﻿iqi6] ATKINSON-COPRINUS 12,3 



to arise in a centrifugal direction, following up the progressive 

 development in the same direction of the palisade hymenophore, 

 cavity, and pileus margin. The salients are formed by increase 

 and enlargement of the elements of the palisade layer along these 

 radial areas and by the downward growth of the subadjacent 

 trama cells of the pileus. The lamellae increase in width by 

 apical and also by intercalary growth. 



5. The attachment of the gill margins to the stem takes 

 place after the origin of the gills. It begins when the gill margins 

 come in contact with the stem, or the fundamental plectenchyma 

 surrounding the stem. The age and breadth of the lamellae when 

 the attachment begins varies in the different species and in different 

 individuals, according to the strength of the general gill cavity and 

 the proximity of the gill to the margin of the nearly mature pileus, 

 where the space may be more cramped. 



In Coprinus comatus the lamellae may become cfuite broad before 

 they begin their attachment, except at the extreme margin of 

 the pileus. Before they begin to form the attachment with the 

 stem, the palisade layer is continuous over the margin, the palisade 

 cells here not being differentiated from those on the sides. After 

 they have been in contact with the stem surface for some time 

 many of the marginal cells are spread laterally by the pressure. 

 Others, together with short hypha from the end of the trama, inter- 

 lace lightly with the open meshed plectenchyma on the surface 

 of the stem. 



In Coprinus atramentarius, since the general gill cavity is weak, 

 the young salients, as well as the intervening spaces, are connected 

 here and there by isolated hyphae, or loose hyphal strands which 

 were not ruptured during the tearing apart of the fundamental 

 plectenchyma below the young hymenophore palisade. The 

 palisade layer extends over the margin of the young salients. As 

 the lamellae broaden, the margins press against and into the loose 

 ragged surface of the fundamental plectenchyma on the surface of 

 the stem. Short slender threads from the margins grow outward 

 and interlock with this fundamental plectenchyma. As the pres- 

 sure becomes greater, many of the palisade cells are pressed later- 

 ally so that there is a partial connection of the trama ends with 



