A translation of Die Röhrlinge und Blätterpilze Band II, 4th edition, 1978 (part of Gams’s Kleine Kryptogamenflora)

Keys to agarics (mushrooms and toadstools) and covering a huge number of taxa. It is very terse by today’s standards.

If anything, its fault was that it was a key to published names rather than to real-world fungi - you could waste a lot of time trying to decide which of two synonyms better fitted your find. Furthermore, the alternatives you had to choose between were often either unrelated (eg with a ring versus on wood) or overlapping (eg brown versus dark brown). Nevertheless it was extremely useful in its day.