Nature writing is usually classified in that curious category of ‘non-fiction.’ It is categorized as what it is not, as an absence or lack, rather than what it is, a presence or being. Non-fiction is the other of fiction, without which it could not exist. Fiction requires non-fiction to constitute itself. Without ‘non-fiction,’ fiction could not and would not exist. Nature writing does not require fiction to exist. It is its own being, sufficient to itself, heterogeneous, and mixed with other genres. Nature is a matter of fact, not fiction, yet writing about it is often both factual and fictional, and nature has its own stories to tell that are sometimes fictional. The line between fact and fiction is often blurred, and deliberately so in nature and nature writing. Nature writing is faction. The facts of non-human nature and the facts and fictions of human culture coalesce in Thoreau’s nature writing in his use of tropes and figures, especially those that figure the human body as forms and phenomena in non-human nature, such as in his famous passage in Walden about sand-foliage formed by a railway cutting and the grotesque lower bodily stratum figured in terms of each other.