1 6 RESEARCHES ON FUNGI 



essential function of producing spores. Instances of sterility of this 

 kind have been noticed in two different species. A board was found 

 in a cellar infected with Coprinus fimetarius, var. cinereus, and a 

 small piece of it, bearing a young fruit-body, was sawn off, brought 

 to the laboratory, and placed in a damp-chamber. After further 

 development the fruit-body attained average size and form, but 

 exhibited the peculiarity of being yellowish-white in colour instead 

 of ashy grey. Upon examining the pileus with the microscope, I 

 found that it was almost completely sterile. Only a few basidia had 

 produced spores, whilst the great majority had remained in a rudi- 

 mentary condition. The normal basidia were found chiefly at the 

 pileus margin, but a very few were sparsely scattered over the 

 general surfaces of the gills. Two other fruit-bodies subsequently 

 appeared on the piece of board, but in these the spores were 

 developed in the usual manner. Coprinus plicatiloides 1 was grown 

 on sterilised horse-dung, from the surface of which its fruit-bodies 

 were produced in large numbers, several each day for more than a 

 month. At successive intervals about six fruit-bodies came up, 

 which seemed to be quite normal in size and form, but which were 

 conspicuous among their companions by being whitish-yellow instead 

 of grey. The microscope revealed the fact that the gills had failed 

 to produce any spores. The basidia, surrounded by large paraphyses, 

 had remained quite small ; they did not protrude beyond the general 

 surface of the hymenium and, so far as I could observe, they had not 

 even given rise to sterigmata. 



The cause of the occasional sterility of Coprinus fruit-bodies seems 

 to be somewhat obscure. Since, however, the sterile fruit-bodies of 

 Coprinus plicatiloides grew in company with, and closely adjacent 

 to, other fruit-bodies which were completely fertile, it seems safe to 

 infer that the sterility was not conditioned by temperature, light, 

 heat, moisture, or atmospheric gases. Perhaps the phenomenon is 

 due to some accident happening to the mycelium at the time when 

 its contents are being poured into the young fruit-body. It is con- 

 ceivable that, if the mycelium attached to the fruit-body were 

 reduced in quantity, the fruit-body might suffer from starvation 

 during its further development, and yet, in consequence of the 

 1 For nomenclature of this species, vide infra, Chap. IV. 



