Senecio Squalidus - History

History

This Senecio was introduced into Britain via Francisco Cupani and William Sherard in the years of their visit 1700, 1701 and 1702 from Sicily where it lives as a native on volcanic ash to the Duchess of Beaufort's garden at Badminton. Later a transfer of the genetic material to the Oxford Botanic Garden by the "Horti Praefectus" (the title still given to the head gardener at the Oxford Botanic Garden) Jacob Bobart the Younger before his death in 1719 (which is also the same year that Bobart retired as Horti Praefectus and 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".

Carolus Linnaeus first described Senecio squalidus 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.

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.

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.

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 home.

Recently, this and other Senecio 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 was determined to be an introgression of Senecio squalidus into Senecio vulgaris subsp vulgaris
• The dual origin of S. cambrensis 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 and forms the sterile hybrid S. subnebrodensis
• The suggestion that S. squalidus is actually a hybrid of two other Sicilian Senecio: S. aethnensis and S. chrysanthemifolius .