An ashen grey willow with pale leaved tendils obscuring it's gnarled trunk. Sitting in the mire of great swamps, rare even in it's natural environment. The Banshee Willow's bark is known to have magical properties. Travelers beware, these trees seem to attract ghosts and other unsavory undead.
Demontrumpets, as illuded to by the name, are not normal plants, but are plants who hold their origin in the Abyss. Perhaps brought by summoned demons, perhaps created by a dark god for some purpose, perhaps simple plants mutated by an artifact of great evil.
A large, ruby-red pepper, found in dry regions; much prized by alchemists and gourmands alike.
Magic is the lifeforce of all living creatures, and it is from it that all life is made - in areas with lots of undead, magic might actually be missing or weak, which puts a whole new spin on how dangerous the undead are. Even simple zombies can be troublesome if you're relying on mages and you hit a pocket of undead making a low-magic zone...