Living as I do in the city, many of the plants encountered daily are fairly tropical in origin. One of the most prominent of these is Oxford Ragwort (Senecio squalidus) which here, in my area of Newcastle, is particularly abundant in pavement cracks, walls, and other rocky places.
Clad in the vibrant yellow flowers typical of ragworts, Oxford Ragwort flowers all year round and never fails to brighten up a walk along our street, even in winter, when little else blooms and even the omnipresent Sheperd’s-purse has given up.
The rather healthy plant above was observed growing as a pavement plant, standing tall behind the bus stop at the end of my street.
Background
The genus name of ‘Senecio’ identifies this plant as a Ragwort and its species, squalidus, means ‘bad-smelling plant’
A member of the daisy family, Asteraceae, Oxford Ragwort is native to rocky and volcanic areas of Sicily, where it arose as a hybrid between two of the islands endemic species, Senecio aethnensis and Senecio chrysanthemifolius.
This species was introduced to cultivation in Britain from Sicily by William Shepard and in the 1700s where it soon made its way to Oxford Botanical Garden. By 1794 the plant had escaped the confined of the garden and could be found growly freely on Oxford’s city walls.
With the onset of rail travel, the plant found a new habitat and quickly spread to colonise the stone chippings used to line railway beds. From here, it was able to spread across the length and breadth of Britain, using railway tracks to reach urban areas across the country.
Oxford Ragwort is now widely distributed across the UK and, true to its nature, prefers seemingly barren habitats such as wasteground, city streets and walls. It is more widespread in the South of the UK but is also found in Northern England and Scotland.
An interesting paper on the introduction of Oxford Ragwort to the UK, courtesy of BSBI, can be found here.
Identifying Oxford Ragwort
Superficially similar to any other ragwort, Oxford Ragwort is a medium-sized plant with a well-branched stem. Its leaves are deep green and strongly lobed. Leaf shape in this species can, however, vary drastically from slightly serrate (saw-like) to double-pinnate.
It also has a more spreading habit than the Common Ragwort (Senecio jacobaea) and seldom grows to the same height as the latter species, preferring to grow outwards instead of up.
The flowerheads of this plant are bright yellow, usually with thirteen to fifteen ray florets but generally, look fairly similar to any other member of this family. Instead, the best way to identify Oxford Ragwort is to look at the bracts that form the ‘cup’ behind the flowerhead. In this species, these are tipped black. This applies to the longer inner bracts and much short outer ones.
For a more in-depth look at this species, a very useful page can be found here.