Snow plants tend to be found growing with conifer trees, this is because conifers maintain a symbiotic relationship with mycorrhizae. Mycorrhizae grows around the roots of the conifers, helping them obtain water and minerals. In return, the conifer provides the mycorrhizae with photosynthate (a nutrient product of photosynthesis). Snow plants take advantage of this relationship, stealing photosynthate from the mycorrhizae.
Snow plants are edible, they can be prepared much the same way as asparagus. However, in California they are protected and you can get a big fine for picking or damaging them. You can even get fined for collecting the seeds.