The pipe cactus is like an iceberg, if you replace the ice with cactus and the sea with sand. A pipe cactus runs deep, deep into the sands, its roots grasping for any moisture it can find. That moisture often can be found at the bottom of quicksand, or on the bedrock, many metres below the surface. A pipe cactus is one of the few that can 'pipe' that moisture up.
Many a moon garou has tried to suck that moisture up through the 'pipe' of the cactus, like a natural well. The pipe cactus has evolved counter-measures to that particular ploy, including valve-like structures up its stem, and, you know, spikes.