The Cardueae are a tribe of flowering plants in the daisy family (Asteraceae) and the subfamily Carduoideae. Most of them are commonly known as thistles; four of the best known genera are Carduus, Cynara, Cirsium, and Onopordum.

Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the plant – on the stem and on the flat parts of the leaves. These prickles protect the plant from herbivores. Typically, an involucre with a clasping shape similar to a cup or urn subtends each of a thistle's flower heads. The typically feathery pappus of a ripe thistle flower is known as thistle-down.