The Doors of Oerth
The assassin vine is a dangerous plant which grows both in and underground. It is suspendends itself from a tree, rock face or other such overhang by which uses its vines to kill victims and deposit the bodies near the roots for fertilizer. It consists of a main vine attached to the tree, about 20 feet long, with smaller, 5 foot long vines breaking off. It has both leaves and berries. The berries have a bitter taste and are used to make a heady wine despite being widely believed to be poisonous. They are harvested carefully by tended vines that are periodically pruned to prevent them from strangling their keepers.
A subterranean version of the assassin vine is darker in coloration to the ground dwelling one.