364 



RESEARCHES ON FUNGI 



marked characteristic of the mature pileus. In a very young 

 primordium there is no evidence of a differentiation into stipe and 

 pileus : the inner mass of hyphae surrounded by the universal veil 

 appears to be homogeneous, just as in Psalliota camjyestris . As a 

 primordium becomes somewhat larger and older, and before there 

 is any evidence of an external annular fitiTow differentiating pileus 

 and stipe from one another from without, stained longitudinal 



sections exhibit, near 

 the upper end of the 

 young fruit-body and 

 some distance in from 

 the surface, two small 

 deeply stained areas. 

 These are really part 

 of an annular area 

 within the fruit-body, 

 which is composed of 

 hyphae which are 

 densely compacted 

 and rich in proto- 

 plasm. These hyphae 

 make up the primor- 

 dium of the gills 

 (Fig. 183). It is to be 

 noted, therefore, that 

 the primordium of the 

 gills arises as in Psalliota campestris,^ i.e. that it comes into existence 

 internally at a time when the fruit-body is homogeneous and com- 

 pact except for the looser envelope. After the primordium of the 

 gills has come into existence, interlamellar spaces arise within it, 

 and the plates of tissue thus separated from one another develop 

 into the gills (Fig. 184 and in Vol. Ill, Fig. 140, p. 318). A gill- 

 chamber apart from these interlamellar spaces was not observed. 

 The gills in their youngest stage have their long axes directed 

 perpendicularly to the long axis of the carpophore (Fig. 183) ; but, 

 with further growth, they become obliquely situated, their inner 



1 Cf. G. F. Atkinson, he. cit., p. 249. 



Fig. 183. — Copriniis imtcrorhizus. A median-vertical 

 section of a very young fruit-body with its hymeno- 

 phore just becoming differentiated. As yet no 

 pseudorhiza has been developed. Magnifi- 

 cation, 46. 



