Reprinted from the Bulletin de la Société d'histoire naturelle du Doubs, no 18 (Séance du 20 décembre 1909)
At the time, "helvellas" probably included the things we now call Gyromitras.
also available as a separate off-print
This is perhaps his major work; it showed that chemical reactions of the fruiting body could be an excellent character in identifying mushrooms (and declaring new taxa!).