Usually, it's the fauna that you have to worry about when you're going adventuring. But the flora can sometimes be just as dangerous. Skirmisher Publishing has released Three Alien Vegetable Monstrosities that you can add to your sci-fi or fantasy game sessions to give the vegetarians in the group something to think about.
From the website:
This publication includes entries for three dangerous and creepy plant monsters that can be used in a wide variety of science fiction, modern, horror, and post-apocalyptic scenarios. They are stat'ed for the Pathfinder RPG but can easily be adapted for use with any d20/OGL system games.
Monsters in this supplement include the Chomper, a tough beast that has multiple variants; the Sucker Plant, which can menace anything that makes the mistake of getting too close to it; and the Man Trap, a surprisingly charming carnivorous organism.