Noun: spear thistle
- European thistle with rather large heads and prickly leaves; extensively naturalized as a weed in the United States
"spear thistle made the field difficult to traverse";
- bull thistle, boar thistle, Cirsium vulgare, Cirsium lanceolatum
Derived forms: spear thistles
Type of: plume thistle, plumed thistle
Encyclopedia: Spear thistle