First flowers

The plant I thought was groundsel, Senecio vulgaris, has indeed proved to be so and, though still very small, has produced a flower.

Growing, as it is, in a rich compost, I am surprised that it is not much larger, but maybe it is aiming to get some seeds away as soon as possible. Groundsel is not common in our garden and I cannot remember seeing any for years so, as in the case of Surtsey island, it is not the closest plants that are the first colonists of the windowbox.