwort floret matures into a bell to cylindrical shaped indehiscent achene, the shallowly ribbed fruit is light brown in colour and {{convert|.06|in|mm}} to {{convert|.12|in|mm|sigfig=1}} long. Each plant can produce approximately 10,000 fruits during the year.{{cite web

| url = http://nbn.nhm.ac.uk/nhm/bin/nbntaxa.dll/taxon_details?taxon_key=NBNSYS0000004367

| title = Details for Senecio squalidus L.

| access-date = 2008-02-14

| date = 1994-08-12

| work = The National Biodiversity Network's Species Dictionary

| publisher = Natural History Museum, London

}}

Image:Senecio squalidus flor.png|Mature capitulum

Image:Senecio squalidus fruto.jpg|S. squalidus developing capitula.

Image:Senecio squalidus hojas.jpg|Leaves and stalks of S. squalidus.

Image:Senetio-rupester.jpg|Capitula at different stages of development

As a Senecio and a diploid Senecio squalidus is part of a species group along with S. flavus, S. gallicus, S. glaucus and S. vernalis, which are widespread geographically and interesting for the study of genetic differences in relation to the environment and plant evolution.{{cite book

| author1= Peter Hollingsworth

|author2=Richard M. Bateman |author3=Richard Gornall

| title = Molecular systematics and plant evolution

| url = https://books.google.com/books?id=SVKN8V1cGg4C

| access-date = 2008-04-23

| year = 1999

| publisher = CRC Press

| isbn = 0-7484-0908-4

| pages = 504 pages

| chapter = Monophyly populations and species

| chapter-url = https://books.google.com/books?id=SVKN8V1cGg4C&pg=PA171

}}

File:Oxford ragwort in Liverpool-cropped.jpg.]]

This Senecio was introduced into Britain via Francesco Cupani and William Sherard in the years of their visit 1700, 1701 and 1702 from Sicily{{cite web

| url = http://www.dipbot.unict.it/ctnatura/vulcano/m_rossi.html

| title = Monti Rossi

| access-date = 2008-02-15

| author = University of Catania

| author-link = University of Catania

| language = it

}}

where it lives as a native on volcanic ash to the Duchess of Beaufort's garden at Badminton House. Later a transfer of the plant material to the Oxford Botanic Garden by the "Horti Praefectus" Jacob Bobart the Younger took place before his death in 1719,{{cite journal

| last =Harris

| first =S.A.

| author-link =Botanical Society of the British Isles

| title = Introduction of Oxford Ragwort, Senecio squalidus L. (Asteraceae), to the United Kingdom

| journal = Watsonia

| volume = 24

| pages =31–43

| publisher = Botanical Society of the British Isles

| year =2002

| url = http://archive.bsbi.org.uk/Wats24p31.pdf

| access-date =2008-02-14

}} providing perhaps a good indication of when this species of ragwort and other invasive species might have "escaped" and started to make their home in the greater British Isles. The Sicilian ragwort escaped into the wild and grew in the stonework of Oxford colleges (with the specific mention of the Bodleian Library) and many of the stone walls around the city of Oxford. This gave the plant its common name, "Oxford Ragwort".{{cite web

| url = http://www.bio.bris.ac.uk/research/plantrepro/oxford_ragwort.html

| title = The Oxford Ragwort Story

| access-date = 2008-02-13

| author = Plant reproduction and speciation group, University of Bristol

| author-link = University of Bristol

| publisher = University of Bristol, School of Biological Sciences

| archive-date = 11 April 2009

| archive-url = https://web.archive.org/web/20090411222925/http://www.bio.bris.ac.uk/research/plantrepro/oxford_ragwort.html

| url-status = dead

}}

Carl Linnaeus first described Senecio squalidus{{cite web

| url = http://linnaeus.nrm.se/botany/fbo/s/senec/senesqu.html.en

| title = Senecio squalidus L.

| access-date = 2008-02-14

| author = Swedish Museum of Natural History

| author-link = Swedish Museum of Natural History

| date = 2003-08-20

| work = Linnean herbarium (S-LINN)

}} in 1753, although there is a dispute as to whether the material came from the Botanic Garden or from walls in the city; the taxonomy for this species is further complicated by the existence of species with a similar morphology in continental Europe.

