The Houses of Iszm — Jack Vance

The people of Iszm live in homes which are alive. Their dwellings are elaborate, hollow trees, wherein the very walls, floors- even furniture and plumbing- are all part of a living plant. For decades, inhabitants of other worlds, including Earth, have been trying to steal a female house seed, but every attempt has failed. This is the story of a most ingenious plot to carry off a prize worth billions: one seed from the Houses of Iszm.

Cover art by Howard Kistler