Fungim of Lolium. 259 



transverse section nearer the proximal end of the grain, as is- 

 shown in Fig. 2, would cut- through the scutelluni. Such a section 

 shows that the hyphae occur Ijetween the endosperiu and the scutel- 

 luni wherever the tissues are in contact, and hyphal 2^t?iit?trations 

 into the scutelluni may and do take place at any point over this 

 area. Tlie hyphae in addition extend even past the limits of the 

 aleurone layer, and penetrate the scutelluni on its outer exposed 

 dorsal surface. A transverse section at the extreme proximal end 

 of the grain. Fig. -S, passes through the embryo, l)Ut the starchy 

 endosperm is no longer included in the section. Even at this level 

 the hyphae surround the scutelluni, as is indicated by the yellow 

 line in tlie Hgure. The coronal plane is perhaps the best for demon- 

 strating the distribution of the fungus in any one section (Plate 

 XVIII. Fig. 4), the occurrence of the fungal layer between the 

 scutelluni and endosperm at all points of contact and the extension 

 of the fungal tissue on the dorsal proximal surface is clearly seen. 



Plate XVIII. Fig. 5, shows a median sagittal section illustrating 

 the same points and, in addition both of these latter sections shew 

 the distriltution of the hyphae in the embryonic area. The scutellum 

 is often very richly traversed by tine fungal threads, and they are 

 not restricted to any special area, but occur more or less uniformly 

 right through the tissue. Some grains show these threads more 

 readily than others, but a study of the embryology of the grain 

 will suggest that this might often be the case. Ihe hyphae are 

 readily discernil)le in the growing cone; their presence here has 

 been pointed out by the earlier workers. (Text-figure 1.). The 

 alx)ve facts are also true of Lohuin tenudentuin, but it is much 

 rarer in this case to obtain a scutellum so markedly inliabited as 

 in Loliiiiu pcrenne, and in any case the threads are generally finer. 

 In several examples of Lolium iierenne I have found hyphae present 

 in tlie railicle, but they are not generally evident in this region. 



Freeman raises the question — How does the fungus obtain en- 

 trance to the embryo? As an answer, he devoted a large part of 

 his paper to a description of a localised patch of liyphae, which he 

 termed " ihe infection layer-,''' and to its mode of origin. He says 

 that on the ventral proximal end of the grain there occurs an iso- 

 lated patch of hyphae which penetrates between the aleurone cells? 

 and cells of the scutellum, and tliereby gain entrance to the 

 embryo when it is fairly advanced in its development. He 

 states that- on the dorsal surface of tlie grain the hyjahae 

 do not extend to the end of the aleurone layer. To 



14 



