250 



of it had already been killed. On splitting the shoot so as to 

 expose the pith, it was noticed that the discoloration was found 

 throughout the wood but it was most marked towards the pith. 







Text fid. 4.— Longitudinal section of Spiraea japonica var. glahrata, 



showing hyphae in the wood. 







The discoloration could be traced upwards to a point 90 cm. 

 above the root stock, but the last 20 cm. of the shoot displayed 

 no discoloration. Three other silvered shoots were cut oft' above 

 ground, measuring from their point of last year's pruning, 140, 

 135, and 150 cms. respectively; curiously enough on splittin 

 these shoots the discoloration was found to be absent from the 

 base upwards to a height of 40, 45, and 63 cms. respectively; the 

 browning then gradually increased in an upward direction 

 towards last year's point of pruning. The absence of discolora- 

 tion at the base of these three shoots suggests that the fungus had 

 entered through the wounds caused by pruning. 



The nature of the discoloration of infected material varies 

 within the tissues and according to the host. In the roots of 

 Neuiusia the discoloured cells assume various colours, from a 

 purplish red to magenta, seldom a reddish brown (see Text 

 Fig. 6). In the stem, the purple and magenta colour are re- 

 placed by a reddish pink, passing over to a dark brown. 

 Abundant hyphae were present in the wood generally, but they 

 were predominant in the xyleua elements bordering the pith. 

 (Text Fig. 6.) This is probably owing to the fact that there is 

 greater aeration in the pith region. No hyphae were noticed 

 eyond the discoloration, which ^proves that the fungus has 

 penetrated in the one case through the injured root stock, and 

 in the other three cases as a result of pruning. 



(7) R 



cereuni. — "While 



examining 



the bed of 

 my 



Portugal 



Laurel in 3vew Garden 



drawn to a plant of Ribes cereum growing about 2G ft. distant. 

 On a single shrub four branches of the current year's growth 

 exhibited silvering; one of these, a sucker, was taken to the 



laboratory 



The 



remaining 



three shoots had developed at 



different heights from the ground; they were cut up into suitable 



