no 



RESEARCHES ON FUNGI 



been formed in dimly-lighted clefts of two of the balls continued 

 their development and grew up into normal spore-producing fruit- 

 bodies. 



From the experiments just described it seems safe to conclude 

 that daylight, whilst not able entirely to prevent the formation of 

 fruit-body rudiments of Coprinus sterquilinus in the first place, 

 inhibits the further growth of the rudiments at a very early stage of 



Fig. 62. — Coprinus sterquilinus. Another aspect of Culture C, grown in complete 

 darkness. Fruit-body rudiments can be seen on the top of the horse dung, 

 and from three such rudiments three perfect fruit-bodies are developing. Here 

 again, owing to the absence of light, the solid stipe-bases are well developed and 

 project up above the surface of the dung, while the pilei which cap them have 

 remained up to the present relatively small. Photographed 20 days after the 

 culture was started from mycelium. Natural size. 



their development. It must be pointed out, however, that light 

 has an inhibitory action only upon very small rudiments, i.e. those 

 having a diameter not exceeding about 1 mm. A rudiment which 

 has originated in the dark and has attained a length of about 3 mm. 

 is no longer checked in its further growth when exposed to hght, 

 but can develop into a normal fruit-body. In top-Ughted cultures, 

 such as Culture A, as we have seen, the upper lighted rudiments all 

 become aborted, and the mature fruit-bodies all arise from rudiments 

 which have come into existence on the darkened lower sides of 

 the dung-balls. The successful rudiments, although arising in the 

 dark, soon push their way upwards into the light ; but, by the 



