Thistle
According to a legend, an invading Norse army was attempting to sneak up at night upon a Scottish army's encampment. During this operation one barefoot Norseman had the misfortune to step upon a thistle, causing him to cry out in pain, thus alerting Scots to the presence of the Norse invaders. Some sources suggest the specific occasion was the Battle of Largs, which marked the beginning of the departure of King Haakon IV (Haakon the Elder) of Norway who, having control of the Northern Isles and Hebrides, had harried the coast of the Kingdom of Scotland for some years. Which species of thistle is referred to in the original legend is disputed. Popular modern usage favours Cotton Thistle Onopordum acanthium, perhaps because of its more imposing appearance, though it is unlikely to have occurred in Scotland in mediaeval times; the Spear Thistle Cirsium vulgare, an abundant native species in Scotland, is a more likely candidate. Other species, including Dwarf Thistle Cirsium acaule, Musk Thistle Carduus nutans, and Melancholy Thistle Cirsium heterophyllum have also been suggested.