Wood-moss was a resilient plant that grew as clumps in moss-covered soil on the planet called Ylesia. As their primary food source, the herbivorous reek, which was native to Ylesia, consumed wood-moss, resulting in the development of strong jaws and teeth for harvesting it, along with cloven feet featuring front claws for unearthing the plant. Reek herds were fiercely protective, defending their wood-moss patches to the death against rival herds, ultimately leading to their evolution into formidable fighters.
Wood-moss also existed on the Codian Moon, although in significantly smaller amounts than on Ylesia. Ranchers had relocated many reek herds there to harvest them for meat by 22 BBY. The scarcity of wood-moss caused the reek to become even more aggressive, and the ranchers eventually discovered that they could force the herbivores to consume meat if they were starved for a sufficient period.
Within the current Star Wars canon, the first mention of wood-moss occurred in the 2018 reference book titled Star Wars: The Complete Visual Dictionary, New Edition, authored by Pablo Hidalgo and David West Reynolds. The moss had its origins in the Star Wars Legends continuity, where it initially appeared in the 2002 reference book Star Wars: Attack of the Clones: The Visual Dictionary, which was also written by Reynolds.
- Star Wars: The Complete Visual Dictionary, New Edition (First mentioned)
- " Geonosis and Other Planets in the Outer Rim " — Star Wars Encyclopedia