Hungry grass, also known as fairy grass (féar gortach in Irish Gaelic) is a patch of cursed vegetation for which a lonely wanderer must keep a strong watch out. Anyone that unknowingly walks on it could be doomed to "perpetual and insatiable hunger." Whether the fearsome grass is cursed by a nearby corpse or planted specifically by wicked fairies to entrap is a matter of legend. Some travelers would always be sure to carry a bit of food to eat in case they found themselves amidst such a patch - nibbling was said to counteract the evil spell.
Another legendary herb to which magical properties are ascribed is called jumproot, which renders its user invisible, along with the power to open closed doors. The flower of the jumproot could only be obtained by theft from a hoopoe or woodpecker. Their nests would have to be found and the entrances stopped up, causing the bird to drop its precious mouthful of jumproot flowers in order to free its nest. Jumproot may be the same plant called magic flower in many fairy tales, which also renders invisibility and easy access to treasure caves to its eaters. Magic flower is described as blue or white, and either resembling the flowers of chicory or those of a lilly.
If a person was lucky enough to find and eat a fern seed, similarly strange powers could avail themselves. A fern seed was said to confer invisibility AND invulnerability, besides the obligatory treasure-finding powers, of course. But could only obtain such a seed on june 24th, St. John's night, with the help of particularly dangerous and arcane incantations. The fact that ferns don't reproduce by seed at all, only adds to the legend.
