﻿igi6] A TKINSON—COPRINUS 1 1 9 



so very different from that presented by what I have spoken of as 

 the Agaricus type. The trama of the gills suggests that the primor- 

 dial trabeculae, which have thus far been the earliest observed 

 structures, in the differentiation of the hymenophore, may originate 

 as parallel, closely approximated thin areas of hyphal growth which 

 remain very closely side by side until the sharper differentiation in 

 the hymenophore appears with the formation of the palisade layers. 



The primary and secondary lamellae are free through- 

 out THEIR DEVELOPMENT, UNDER NORMAL CONDITIONS.— If in the 



origin of the lamellae they were preceded by a series of isolated 

 radial ridges with intervening areas of fundamental elements, the 

 fundamental plectenchyma, or elements, would be continuous 

 around these isolated ridges. Then in the later formation of the 

 lamellae, by the splitting and parting of these ridges, tangential 

 sections parallel with the axis of the stem would show the "trama" 

 of the forming secondary lamellae continuous with that of the 

 adjacent primary lamellae, as well as with the stem, until a stage of 

 development was reached in which these connections were torn 

 free. Such a condition is never found in normally developed 

 plants. The secondary lamellae are free from the primary ones in 

 all stages of development where the lamellae are normal. It not 

 infrequently happens that the tramae of two adjacent lamellae are 

 connected at or near the pileus, as when a secondary lamella sprouts 

 out from the side of the base of a slightly older lamella, as shown in 

 rig. 60, instead of sprouting out midway between two adjacent 

 lamellae. But in these cases, also, there is no communication 

 between the tramae of adjacent secondary and primary lamellae 

 through their margins, as there would be at certain stages of their 

 development if the lamellae originated as described by Leyixe. 



Attachment of the lamellae to the stem. — The attachment 

 of the lamellae to the stem in C. micaceus takes place in very much 

 the same manner as described for C. atramentarius. The variation 

 in details can be ascribed to specific differences. At the early 

 origin of the lamellae the margin of the salients in cross-sections 

 may be entirely free, or may be connected by isolated hyphae, or 

 loose strands, across the weak annular gill activity, with the funda- 

 mental plectenchyma below on the surface of the stem, as previously 



