Spiny Flowers.

Image of a "Silybum marianum, colloquially identified as Carduus marianus, known as milk thistle, is an annual or biannual plant of the Asteraceae family. 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. The medicinal parts of the plant are the ripe seeds." (Source Wikipedia). At Murcia is known as Cardo Borriquero.
This plant can be found in fields, roadsides.
It seems that this plant has healing properties of the liver, but also has side effects such as nausea.
More info: Wikipedia.