James Edward Smith officially identified the escaped Oxford ragwort with its formal name Senecio squalidus in 1800.

{{Quote box

| quote =The vortex of air following the express train carries the fruits in its wake. I have seen them enter a railway-carriage window near Oxford and remain suspended in the air in the compartment until they found an exit at Tilehurst.

| source =George Druce, 1927

| width = 50%

| align = right

}}

During the Industrial Revolution, Oxford became connected to the railway system and the plant gained a new habitat in the railway lines clinker beds, gradually spreading via the railway to other parts of the country. The process was accelerated by the movement of the trains

and the limestone ballast that provides a well-drained medium which is an adequate replica of the lava-soils of its native home in Sicily.{{cite web

| url = http://biosafety.abc.hu/unep/hyb.html#b4

| title = Plant Invasion and Inter-Specific Hybridization

| access-date = 2008-02-14

| author = Chris Gliddon

| author-link = United Nations Environment Programme

| date = 1998-02-12

| work = The impact of hybrids between genetically modified crop plants and their related species: biological models and theoretical perspectives

| publisher = Guide to Risk Assessment and Biosafety in Biotechnology, GRABB, United Nations Environment Programme

}}

During the 20th century it continued to spread along railway lines and found a liking for waste places and bombed sites after World War II which have a lot in common with the volcanic regions of its home.

Recently, this and other Senecio species and their differing tastes for self-incompatibility and self-compatibility have been the subject of study for the purposes of understanding the evolution of plant species as the genus finds new homes and pollen partners throughout the world:

• The origin of Senecio vulgaris var. hibernicus Syme was determined to be an introgression of Senecio squalidus into Senecio vulgaris subsp vulgaris
• The dual origin of S. cambrensis Rosser to both Wales and Scotland explained as being a product parenting by the diploid S. squalidus and the tetraploid S. vulgaris in both locations
• The willingness of S. squalidus to hybridize with Senecio viscosus Crisp & Jones and forms the sterile hybrid S. subnebrodensis Simk.
• The suggestion that S. squalidus is actually a hybrid of two other Sicilian Senecio: S. aethnensis Jan ex DC and S. chrysanthemifolius Poir.

Senecio squalidus grows on scree in mountainous regions of native range, and earned its common name Oxford ragwort for its willingness and ability to grow in similar habitat elsewhere in the world.

File:Range map-Senecio squalidus-Native.svg

Native{{cite web

| url = http://plants.usda.gov/java/profile?symbol=SESQ&mapType=nativity

| title = PLANTS Profile, Nativity of Senecio squalidus L.

| access-date = 2008-02-14

| author = Natural Resources Conservation Service (NRCS)

| author-link = Natural Resources Conservation Service

| work = The PLANTS Database

| publisher = United States Department of Agriculture

}}{{GRIN | accessdate = 2008-02-14 }}

:Senecio squalidus is considered to be a native of New Brunswick and Nova Scotia, Canada by the USDA Natural Resources Conservation Service while the same USDA other resource Germplasm Resources Information Network considers it to be native to Austria, Czech Republic, Slovakia, Germany, Switzerland, Albania, Bulgaria, Greece, Crete, Italy, Sardinia, Sicily, Romania, Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, Serbia, Slovenia.

Current{{cite web

| url = http://data.gbif.org/occurrences/searchCountries.htm?c&U+0050B;0&U+0050D;.s=20&c&U+0050B;0&U+0050D;.p=0&c&c&U+0050B;0&U+0050D;.o=13749824

| title = Occurrence search Classification includes Species: Senecio squalidus

| access-date = 2008-02-14

| author = Global Biodiversity Information Facility

| author-link = Global Biodiversity Information Facility

| work = Species Data

| publisher = GBIF Data Portal

}}{{cite web

| url = http://enciclopedia.us.es/index.php/Senecio_squalidus

| archive-url = https://web.archive.org/web/20040917112042/http://enciclopedia.us.es/index.php/Senecio_squalidus

| url-status = dead

| archive-date = 17 September 2004

| title = Senecio squalidus

| access-date = 2008-02-14

| language = es

| work = Artículo de la Enciclopedia Libre Universal en Español

}}

:Africa

::Northern Africa: Morocco

:America

::North America: New Brunswick, Nova Scotia, British Columbia, California

:Europe

::Northern Europe: Denmark, Germany, Republic of Ireland, Netherlands, Norway, Sweden, United Kingdom

