162 Canadian Record of Science. 



I shall begin my descriptions with the fourth series, 

 as that contains the well-known field mushroom or 

 Agaricus Campestris. This is found in many parts of 

 Canada. I have found it at Banff and am told that it 

 grows in great profusion about Winnipeg, Toronto and 

 Montreal, and in favorable seasons we find a great 

 many about St. Andrews, and on a trip through New 

 Brunswick and Nova Scotia some few years ago we 

 saw them in abundance in many pastures. 



It is the type of the Agaricaeeae, and as such I shall 

 give it a fuller description than any other. 



It is the fruit of a vine-like tangle of white 

 threads, called the mycelium which penetrates the soil 

 just below the surface. From little joints . in 

 this mycelium, tiny white dots like pin-heads are 

 formed, and under favourable circumstances or condi- 

 tions of warmth and moisture, they develop into little 

 button-like knobs, which push through the ground and 

 quickly develop into the full grown mushrooms and as 

 quickly perish, the preparation for their existence has, 

 however, been going on for weeks or months. 



The parts of an agaricus are the stem or stipe, the 

 cap or pileus, the ring or aimiilus. 



The cap is the expanded part which bears the 

 hymenium or spore-surface, which in all of the Agari- 

 caeeae is on the under surface of the cap, and consists 

 of plates or folds called gills, this in the button stage 

 of the Agaricus and a few other genera is covered by 

 a membrane which connects the edge of the cap with 

 the stipe, and as the plant expands the membrane 

 breaks away, some portions remaining attached to the 

 stem forming the ring or annulus, and some remaining 

 connected with the cap, giving a ragged appearance to 

 its edges. 



In the early stages the gills are pink, gradually be- 

 coming darker until they become a dark chocolate 

 brown and later nearly black. 



This change of color is caused by the gills becoming 

 covered with the brown-purple spores. 



If the stem of a mushroom is cut off and the cap is 



