Holy Herb

And ... there by the way [King Bagdemagus] found a branch of an holy herb that was the sign of the Sangreal, and no knight found such tokens but he were a good liver.

– Malory

Strangely, Bagdemagus is unlisted among knights who later achieve the Adventures of the Grail. Gawaine supposedly kills him sometime during the Quest, although the details are fuzzy.