::Middle Europe: Austria, Czech Republic, Hungary, Slovakia, Switzerland

::East Europe: Poland,

::Southeastern Europe: Albania, Bosnia and Herzegovina, Bulgaria

::Southwestern Europe: France, Spain

::South Europe: Croatia, Crete, Greece, Italy, North Macedonia, Romania, Sardinia, Serbia, Sicily, Slovenia

Range Maps

Image:Range map-Senecio squalidus-North America.svg|North America

Image:Range map-Senecio squalidus-Africa.svg|Africa

Image:Range map-Senecio squalidus-Europe.svg|Europe

S. squalidus is a food plant for some insects, for example:

Flies

:Gall flies (Diptera: Tephritidae):

:*Sphenella marginata

:*Trupanea stellata

:*Trypeta zoe{{cite web

|url=http://www.bioimages.org.uk/HTML/T606.HTM

|title=Senecio squalidus L. (Oxford Ragwort)

|access-date=2008-02-14

|publisher=BioImages: The Virtual Field-Guide (UK)

|url-status=dead

|archive-url=https://web.archive.org/web/20080907222712/http://www.bioimages.org.uk/HTML/T606.HTM

|archive-date=2008-09-07

}}

Fungi

Most Senecio, including S. squalidus are susceptible to rust and other fungus and mildews:

:Rust fungus Uredinales

:*Coleosporium tussilaginis - (Coleosporiaceae)

:*Puccinia lagenophorae - (Pucciniaceae)

:White rust Peronosporales

:*Albugo tragopogonis - (Albuginaceae)

:Sac fungus Ascochyta, Pezizomycetes

:*Ascochyta senecionicola - (Coelomycete)

:Powdery Mildew Erysiphales

:*Podosphaera fusca - (Erysiphaceae)

• Jacobaea incisa C. Presl
• Senecio glaber Ucria
• Senecio incisus (C. Presl) C. Presl
• Senecio laciniatus Bertol.
• Senecio nebrodensis auct., non L.
• Senecio rupestris Waldst. & Kit.
• Senecio squalidus d'Urv.
• Senecio squalidus Willd.
• Senecio squalidus M.Bieb.
• Senecio nebrodensis L. subsp. rupestris (Waldst. & Kit.) Fiori
• Senecio leucanthemifolius subsp. vernalis (Waldst. & Kit.) Greuter
• Senecio squalidus subsp. aethnensis (DC.) Greuter
• Senecio squalidus subsp. araneosus (Emb. & Maire) Alexander
• Senecio squalidus subsp. aurasicus (Batt.) Alexander
• Senecio squalidus subsp. aurasiacus (Batt. & Trab.) Alexander
• Senecio squalidus subsp. chrysanthemifolius (Poir.) Greuter
• Senecio squalidus subsp. eurasiacus (Batt. & Trab.) Alexander
• Senecio squalidus subsp. microglossus (Guss.) Arcang.
• Senecio squalidus subsp. rupestris (Waldst. & Kit.) Greuter
• Senecio squalidus subsp. sardous (Fiori) Greuter
• Senecio squalidus subsp. squalidus
• Senecio squalidus var. glaber (Ucria) FIORI

;Misapplied names:

:*Senecio nebrodensis sec. Fiori, A{{cite web

| url = http://mobot.mobot.org/cgi-bin/search_pick?name=Senecio+squalidus

| title = TROPICOS Web display Senecio squalidus L.

| access-date = 2008-02-14

| author = Missouri Botanical Garden

| author-link = Missouri Botanical Garden

| work = Nomenclatural and Specimen Data Base

| publisher = Missouri State Library

}}

{{Reflist|30em}}

• {{cite journal

| last =Harris

| first =S.A.

