This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
This vast genus contains several hundred species, but only one need occupy our attention here. The chief chaiacter is the involucre of one row of equal bracts. Flower-heads often destitute of ray-florets, as in S. vulgaris, the common Groundsel; or rayed, as in S. Jacobaea, the Ragwort. The name is derived from senex, an old man, in allusion to the abundant silvery pappus, or, as it is sometimes explained, the naked or bald receptacle.
1. S. elegans. - This commonly bears the name of Jacobaea, which belongs to another species. It is a very familiar plant in gardens, especially the double purple variety. There are also white, flesh, rose, and crimson varieties, which will come true from seeds. South Africa.