Rayed Knapweed

While Ben was sitting yet another maths exam, I spent an hour and a half recording plants near Holywell, which is on the Lincolnshire limestone. This part of the county used to have some superb limestone grassland (and indeed still has some excellent fragments forming an SSSI) but much has been lost, and there is now very little chance of re-finding many of the rare species that were present in the 1940s.

Nevertheless, there were a few points of interest, notably an arable field margin with a good range of archaeophytes, including two species now classified as Vulnerable in Great Britain. 

Not far away I found this very colourful grassland, which I suspect has been at least partly sown. The intense purple flower is a knapweed -  a taxon that's surprisingly difficult to identify, partly because the taxonomists cannot decide whether it should be classified as one very variable species, or several species and subspecies. This particular population is composed largely of rayed blooms which are normally quite rare in native populations, but are readily available from seed merchants.