THE FUNGI 263 



sper media are very much smaller than any other form 

 of spore in the Uredinese, their average diameter being 

 about one two-hundredth of a millimetre. They are pro- 

 duced in great numbers and are accompanied by a 

 gelatinous substance which swells up when wetted, thus 

 pushing out the spermatia through the neck of the 

 flask. 



At present we are quite unable to say what these 

 spermatia are. They have been regarded as male cells, 

 perhaps serving for the fertilisation of the young d&cidium- 

 fruit, but at present there is no evidence for their sexual 

 function. Against it we have to set the fact that the 

 spermatia are capable of a sort of germination, though 

 they have never been known to produce a mycelium. 

 When cultivated in sugar and water they produce new 

 cells by " budding," each spermatium forming a little 

 branch which becomes detached from the mother-cell, 

 and repeats the process indefinitely. This is the same 

 mode of growth which is found in Yeast, the Fungus 

 causing the alcoholic fermentation of sugar. However, 

 the spermatia are certainly not identical with true 

 Yeast, and indeed the same mode of growth is common 

 enough among all sorts of Fungi. 



It is remarkable that the spermatia are accompanied 

 by a sugary secretion, which is sometimes so abundant 

 that a sweet flavour is perceptible if the surface of the 

 infected leaf be tasted. Further, these bodies often 

 have a pleasant, flower-like smell, and are observed to 

 be highly attractive to flies and other insects, which get 

 .smeared with the sticky masses of spermatia and help to 

 scatter them about. But until we have some idea of the 

 function of the spermatia, it is quite impossible to say 

 whether the insect-visitors are of any use to the Fungus. 



