

1920] 



WALKER— CY A THUS 



7 



As the development of the peridioles progresses, the circle of 

 converging filaments enlarges, due to the multiplication of their 

 elements, largely at the sides, and a central space is observed. 

 This is well shown in figs. 26 and 28, which are higher magnifications 

 of the peridioles in upper and lower portions of the basidiocarp 

 seen in fig. 13. The central space is filled with slime, probably due 

 to the gelatinization of filaments of the fundamental tissue, which 

 are caught in the midst of the more actively growing converging 

 filaments, as in older peridioles remnants of such filaments are 

 clearly present (fig. 29). The cavity in the interior soon takes on 

 an oval or bean shape (figs. 15, 17, 23). This is due to the earlier 

 thickening of the walls of the peridioles on the upper and lower 

 parts, while the sides (ends) remain thinner. Growth remains 

 more active on the sides, and the addition of new elements here, 

 together with mutual pressure, determines the final shape. The 

 enlargement of the cavity in this way continues until the peridiole 

 has reached its mature size. 



The converging filaments lining the cavity are at first entirely 

 undifferentiated, appearing in every way similar to the ends of 

 actively growing vegetative filaments such as develop in culture 

 media (figs. 26, 28). Soon they begin to enlarge on the end, and 

 by the time the cavity has reached one-fourth to one-half its 

 ultimate size a definite palisade layer, composed of filaments 

 with enlarged ends, is formed (fig. 29). The palisade layer does 

 not have a uniform even surface as in most of Basidiomycetes, but 

 is made up of basidia and paraphyses of varying lengths. The 

 cells forming the palisade layer are binucleate at first, but the 

 nuclei soon fuse to form the primary nuclei of the basidia and 

 the uninucleate paraphyses (figs. 27, 31). At maturity the entire 

 cavity of the peridiole is densely filled with the oval, constantly 

 binucleate spores (fig. 32). 



For some time the walls of the peridioles remain only slightly 

 differentiated (figs. 13, 16). In the subhymenium large inter- 

 myceliar spaces remain, and to the outside of this is a denser 

 tissue which will develop into the thick inner wall of the peridiole. 

 Soon, however, the ground tissue of the gleba begins to gelatinize 

 in zones surrounding the already differentiated inner walls of the 





