THE PSEUDORHIZA OF COPRINUS MACRORHIZUS 365 



edges remaining in contact with, and in continuity with, the 

 primordium of the stipe (Fig. 184). 



With the differentiation of the primordium of the gills, the other 

 parts of the young fruit-body become 

 delimited. We can now distinguish 

 the primordium of the pileus-flesh 

 and the primordium of the stipe. 

 The universal veil at this stage is 

 seen to form a continuous layer 

 which encloses both pileus and stipe 

 (Fig. 184). Soon after the young 

 gills have begun to grow downwards, 

 a very slight annular furrow makes 

 its appearance on the outside of 

 the whole fruit-body (Fig. 181, B-D, 

 p. 361). This furrow, which becomes 

 more and more pronounced as the 

 gills grow in size (Fig. 181, G-J), 

 marks off the pileus which lies above 

 it. 



The annular furrow, just referred 

 to, may be considered as dividing 

 the stipe into two parts, an upper 

 interpilear part which is enclosed 

 between the gills, and a lower sub- 

 pilear part which is entirely below 

 the gills. These two parts are con- 

 tinuous with each other ; but, as we 

 shall see, it is convenient to dis- 

 tinguish between them. 



If a fruit-body develops directly 

 on the surface of the substratum, 

 as sometimes happens in nature 

 (Fig. 182, p. 362) and in artificial 

 cultures, the primordium of the 



stipe as a whole becomes differentiated into two parts. The 

 interpilear part becomes the primordium of the shaft of the 



Fig. 184. — Coprinus macrorhizus. 

 A median-vertical section 

 through the upper part of a 

 slender cylindrical fruit-body 

 which was pushing its way 

 upwards through manure (c/. 

 Fig. 181, B and C ; also Fig. 186, 

 h and c). The pseudorhiza is 

 pushing up the rudimentary 

 apical pileus by elongating in an 

 intercalar J' zone of growth which 

 is just below the level of the 

 base of the gills. At this stage 

 of development, the universal 

 veil covering the apex of the 

 fruit-body is compact and func- 

 tions like a root-cap. Magnifi- 

 cation, 19. 



