COPRINUS MICACEUS 



343 



the general level of the hymenium, i.e. above the paraphyses. The 

 four sets of spores which are really present in Fig. 153 at A, are 

 shown differentiated from one another by shading in the same 

 Figure at B. Everywhere in each set the spores occur in quartettes, 

 and each quartette corresponds to a subjacent basidium. The 

 four sets of spores, as developmental studies show, belong to four 

 generations of basidia. The basidia of the first generation have 

 the longest and most protuberant bodies ; the basidia of the second 



Fig. 153. — Coprinus micaceus. Camera-lucida sketches showing positions 

 of the spores on the surface of a small area of the hymenium. A, the 

 spores all represented as being in the same plane, to show crowding 

 and overlapping. B, the same set of spores analysed according to 

 generations ; a, (shown black), 6, (cross-hatched), c, (shaded with lines), 

 and d, (unshaded) are the spores of the basidia of the first, second, third, 

 and fourth generations respectively. Spores of an older-generation 

 basidium often stand partly over those of younger-generation basidia. 

 Magnification, 293. 



generation have somewhat shorter and less protuberant bodies ; the 

 basidia of the third generation have still shorter and still less pro- 

 tuberant bodies ; while the basidia of the fourth generation have 

 bodies which are the shortest of all and practically non-protuberant. 

 The differential protuberancy of the four generations of basidia will 

 be at once realised by a glance at Fig. 156 (p. 348), which represents 

 the hymenium in cross-section. It is clear that the basidia are 

 tetramorphic and that the bodies of the basidia of the first genera- 

 tion are a little more than twice as long as those of the basidia of 

 the fourth generation. As shown in Fig. 156, the spores do not 

 vary in size according to the length of the basidia upon which they 

 arise ; for those on the shortest basidia are just as large as those 

 on the longest basidia. 



