blessed thistle

(noun) tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads; naturalized in California and South America. Synonyms: milk thistle, lady's thistle, Our Lady's mild thistle, holy thistle, blessed thistle, Silybum marianum.

(noun) annual of Mediterranean to Portugal having hairy stems and minutely spiny-toothed leaves and large heads of yellow flowers. Synonyms: blessed thistle, sweet sultan, Cnicus benedictus.