BUTLER AND HAFIZ. 193 



cellular mycelium penetrate the walls to enter the cells. All the 

 tissues are invaded, bundles as well as parenchyma (PI. TV, Fig. 1). 

 In the cells, and especially in the vessels, veiy thick hyphse may 

 occur, sometimes almost alone, sometimes intermingled with the 

 fine filaments. Careful observation shows that both kinds belong 

 to the same mycelium and can be found in direct continuation 

 with one another. Sometimes a haustorium-like, branched mass, 

 arising from thick hyphtie in an intercellular space, almost fills a 

 cell. At first septation is rather scanty, but in the older hypha? 

 the septa lie verj' close together, the segments thus formed being 

 often broader than they are long. No trace of spore-formation 

 was found either in the tissues or on the surface of the diseased 

 canes before their death. 



Cultures of the fungfus were obtained in the usual way. 

 from the surface of the cane pith cut with a red-hot knife. The 

 fungus grew well on ordinary" nutrient agar, forming a dense 

 superficial growth. The following description is from pure 

 cultures on this medium. 



The mycelium is white or faintly tinged j^ellow. The 

 hyphre (PI. IV, Figs. 2 & 3) are very variable in size. The main 

 branches are very thick, sometimes up to 15// in diameter, at 

 first hyaline and sparingly septate, then pale yellowish and 

 closely septate. Branching is copious and often rectangula)-. 

 Very noticeable is the tendency of the older branches to give off 

 extremely fine, hyaline, thin-walled hyphse, the diflference in 

 diameter being so great as to suggest a distinct mycelium, until 

 carefully examined. The thin hynha} are often irreofularly 

 swollen or even nodular and measure sometimes as little as 1 /m in 

 diameter. Anastomosis of neighbouring branches is not uncom- 

 mon (PI. IV, Fig. 3a). Intermediate stages, consisting of hypha? 

 G to 8 fi in diameter, freely septate when old and often irregularly 

 swollen, are common. The thicker branches break up readily 

 into chlamydospores (PI. IV, Figs. 4 k 5), which may be termi- 

 nal or intercalar, and are usually arranged in short chains. 

 They consist of thick-walled cells filled with reserve material, 

 round, oblong or long elliptical in shape, variable in size, the 



