

Many plants are called thistles and have in common prickliness. Stems, flowers, or leaves have bristly spikes, a protective characteristic rendering them unpleasant to handle (or eat, if you graze).
Thistles belong to the Asteraceae family, making them distant cousins of sunflowers, asters, and daisies. Different types include edible cardoons (Cynara); ornamental globe thistles (Echinops); weeds (Cirsium and Carduus); and the controversial Scottish thistle (Onopordum acanthium), which is Scotland’s national flower but invasive in the US.