Dandelion

Dandelions, although now currently thought of as a weed to be fed to cows, rabbits or guinea pigs, can actually be used in salads (both the flower and leaves).

Asside from culinary uses, apparently dandelion makes a nifty purple dye. But it mustn't be very colourfast, as it's not particularly talked about by people who do period dying.

see also: other herbs