The layered symbolism that has developed surrounding the thistle flower begins with its spine-like stems and spiky blossom connected with the crown chakra or third eye. The color purple (named from this predatory mollusk!)has long been associated with royalty, good judgment and spiritual enlightenment. You can read more about additional connections that have been drawn throughout time and by varying cultures here.
Or you might recall or rediscover your own experience of the thistle through this painting.