Chlamydosfiore-Formation in a Basidiomycete. 19 
Plate cultures (Gelatine and Grape Extract) were also made of 
the spores and a mass of characteristic soft, flocculent white 
mycelium was eventually produced which bore innumerable spores 
of the type already described. 
Another set of sterilised Elm-blocks was also infected with 
small pieces of mycelium from the originally infected blocks ; this 
mycelium spread rapidly and in turn produced the typical spores in 
great quantities. In no case was any trace of the regular hymenial 
fructification observed. 
The cultures were kept under observation for some months, 
blocks being fixed at intervals for microscopic investigation. After 
the first two months, however, the mycelium did not appear to be 
spreading over the blocks very rapidly, though it often collected into 
little clots, especially at the summit of the blocks, in some cases 
making its way up in strings as far as the cotton-wool plugs which 
closed the mouths of the tubes in which the blocks were placed. 
On cutting sections of the blocks at different stages of the 
infection, it was found that the fungus appeared to have only a very 
slightly destructive action on the wood. For although a number of 
hyphas were found to have penetrated into the vessels of the wood, 
after more than five months the medullary rays appeared practically 
untouched, though, as seen on staining with Schulze’s solution, they 
were exceptionally full of starch, etc. 
Yet in artificial block-cultures of such a fungus as Stereum, 
Marshall Ward 1 found that the medullary rays were almost the 
first elements to be attacked, and after some four months were 
completely invaded and their contents destroyed, by the hyphae. 
Further, in Stereum the hyphae are described and figured as passing 
radially from one tracheid to another through the pits in all 
directions, whilst in Pleurotus subpcilmatus this is only comparatively 
rarely to be observed. 
The hyphae appear to pass into the larger vessels of the wood 
in considerable numbers, and then to make no further headway, but 
what is interesting is the fact that they there produce large numbers 
of chlamydospores, though it is difficult to see of what particular 
advantage this can be to the fungus (Text-fig. 1). Very good 
preparations were obtained by staining with Delafield’s Haematoxylin. 
The original object of this investigation was, by using double 
stains, etc., to endeavour to obtain more evidence as to the 
destructive effect of the hyphae upon the lignified cell-walls. For 
1 Phil. Trans., Series B, 1897, Vol. 189, p. 123. 
