“ The forests, the swamps, the lands lost to wilderness, fang, and willow. These lands are home to the creatures of wiing, tooth and claw. Some far more capable of fending off the hominids, others still, are less fortunate, falling prey to spears, arrows, and dogs. As the hominids encroach upon the sacred woodlands and miry bogs there are times that the thorns and vines are animated by the spirit of the land in order to fight. In this way the mysterious guardians are formed. In the shapes of wolves, bears, and many other greater and more terrible beasts, each with eyes of glowing emerald. Fiercely defending creatures of burrow and glade.”
“ A desolate region is almost entirely without normal vegetation. Local plants are able to unroot themselves and crawl along the ground in search of water and fertile soil. The inhabitants fence their crops in to keep them from wandering off and put heavy stone thresholds in the doorways of their huts to keep wayward plants out.
The plants sense by chemical cues, lacking sight or hearing, and tend to avoid herbivores or anything that smells of 'dead plants'. Characters with horses are likely to be unwelcome among the locals.”
“ Feral teenagers:
Teenagers who run away from home to live in the wilderness may become feral. As they become more and more feral, they gain some supernatural powers (a la Peter Pan - ability to fly, things they imagine come true - possibly quite powerful), but at the expense of their humanity and ability to speak, comprehend complex subjects, etc. Maybe they have a leader: the most feral of them all.
A regression into a fantasy childlike state.”