The cactus is in the tree in the sense of an epiphytic cactus, which grows on another plant for support rather than in soil. A common example is a rainforest cactus that roots in bark crevices and collects moisture from the air.

What that means

  • It is not a parasite; it uses the tree as a perch, not as a food source.
  • The cactus usually sits in small pockets of organic matter on branches or in bark cracks.
  • The tree is basically acting like a living scaffold.

If you meant a place

If you meant a specific “cactus in the tree” from a post, image, or forum joke, the most likely answer is still: on the branches or in the bark crevices , not hanging from leaves or inside the trunk.