This slender member of the Asteracea is well-named, for its leaves are edged with sharply-pointed teeth, like the blade of a saw. These readily distinguish Saw-wort from Common and Chalk Knapweed (Centaurea nigra
and C. debeauxii
respectively), which have similar flowers but lack serrated leaves.
Look out for it in herb-rich chalk and neutral grassland in August and September, when it is in full flower. As a rule of thumb, this species is strongly associated with the highest grassland diversity.