Fydre was a charismatic and vocal follower of the Old Green (Druidic) Religion. He would often be found in the cities and town trying to get people to return to “the proper pantheon of The Land”, which to be honest, nobody had been following for a good century. Soon after he faded from public view, the weed known as Fydres (or Fydre’s Revenge, Fydre’s Curse, Elven Curse) was noticed in volume. In truth, nobody knows the origins of this plant. It could be something from far, far away born on the wind. It could of been his dying curse.
Fydres is a plant that grows in cracks and compressed earth (out from under heavy things). It is an ugly vine that sends runners out and sprouts a grass-like cluster everywhere it takes roots to ground. It grows like a weed in the unlikliest of places. It is a hardy vine that is fiberous and has tiny pickles. In short, it is a nightmare to remove.
The weed slowly becomes destructive. It expands cracks it grows in, it seems to pull runners tigher with age displacing stones. Thus Fydre disrupts cobblestone streets, helps displace the walls it grows upon, and can help to “decompose” abandoned and not so abandoned places. In short it is the bane of every urban environment of the region.
Any ruins, historical or recent, quickly become overrun by these plants. They crumble to rubble at an alarming rate with the assistance of the plants.
It does not effect just buildings. It is also the bane of any rock formation, as the same “features” helps break down and aid in the errosion of rocks. (Admittedly this does happen more slowly.) Thus making a number of mountain passes and Dwarven holds more dangerous.
It is this fact that it breaks down cliffs and rockfaces that make scholars think it is not some kind of magically created retribution plant, but simply transplanted spores from elsewhere.