BOLBITIUS FLAVIDUS 



73 



The black circles represent the positions of the basidia of the first 

 generation to produce spores, the cross-hatched circles the positions 

 of the second-generation basidia, the circles shaded with lines the 

 positions of the third-generation basidia, and the unshaded circles 

 the positions of the fourth-generation basidia. The actual arrange- 

 ment of the basidia in one small area of the hymenium is shown in 

 Fig. 36, B, where the tendency to form the pattern given in the 

 diagram can undoubtedly be recognised. The drawing was made 



6-, 



'~W-6<*d^>-' 





B 



Fig. 36. — Bolbitius flavidus. A, a diagram showing a regular arrangement 

 of the elements of the hymenium, the basidia appearing as circles and the 

 paraphyses, p, as squares. There are four successive generations of 

 basidia, a, b, c and d, each generation represented by nine basidia. The 

 basidia a (black) belong to the first generation, b (cross-hatched) to the 

 second generation, c (shaded with lines) to the third generation, and d 

 (plain) to the fourth generation. B, a camera-lucida drawing of an actual 

 hymenium showing an almost regular arrangement corresponding to that 

 of A. The first -generation basidia, a, have shed their spores. The 

 second- generation basidia, b, are now bearing spores. The third- and 

 fourth-generation basidia, c and d, cannot at present be distinguished 

 from one another, p, the paraphyses. Magnification, 345. 



at the time when the second generation of basidia was ripening its 

 spores, and this generation could easily be distinguished by their 

 presence. It is noteworthy that even the groups of four spores 

 exhibit a distinct tendency to orient themselves in one definite 

 manner, and not according to the laws of chance. The first- 

 generation basidia, a, are represented by the collapsed basidia which 

 have already shed their spores and which are about equal in number 

 to those of the second generation, b. The third-generation and 

 fourth-generation basidia, c and d, are represented by young basidia 



