428 



RESEARCHES ON FUNGI 



were exposed to the air of the laboratorj^ for half an hour, one hour, 

 and 26 hours respectively, after which they were treated in the same 

 manner as the gemmae on cover-glass A. The air in the laboratory 

 was remarkably dry and the gemmae on the cover-glasses B, C, and 

 D, when exposed to it, dried up within about a minute. Whilst 



undergoing desiccation, 

 the gemmae became 

 much shrunken. When 

 treated with water, 

 they rapidly expanded, 

 and their expansion 

 was doubtless due in 

 part to the imbibition 

 of water by the gela- 

 tinous matrix in which 

 all the cells of each 

 gemma are embedded. 

 After the gemmae 

 had been 24 hours in 

 malt-agar , it was found : 

 (1) that the gemmae 

 on the cover-glass A, 

 which had not been 

 allowed to dry up, 

 had all germinated 

 perfectly, their infec- 

 tion hyphae having 

 grown out radially from 

 the gemma to a dis- 

 tance equal to the 

 gemma's diameter ; (2) that the gemmae on the cover-glasses 

 B and C, which had been dried for half an hour and one hour 

 respectively, had germinated imperfectly, for only very few of the 

 infection hyphae of each gemma had grown out radially into the 

 culture medium ; and (3) that the gemmae on the cover-glass D, 

 which had been dried for 26 hours, had not germinated at all. 



From the above series of experiments it is obvious that exposure 



Fig 



217. — Omphalia flavida on a leaf of Bryo- 

 phyllum calycinum, two weeks after inocula- 

 tion. The leaf was wounded by lightly 

 scratching it in the centre and also near the 

 left lower edge ; and then a few gemmae were 

 sown on the wounds. The mycelium grew 

 into the leaf-tissues and formed two leaf -spots. 

 In the central leaf -spot can be seen a number 

 of gemmifers each bearing terminally a tiny 

 gemma. Natural size. 



