Murrill: Poisonous Mushrooms 



257 



The characters and tests used to distinguish poisonous mush- 

 rooms have been most varied and curious, and nearly always 

 mixed with queer traditions and superstitions. If the percentage 

 of deadly forms were not so small, probably not over one per 

 cent., the fatalities from this source would have undoubtedly 

 been much more numerous. The only safe rule to follow is the 

 one used with other plants, namely, to know each species accu- 

 rately before eating it. Even the rules carefully formulated by 

 mycologists are almost certain to prove unreliable as men grow 

 bolder and attempt to eat species not previously tested, because 

 everything that is known in this field has been discovered by ex- 

 periment, and predictions or generalizations of any kind are both 

 unscientific and unsafe. It may be possible to forecast accurately 

 the discovery of a new chemical element with given properties, 

 but mushrooms have not yet been reduced to that basis. The 

 sweeping statement that brown-spored and black-spored species 

 are always safe was only recently controverted by the accidental 

 discovery of the poisonous properties of Inocybe infida. The 

 genus Amanita, while including the principal deadly species, con- 

 tains also many that are widely used as food, the dififerences often 

 being so slight as to be overlooked by experienced collectors. 



♦ The genus Amanita is distinguished from other white-spored 

 genera by the presence of a universal veil which encloses the 

 entire sporophore in its young stage and remains either at the 

 base of the stipe or as warts on the surface of the pileus when 

 the sporophore is mature. Over thirty American species are 

 listed, but hardly half of them are worthy of the rank, and only 

 five of these are known to be poisonous. The other species men- 

 tioned in the following discussion belong to various and widely 

 different genera. 



Discomycetes 



Most of the cup-fungi that are large enough to be called mush- 

 rooms " are edible, only one conspicuous species, Gyromitra escu- 

 lenta, having a questionable reputation, and this only in old or 

 decaying specimens, which have been found to contain helvellic 

 acid, a deadly poison similar to that occurring in Amanita phal- 

 loides. Although young and fresh specimens of Gyromitra escu- 

 lenta have been frequently eaten without harm, it is wise to 

 refrain from using the plant for food in any form. 



