Gnomes are a species of plant-like creatures that assist the elves in day-to-day life. It's a symbiotic relationship, with the elves protecting the gnomes and the gnomes assisting the elves by growing plants and attending to any tasks that need doing.
It was also discovered that the same plague had been released on the gnomish leaders many years ago. The leaders died and became the Four Seasons Tree. Their dying wish was for the Council not to tell the other gnomes what had killed them.
Since then, the gnomish species recognizes no official leader. They are peaceful and in need, select an ambassador to represent them; this is seen in Lodestar at the drafting of the new ogre treaty.