251 



• 





r 



lengths for propagation and inserted, in order to see to what 

 extent silvering may be transmitted by vegetative propagation. 



The discoloration in the wood was very slight and could only 

 be seen with a pocket lens; it was traced for a distance of 18 cms. 

 up the silvered sucker. 



Text jig. 5. — Longitudinal section 

 of root of Neviusia alabaniensis. 



Text fig. 6. — Longitudinal section 

 of a shoot of Neviusia alabaynensis, 





:■ 



The hyphae were followed to within 2 cm. of the upper limit 

 of the discoloured wood. In the silvered branches the inner 

 wood elements are stained pink, passing over to bluish magenta 

 towards the cambial region, whereas the cavities of the phloem 

 and medullary rays cells are filled with a dark brown mass. 

 Yeiy few hyphae were seen in the central wood elements, but 

 abundant threads were present in the elements bordering the 

 cambial region (see Text Fig. 7). It was difficult to cut entire 

 hand sections, as the xylem invariably separated from the bast; 

 the cambial cells showed localised disorganisation as a result of 

 the invading hyphae; the bast parenchyma also was somewhat 

 affected and easily broke up, but no hyphae were observed in it. 



The leaves were not examined and no fructifications of 

 Stereum purpureum were noted anywhere on this partially 

 silvered plant, but the characters of the hyphae were identical 

 with those of other hosts, and those of mycelium grown in arti- 





ficial cultures. 



Whether shoot as well as root infection took 



place in this plant cannot definitely be stated, but since browning 

 could be traced from the root-stock into the lower part of the 

 sucker only, it is certain that in this case the fungus gained 

 entry through the injured root-stock. 



# 15 cuttings were inserted in a cold frame in the Royal Botanic Gardens 

 Kew, all of which have produced silvered shoots. 



