A tall elegant plant when young, Carduus pycnocephalus, like many thistles becomes rather scruffy when older. The plant is covered in cobweb like hairs, which protect it from high heat and light levels; it is a Mediterranean species and although it is often found in lush vegetation in fields, and roadsides, it also survives in hot dry locations. The floating seeds of thistles are distributed widely and C. pycnocephalus was one of the earliest plants to be established in the sparse  soil on the edge of the new road over the mountain.

The small narrow flower heads are found singly or in groups of 2 or 3 at the top of branched stems. The term pycnocephalus means crowded heads. It is the most widely distributed member of the Carduus genus and the only one found as far south as Crete.