PSALLIOTA CAMPESTR1S 451 



peridium separating slightly from the stipe and columella after 

 the manner of an agaric such as a Mushroom. The photographs 

 reproduced in Figs. 153, B, and 155 show common types of mature 

 fruit-bodies, while those reproduced in Figs. 153, C, and 154 show 

 an amount of expansion beyond the ordinary. 



After a median vertical section had been made through a fruit- 





j 



. 



FIG. 154. Secotium agaricoides. A vertical section through a ripe 

 fruit-body which has expanded on the left side only. Exposed 

 to view are: the peg-like stipe and its extension, the colu- 

 mella ; the peridial flesh ; and the pulverulent, spore -enclosing 

 gills. Collected by W. S. Odell at Ottawa. Photographed by 

 the Photographic Division of the Canadian Geological Survey. 

 Natural size. 



body freshly gathered at Winnipeg, the upper part of the columella 

 turned brown on bruising and the anastomosing gill-plates greenish. 

 Conard 1 describes the general development of the fruit-bodies 

 of Secotium agaricoides in the following words : ' The youngest 

 specimens are nearly globular, white, and smooth. Then comes a 

 ' button stage,' with the upper portion slightly larger than the stalk 

 and the surface still smooth. Later, the fertile portion increases 

 greatly in height and diameter, leaving the free stalk as a mere 

 basal projection. The superficial brown scales of the peridium 

 appear only when near full maturity. The spores are fully mature 



1 H. S. Conard, "The Structure and Development of Secotium agaricoides.'' 

 Mycologia, vol. vii, 1915, p. 95. 



