Corumbians

The people of Corumbia, whom the Sultan of Samandra turned into trees and bushes until the Yellow Knight set them free.

First named in The Yellow Knight of Oz, ch. 5

Verily, the Corabians and Corumbians are no more; all their land and treasure are added to your riches, and yet, for the last ten years, you have done nothing but grieve for a miserable, moth-eaten, wobbly-kneed camel!