484 THE SOOTY MOULD OF CITRUS TREES, 



infested with scale, but very little of the " sooty mould." There 

 was also upon the scale a considerable quantit}"^ of a parasitic 

 fungus known as Microcera coccophila, Desm. 



In some cases on the upper surface of the leaf there was a very 

 thin stratum of a mud colour, of just sufficient consistency to 

 hold together when peeled off, but no more. It was evidently 

 largely composed of fine dust, and scattered over it were little 

 dark punctiform bodies, ver}' variable in size when looked at with a 

 magnifying glass. 



Under the microscope it was seen to consist of a network of 

 colourless hyphae, and numbers of the spherical or irregularly 

 shaped bodies we have already called glomeruli. 



There were very few traces of the greenish-brown hyphse 

 developed, as the dust had evidently kept the fungus in check. 



The colourless or very pale green hyphaj were closely septate, 

 copiously branched and densely crowded so as to form a pavement 

 of cells. The hyph?e were either moniliform or with longer 

 or shorter joints, and bore various gonidia. Tho diameter of 

 the hyphse varied considerably, but the l^roadest was from 6-7^^ /n, 

 and narrowest about 4 fi. 



The glomeruli were exceedingly numerous, scattered or in 

 clumps, and were yellowish-green to pallid or even brownish. 

 They varied considerably in shape from spherical to hemispherical 

 or o^■al, and in size some measuring 250 /li or ^ mm. in diameter. 

 The mulberry-like green clusters and the contents were similar to 

 those already described. 



No other reproductive bodies were found. 



Even in cases where to the naked eye there is nothing but a 

 patch of dust on the leaf, there are the colourless hyphte forming 

 a close network of cells, and their gelatinous coating causes the 

 dust to adhei-e. 



As the result of the examination of a large number of specimens 

 I find that the colourless filaments are the earliest formed, 

 branching and intertwining so as to form a close network, adherent 

 to the surface of the leaf. 



