74 



The Canadian Field-Naturalist 



[Vol. XXXIV. 



DEADLY POISONOUS MUSHROOMS. 



By R E. Stone, M.Sc, Ph.D. 



Department of Botany, Ontario Agricultural College. 



Nearly every year, especially in the late summer 

 and early autumn our woods and fields bear a 

 crop of mushrooms. Many people would enjoy 

 collecting and eating them, but since some of these 

 fungi are deadly poisonous, many are deterred from 

 gathering them because they are unable to tell 

 with absolute certainty the edible from the poison- 

 ous forms. 



In Ontario there are at least two hundred (200) 

 kinds of fleshy fungi of which sixty (60) occur 

 in abundance, and are large enough to collect for 

 eating. Unfortunately a few of these are deadly 

 poisonous and sometimes occur in quantity. Some 

 of these are also very attractive and always clean. 



is edible. Unfortunately some of the deadly poison- 

 ous kinds will peel beautifully. Others say, collect 

 only those that are pink underneath; this although 

 good advice, unfortunately limits one's choice to 

 but a few of the edible kinds. Still others say, 

 never collect mushrooms in the woods but only in 

 the fields, yards and gardens. This is again, excel- 

 lent advice but also limits our choice and eliminates 

 many of the very best. There is no simple rule 

 that can be applied ; one must learn to know the 

 poisonous forms the same as he knows other plants. 

 In order to enable mushroom lovers to avoid the 

 dangerous forms, the most dangerous forms are de- 

 scribed and figured below. 



Kix- 1- — V\x AKaiif (.Amanita muscaria. Linn). I>t'ai]ly roi.sonou.s. 

 From Bulletin 26:i, Ontario Department of Agriculture, Ontario Agricultural College. 



The question is often asked — "How do you tell 

 a mushroom from a toad stool" meaning by toad 

 stool a form that is either inedible or poisonous. 

 There is no simple rule. Occasionally one sees 

 published the old silver test. This is an old idea and 

 still prevalent in some places, especially Italy. In 

 olden days silver was accredited with many magic 

 properties, especially that of turning black in the 

 presence of malign influences, hence, silver would 

 turn black in the presence of poison. This test can 

 not, of course, be relied upon. Another test often 

 spoken of is the peeling test. Some of our mush- 

 room gatherers say that if the outer skin of a mush- 

 room can be peeled off readily, that the mushroom 



Fly Agaric (Amanita muscaria, Linn). Dead- 

 ly poisonous. 



This fungus appears in July and August in 

 groves and open woods or along roadsides near 

 trees, usually preferring rather poor soil. (Fig. I.) 

 It is called "Fly Agaric" because an infusion of the 

 plant was at one time used as a fly poison. The 

 plant is typically large and handsome. 



The cap is 3 to 5 inches broad, rounded when 

 young, nearly flat when old, yellow or orange or 

 even bright red in color, and covered with numerous 

 angular scales, which are white or light yellow in 

 color and can be easily brushed off. As the cap 

 becomes old it fades out, so that it may become 



