Meaning : Any of several Old World coarse prickly-leaved shrubs and subshrubs having milky juice and yellow flowers. Widely naturalized. Often noxious weeds in cultivated soil.
Synonyms : sow thistle
Meaning : Tall Old World biennial thistle with large clasping white-blotched leaves and purple flower heads. Naturalized in California and South America.
Synonyms : blessed thistle, holy thistle, lady's thistle, our lady's mild thistle, silybum marianum