Thistle do nicely

The boorish cousin of the dainty daisy, the emblem of Scotland was historically blamed for donkey flatulence and recommended as a treatment for depression, discovers

- John Wright

BANE of agricultural land, despoiler of picnics and of little practical value, it is odd that the ever-troublesome thistle has, nevertheless, earned our affection. Respect, as everyone knows, is something they uncompromisingly demand. What counts as a thistle? If you will forgive the unavoidably clumsy caveats, they are usually prickly members of some of the tribe of plants known as the Cardueae, one of the many tribes in the daisy family. Most British thistles belong to the genera Cirsium and Carduus, the first including the creeping, spear, meadow, marsh, dwarf (or stemless or picnic) and woolly thistle. The second group houses the musk, welted and slender thistle. There are also other familiar thistles within the Cardueae family, such as the Scottish thistle, milk thistle and carline thistle, and among the members that are not thistles are burdocks and knapweeds. Now you know.

With so few resident thistles, it is surprising how difficult they are to differentiate. I cannot provide a complete thistle primer, but a simple tip for telling a Carduus from a Cirsium will help. As it is the seed hairs that are distinct, the specimen under investigation must be ready to release its seeds. In Carduus, they are simply straight hairs, in Cirsium they are 'feathery', each hair bearing many smaller ones radiating outwards at 90 degrees.

Purple reign

‘A fig for the flowers in your lady-built bowers/The strong-bearded, weel-guarded Thistle for me!’ This snippet of patriotic song conspicuously fails to say ‘meadow thistle’ or ‘creeping thistle’, only ‘thistle’. As we have seen, there is a Scottish thistle—Onopordum acanthium, to be precise, otherwise known as the cotton thistle. It was declared the emblem of Scotland in 1822 by Sir Walter Scott during a visit to the country by George IV. Surely this is the one?