284 RESEARCHES ON FUNGI 



or three layers of cells which are oval or rounded in shape and some- 

 what irregularly disposed ; and the relatively broad trama, tr, the 

 elements of which are more or less cylindrical in form, in general 

 elongated in a direction perpendicular to the pileus-flesh and parallel 

 to the hymenial layers, and often anastomosing with one another. 



On the left-hand side of the Figure, the section is represented as 

 passing through : a white area of the hymenium, A ; a black area, 

 B ; a brown area, C ; and another white area, D ; and on the right- 

 hand side as passing through a black area, E ; a white area, F ; 

 a brown area, G ; and another black area, H. These black, brown, 

 and white areas correspond to similarly coloured areas which have 

 already been described in surface view and which are shown in 

 Figs. 89 and 90 (pp. 257 and 258). 



It was pointed out that a study of adjacent areas of the hymenium 

 of a gill of Panaeolus campanulatus, seen in surface view, leads to the 

 conclusion that the hymenium is so organised that its development 

 takes place in a series of waves of small dimensions which move 

 irregularly and simultaneously through it x ; and by means of camera- 

 lucida drawings, reproduced in Figs. 89 and 90 (pp. 257 and 258), 

 the direction of the waves on two small areas was clearly shown. 

 Now in transverse sections through the hymenium the wave mode 

 of hymenial development can also be made out. It has therefore 

 been indicated iii Fig. 96 by means of an appropriate arrangement 

 of the elements. 



A wave of development in the hymenium on the left-hand 

 side of Fig. 96 is represented as passing from above downwards. 

 The basidia opposite the Roman numerals, I, II, III . . . XII 

 developed their spores in succession. The basidia I and II shed 

 their spores an hour or two ago and have collapsed. The basidium 

 III shed its spores about 15 minutes ago and is hi the act of 

 collapsing : the sterigmata are being drawn into the concavity which 

 is forming at the end of the basidium-body. The basidium IV 

 is discharging its spores : two of them have already been shot 

 away, and the lower one of the remaining two should be shot 

 away at the end of about one second, for the drop of fluid excreted 

 at its hilum has just attained its full normal size and is about 

 1 Vide supra, pp. 258-259. 



