iQig] WALKER— PLUTEUS AND TUB ARIA 15 



together with the expansion of the cells making up the pileus, similar 

 to that occurring in the blematogen, give the mature pileus the 

 furfuraceous appearance characteristic of the species. The detail 

 of the surface of the pileus at maturity is shown in fig. 93. 



ORIGIN OF MARGINAL OR PARTIAL VEIL 



In the early stages of the development of the pileus the blemato- 

 gen is the only distinguishable layer surrounding the fundaments 

 of the pileus and stipe, but by the time the pahsade layer has 

 developed (fig. 81) it can be seen that there are 2 distinct regions 

 in the portion of the veil extending between pileus , and stipe. 

 The inner region is made up largely of filaments that are continua- 

 tions of the more or less parallel filaments making up the margin 

 of the pileus that extend across and merge with those of the stipe, 

 while the outer portion is made up of the blematogen. As the 

 annular rift becomes increasingly larger these two regions show 

 more clearly (fig. 83). As the fruit body expands the blematogen 

 becomes stretched into a thinner layer, but the layers can be dis- 

 tinctly seen in fig. 87, where the gills are quite well developed. 

 During the expansion of the fruit body the partial veil ruptures 

 irregularly (figs. 74, 75), and being delicate soon disappears, so that 

 in the mature fruit body the veil is inconspicuous if seen at all. 



The development of the partial veil agrees entirely with that 

 described by Sawyer (17) for Pholiota, except that the veil quite 

 commonly ruptures near the stem instead of at the margin of the 

 pileus. Zeller's (19) illustrations of Stropharia also show a simi- 

 lar partial veil, but he does not describe its structure. 



Summary 



PLUTEUS ADMIRABILIS 



1. No entirely undifferentiated primordium of a basidiocarp 

 was obtained. The earhest stage secured showed a differentiation 

 into primordia of stipe, pileus, and hymenophore. 



2. All parts of the young basidiocarps are covered with free 

 ends of hyphae which lie more or less parallel to each other. The 

 primordium of the hymenophore is distinguishable by the smaller 

 cells composing it, with denser protoplasmic contents. It develops 



