[treecreeper]

I've spent the day looking at scores of common ragworts Senecio jacobaea. I am certain now that Tormentil's plant is Senecio jacobaea as identified by davidbr and aeshna5. With one exception all the plants I looked at had black tips on the involucre bracts, but in some cases only just. Most books use this feature as a diagnostic for some species of Senecio, but I'm left wondering if it's much use.