152 RESEARCHES ON FUNGI 



moderate power of a microscope, one examines the side of a black 

 portion of a long gill of Coprinus comatus in face view, one's attention 

 is immediately attracted by the spores ; for these bodies are deep 

 black and stand out conspicuously on the white background pro- 

 vided by the general surface of the hymenium. A sketch of the 

 arrangement of the spores over a small area of the hymenium was 

 very carefully made with the help of a camera lucida and is repro- 

 duced as a plan in Fig. 60, A. The spores, at first, may seem to be 

 dotted about over the area in no particular order, as here illustrated ; 

 but, if one focusses up and down with the microscope, one soon 

 discovers that the spores are at two levels, a higher and a lower. 

 Half of the spores are situated on long basidia and the other half on 

 short basidia. The spores which are shown in Fig. 60 at A have 

 been re-sketched at B, so as to bring out the arrangement just 

 described. The spores on the long basidia are all represented in 

 uniform black, whilst those on the short basidia, for the sake of 

 distinction, have been shaded with Hnes. The black spores must 

 therefore be thought of as standing above the shaded ones. The 

 analysis can be carried further : the two sets of spores can be 

 re-sketched separately. In Fig. 60 at C are shown the spores which 

 are at the higher level in B, and at D are shown the spores which 

 are at the lower level in B, 



A glance at the cross-section of a gill represented in Fig. 63 

 (p. 160) will allow the reader to realise at once the relative heights 

 of the two sets of spores above the paraphyses. From develop- 

 mental studies which have been made for Coprinus sterquilinus 

 and which will be described in the next Chapter we are justified in 

 inferring : (1) that all the basidia which arise in the hymenium of 

 Coprinus comatus belong to two generations only, (2) that the 

 long basidia constitute the first or older generation and the short 

 the second or younger generation, (3) that the second generation of 

 basidia begins to develop spores shortly after the first generation 

 has begun to develop spores, (4) that the two generations therefore 

 overlap in their development and are not strictly successive to one 

 another, and (5) that each generation corresponds to a single genera- 

 tion of the Panaeolus Sub-type, such as one may see represented 

 by spores in the dark area in Volume II, Fig. 89, p. 257. Where 



