[Wikipedia] Europe, Asia, India, Africa native; Invasiveness: Silybum marianum is a species of thistle. It has various common names including milk thistle,[1] blessed milkthistle,[2] Marian thistle, Mary thistle, Saint Mary's thistle, Mediterranean milk thistle, variegated thistle and Scotch thistle (though not to be confused with Onopordum acanthium or Cirsium vulgare). This species is an annual or biennial plant of the family Asteraceae. This fairly typical thistle has red to purple flowers and shiny pale green leaves with white veins. Originally a native of Southern Europe through to Asia, it is now found throughout the world. Distribution and habitat Silybum marianum is native from around the Mediterranean and much of Europe to Central Asia and India; in Africa it reaches as far south as Ethiopia.[7] It is possibly native near the coast of southeast England. S. marianum has been widely introduced outside its natural range, for example into North America, Hawaii, Australia, New Zealand, Colombia where it is considered an invasive weed.[4][8][9] Additionally, today it also spreads as invasive plant in almost all of Europe as a consequence of field cultivation.[10] Silybum marianum establishes itself in sunny, warm ruderal meadows in regularly disturbed places such as rubble deposits, at the foot of south-exposed walls or villages and on urban fallow land or on cattle pastures. However, it does not prefer dry, stony soils.[10][11] Milk thistle has been potentially observed to modify fire regimes in its invasive range.[12][13] Its invasion into new habitats may also be encouraged by fire.[14] (contributed by Mary Ann Machi)