72 RESEARCHES ON FUNGI 



However, none of the basidia produce sterigmata or spores. The 

 hymenium therefore presents the appearance of having been de- 

 veloped quite normally up to a certain stage, and of then having 

 had its development arrested. 



Cystidia develop in the sterile fruit-bodies in the normal manner, 



FIG. 21. Some sterile fruit-bodies of Coprinus lagopus (= C. fimetarius) grown 

 on sterilised horse dung in the laboratory. The pilei were yellowish -white, 

 owing to the gills being white on account of the absence of spores, and owing 

 to the presence of a yellowish-brown pigment in the pileus-flesh toward the 

 apex. The expanding fruit-body lying horizontally in the foreground should 

 be contrasted with the left-hand fruit-body of Fig. 20. Natural size. 



i.e. they grow to the normal size, acquire the normal shape and, 

 before the expansion of the pileus, are firmly attached to both of 

 the opposing gills, so that they form a series of bridges across the 

 interlamellar spaces (Fig. 22, C). Cystidia, in normal fruit-bodies 

 of Coprini, always develop very early and attain full size before the 

 basidia give birth to spores. Since the basidia of our sterile fruit- 

 bodies do not have their development arrested until the moment 



