Fuvgiis of Loliuin. 279 



Examination of such material reveak-d fungal hypliae occupying 

 the lumen of the aleurone cells, from which densely stained bodies 

 were budded off. Peklo lielieved them to l)e aleurone grains. It 

 seems highly probable that the grains used for sectioning were 

 mouldy, and that the aleurone grains figured are in the process of 

 digestion. Ihis is accentuated i)y the fact that some grains were 

 found actually embedded in the hyphae themselves, and also by the 

 fact that Peklo suggests that the fungal threads found l)ear a 

 resemblance to those of Mucor Rouxianus (Amylomyces JRou.rii)^ 

 although the actual identity of the two Avas not established. The 

 point of interest as far as this paper is concerned lies in the 

 fact that Peklo probably found the fungus in the aleurone cells of 

 young Loliuin temuleiiimn grains, and from this isolated case he 

 attempted to generalise, stating that such was the origin of the 

 layer for all cereals. 



The breadth of the hyphal layer found in the grain is dependent 

 on two factors — 



(a) The activity of the fungus, 



(b) The absorbing power of the endosperm. 



If the fungus is strong and luxuriant in its growth, and can keep 

 pace with the activity of the endosperm, a thick hyphal layer would 

 result, for even at maturity the endosperm will not have used, as 

 food-material for itself, all the available hyphae. 



If, however, the growth of the mycelium is inclined to l>e weak, 

 the absorbing power of the endosperm will be greater than the 

 growing power of the fungus, and the result will be a very small 

 layer in the mature grain, or even perhaps the complete absence of 

 such a layer. 



In the earlier part of this paper (p. 256) I cniphasise<l the fact 

 that absence of the fungus in hand-sections, or in any individual 

 microtome section could not be taken as evidence of the total absence 

 of the fungus in the grain. The reason for this statement should 

 now be clear. The presence or absence of a definite layer in the 

 grain is dependent on the activity of the fungus, and the absorb- 

 ing power of the endosperm. ?>en if a grain does not exhibit a 

 definite layer, hyphae may still be ])iesent in the embryo in sutlicient 

 amount to ensure the a])})earan(e of the fungus in (|uantity nt the 

 desired stage in the development of the next generation of Lulium. 



We are also in a position to discuss the significance of the dis- 

 tribution of the fungus in the grain. Freeman attributed it 

 mainlv to the i-esult of the niethod of infection of the eml)rvo, but I 



