OMPHALIA FLAVIDA 429 



to very dry air seriously injures the gemmae within 0- 5-1-0 hour 

 and kills them within 26 hours. 



Some gemmae were removed from their pedicels and set on a 

 cover-glass in a Petri dish in which the air was saturated with water 

 vapour for 24 hours and, at the end of this time, they were placed 

 in a hanging drop of malt-agar. They germinated perfectly. From 

 this we may conclude that gemmae, after being blown from their 

 pedicels on to other leaves in a Coffee plantation when the weather 



Fig. 218. — A leaf of Bryophyllum calycinum infected with the myceliiun of 

 Omphalia flavida which, in the course of about a month, produced gemmifers 

 first and then, as here shown, a number of perfect fruit-bodies. The leaf 

 was isolated, inoculated with gemmae, and kept moist on wet sand. The 

 fungus has killed most of the leaf which, however, has succeeded in pro- 

 ducing a few new shoots and roots at its edge. Natural size. 



is moist, probably retain their vitality and ability to germinate for 

 several days. 



Inoculation Experiments with Living Leaves. — In 1901, Kohl 1 

 examined many hundreds of Coffee leaf-spots and observed that 

 there was a gemma adhering to the epidermis above the middle of 

 every one of them. With a little practice and under favourable 

 light conditions, he succeeded in finding the gemmae even with the 

 naked eye. Thus Kohl obtained strong evidence that, under natural 

 conditions, Omphalia flavida is propagated by its gemmae. In 

 80-85 per cent, of the leaf-spots examined the gemmae were attached 

 to the upper side of the leaf, while in the remaining 15-20 per cent, 

 they were attached to the lower side of the leaf. 



Kohl 2 also carried out some inoculation experiments. He 

 1 F. G. Kohl, loc. cit., p. 63. 2 /{,j^,^ pp. 64-65. 



