My grandma gave me this German wild foods book a decade or three ago. It was written in 1947, after WWII, at a time when there was a shortage of all kinds of foods. It includes common and nontoxic fungi, wild foods, tea plants and berries. It was written for the layman, and meant to help stave off famine while making sure that people wouldn't die by picking toxics. It even includes recipes (compleat with things like "eggs (if available)").
My grandma liked it and used it - she bought it when it was new. In turn, I've liked it and used it - and now that I've scanned it you can like it and use it, too. Of course it's in German, and if you want to read it but can't, well, learning new languages never hurt anybody.
I've reformatted the text quite a bit, because oodles and doodles of indents are hard to do in html (or, not all that hard to do, but wasteful of bandwidth). The info on fungi could be outdated - don't trust the edibility info there. I've put in comments on newfound toxicity among the bits about plants.
Aus Wald und Feld den Tisch bestellt, 1947, von Prof. Dr. Walther Schoenichen.