| author-link =Botanical Society of the British Isles

| title = Introduction of Oxford Ragwort, Senecio squalidus L. (Asteraceae), to the United Kingdom

| journal = Watsonia

| volume = 24

| pages =31–43

| publisher = Botanical Society of the British Isles

| year =2002

| url = http://archive.bsbi.org.uk/Wats24p31.pdf

| access-date =2008-02-14

}}

• {{cite journal

|title=A new British species, Senecio eboracensis (Asteraceae), another hybrid derivative of S. vulgaris L. and S. squalidae L

|url=http://www.watsonia.org.uk/Vol24p375.pdf

|journal=Watsonia

|last=Abbot

|first=R.J.

|author2=Lowe, A.J.

|year=2003

|volume=24

|pages=375–388

|access-date=2008-02-12

|url-status=dead

|archive-url=https://web.archive.org/web/20070927221840/http://www.watsonia.org.uk/Vol24p375.pdf

|archive-date=2007-09-27

}}

• {{cite book

| last = Hollingsworth

| first = Peter

|author2=Richard M. Bateman |author3=Richard Gornall

| title = Molecular Systematics and Plant Evolution

| url = https://books.google.com/books?id=SVKN8V1cGg4C

| access-date = 2008-04-23

| year = 1999

| publisher = CRC Press

| isbn = 0-7484-0908-4

| pages = 504 pages

| chapter = Monophyly populations and species

| chapter-url = https://books.google.com/books?id=SVKN8V1cGg4C&pg=PA171

}}

{{Commons category}}

• {{cite web

| url = https://maps.google.com/maps?q=rail+from+Oxford+to+Tilehurst

| title = Google maps Oxford to Tilehurst

| access-date = 2008-02-14

}}

• {{cite web

| url = https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=36186

| title = Senecio squalidus L.

| access-date = 2008-02-14

| author-link = Integrated Taxonomic Information System

| author =Integrated Taxonomic Information System Organization (ITIS)

| work = Integrated Taxonomic Information System on-line database

}}

• {{cite web

| url = http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250067513

| title = 31. Senecio squalidus Linnaeus

| access-date = 2008-02-14

| author = Flora of North America

| author-link = Flora of North America

| pages = Vol. 20 Page 548, 560, 561

}}

• {{cite web

| url = http://ww2.bgbm.org/EuroPlusMed/PTaxonDetail.asp?NameId=128285&PTRefFk=500000

| title = Details for: Senecio squalidus

| access-date = 2008-02-14

|author1=Botanic Garden |author2=Botanical Museum Berlin-Dahlem

|name-list-style=amp | author-link = Botanical Garden in Berlin

| work = Euro+Med PlantBase

| publisher = Freie Universität Berlin

}}

• {{cite web

| url = http://www.cnplx.info/nplx/nplx?page=coincident&taxon=Senecio+squalidus&available=t&action=t

| title = Plants that Grow with Senecio squalidus - oxford ragwort

| access-date = 2008-02-14

| publisher = California Native Plant Link Exchange

}}

• {{cite web

| url = http://www.floralimages.co.uk/psenecsqual.htm

| title = Senecio squalidus photographs for noncommercial use

| access-date = 2008-02-14

| author = Photographer: John Crellin

| date = 2006-04-22

| work = Flowers that grow in North-Western Europe

}}

• {{cite web

| url = http://www.habitas.org.uk/flora/species.asp?item=4367

| title = Senecio squalidus

| access-date = 2008-02-14

| work = Flora of Northern Ireland

| publisher = National Museums and Galleries of Northern Ireland and Environment and Heritage Service

}}

• {{cite web

| url = http://gallery.nen.gov.uk/image64145-e2bn.html

| title = Oxford Ragwort (Senecio squalidus)

| access-date = 2008-02-14

| author = Diane Earl

| date = 2006-09-26

}}

• {{cite web

| url = http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Senecio+squalidus

| title = Senecio squalidus L.

| access-date = 2008-02-12

| author = Calflora

| work = Information on California plants for education, research and conservation.

}}

{{Taxonbar|from=Q3955284}}

squalidus

Category:Environment of Oxfordshire

Category:History of Oxford

Category:Flora of Northern America

Category:Plants described in 1753

Category:Taxa named by Carl Linnaeus