Blessed thistle; Cnicus benedicta. Handcoloured botanical illustration drawn by William Clark and engraved on steel by Weddell from John Stephenson and James Morss Churchill's 鈥楳edical Botany: or Illustrations and descriptions of the medicinal plants of the London; Edinburgh; and Dublin pharmacopoeias;' John Churchill; London; 1831. William Clark was former draughtsman to the London Horticultural Society and illustrated many botanical books in the 1820s and 1830s.