“ The carline thistle is Carlina vulgaris, a member of the same family, as is also the sow-thistle, Sonchus oleraceus. The great objection to thistles from an agricultural point of view resides in the freedom with which they produce seed, and in the vigour of their underground growth, which makes their uprooting a matter of difficulty. Partial uprooting may, indeed, in the case of the perennial species, increase the mischief, for each fragment left behind may grow into a distinct plant. ”