REVISIONS OF CEYLON FUNGT. 287 



During investigations into the above-mentioned root 

 disease, numbers of examples of Ustulina have been grown in 

 the laboratory, and their development carefully watched. 

 Because of its polymorphic character, it was intended to write 

 a special account of this species with illustrations of its various 

 forms, but as the prospect of doing that becomes yearly 

 more remote, the following note must suffice. 



The mycelium of the fungus runs between the wood and 

 the cortex in white fan-shaped patches which often acquire a 

 black edge. When about to produce the fructification it 

 bursts through the cortex, forming a white pustule only two 

 or three milhmetres in diameter. Its subsequent growth 

 varies, probably according to external conditions. 



In producing the form which is most widely different from 

 Ustulina vulgaris, the white hyphse spread out over the surface 

 of the host and form a thin, resupinate, more or less circular 

 plate, attached only at the centre. It is this form in which 

 the zones, which represent stoppages in growth, are most 

 clearly developed. This occurs on tea, and is the commonest 

 form on coconut. I have observed plates, 9*5 cm. long and 

 4 cm. broad, only 3 mm. thick in the centre. 



In other cases, the hyphae on emerging from the cortex 

 grow out in an upright column, which expands into a flat- 

 topped turbinate structure, sporiferous on its upper surface 

 only. I have measured such, l-o cm. high and 1 cm. 

 diameter across the top. These have the appearance of a 

 Poronia, or, when several such structures arise close together, 

 of Kretzschmeria . But frequently . when several arise near one 

 another, the discs fuse together, so that the ultimate production 

 is a flat plate supported at several points ; or when the fusion 

 is incomplete the appearance is that of Moller's Hypoxylon 

 symphyton ; the latter exactly resembles, macroscopically, 

 some forms of our Ustulina, but its spores are much smaller. 



Finally, there is a form which is indistinguishable from the 

 European species. This is specially found when the fructifica- 

 tion develops on the host plant at the collar and on the 

 surrounding soil. In such situations the plates are curved and 

 convoluted, fused to each other in all manner of ways, and 

 forming irregular crusts, sometimes a foot or more in breadth. 

 6(3)12 (37) 



