Reddit reviews Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia, and Alaska
We found 2 Reddit comments about Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia, and Alaska. Here are the top ones, ranked by their Reddit score.

Used Book in Good Condition
Pojar and Mackinnon is probably the best. Not purely edible but a great field guide with ethnobotanical tidbits.
This field guide is very good for native species. Many in the arboretums are not necessarily native species. I'd recommend a visit to the World Forestry Center near Washington Park (it's across from the Zoo and the Children's Museum) as well. It's has a lot about forestry practices and the forests of the Pacific Northwest. They have smoke-jumper and timber jack simulators that are pretty fun and a nice map of most all of the nature areas in the metro area.