If you are going anywhere by train during the summer months you will see this common weed of the railway tracks, Oxford ragwort (Senecio squalidus). This is not the common ragwort seen in meadows in late summer and autumn, it is a totally different species although superficially similar. This is an imported species brought in to Oxford, possibly to the University botanical gardens, as part of a research programme many years ago. I did hear the exact story some years ago and no can't remember it!
Like common ragwort these flowers turn into small dandelion type seed heads which are dispersed by wind. They were flowering near the main railway line in Oxford and the seeds were carried along the line in the slip stream of trains and now they are seen across the entire rail network.
They originate from volcanic areas in the Mediterranean region where they thrive on thin, dry soils so the chippings on railway lines is well suited to their needs.Oxford Ragwort: right on track