This is a herbaceous perennial which dies back to an overwintering rosette of leaves. It can be found in crevices, the base of walls and in paving - usually in shade or partial shade. It is not usually a problem weed and the foliage is quite attractive on an old wall.
The leaves are dark green with silky sheen and a slightly reddish tinge. They exude a milky sap when damaged and can be eaten raw in salads.
The smallish, yellow flowers occur between July and September. They are borne on wirey, multi-branched stems which can be up to 100 cm in height. Some pollination is by bees and flies, but mostly they are self-pollinated as they carry both male and female parts.
The seed are dispersed by the wind on a pappus which develops from the petals.

If growing in the open it is easily uprooted, but usually it is growing in a crevice and the whole root may not be removed.
Weedkillers to use:-
Treat any regrowth with Glyphosate.