Fungus of Lollmn. 2 60 



.as many as three cells. As is well known, the cell walls of this 

 layer are thick, and also pitted. The hy^shae enter through these 

 j)its, and thereby gain access to the cell (Plate XIX. Fig 5). Sonie- 

 tinies the opening in the M'all of the aleurone cell was smaller in 

 diameter than the penetrating hypha ; when this was the case a 

 conspicuous narrowing was noticed at the point of entrance, but 

 on the far .side of the pit the hypha again attained its previous size. 

 In addition the scutellum showed an extraordinarily large amount 

 of tlie fungus. Here the intra-cellular course was also verv evi- 

 dent (Plate XIX. Fig. 4). Many of the scutellar cells stained 

 vividly; such cells were seen to be fungal containing. The entrance 

 to the cells was gained through jjitted walls, as is the case in the 

 .aleurone layer. The remaining cells of the scutellum Avere normal, 

 and the grains did not seem to be any the worse for tliis excep- 

 tiimal behaviour on the part of the fungus. In such abnormal 

 grains the hyphal layer was present as usiial. There is no doubt 

 that the hypliae invading tlie cells are the same as those composing 

 the extra cellular layer. 



These phenomena were not confined to the sample from Ireland, 

 one of English rye grass from Soutli Africa also contained certain 

 grains showing an extraordinary distribution and growth of the 

 fungus. As before, both the aleurone layer and the scutellum were 

 permeated by intra-cellular hyphae. In one jjarticular case +he 

 scutellum, which normally is packed with aleurone grains, appeared 

 to consist of a dense sclerotial-like mass of threads. The ])ulk 

 remained colourless, and they resembled " ghosts," or casts, of 

 former more virile hyphae (Text figure 2). They are represented 

 in the text figure as dotted lines, and they completely filled the 

 whole of the scutellar tissue, although the cells composing it were 

 not distorted or enlarged in any way. lliis section cut in the 

 coronal plane) and the others accompanying it, wei'e later stained 

 witli Congo red; it was then easier to decipher the.se ghost-like 

 contents of the scutellum. Many were cut transversely, but owing 

 to a large amount of twisting some were seen running lengthwise 

 through the tissue for a short distance. They probably represent 

 fungal hyphae, which were numerous at certain stages in the 

 development of the grain, carrying a, special food supply to special 

 ■parts, and in giving this up to the host-plant theyhave undergone 

 a partial dissolution, which was not completely carried out in 

 "these few excejDtional cases by the time the grain reached maturity. 



