F'tingus of Lolium. 293 



unlikely that tw<5 races of both Lolium temulentum and Lolium 

 perenne exist, one with a symbiont, the other fungus free. An occa- 

 sional grain of either species may show the absence of hypliae, but 

 tliis would be accidental in character, so that instead of an ever- 

 increasing, number of the latter type, they would always tend to 

 .remain at a more or less stationary minimum. 



Summary. 



The foregoing investigation has led to the following, results : — 



(1) The occurrence of the fungus in the genus Lolium is wider 



and more constant than has hitherto been demonstrated. 



(2) Colour of the grain cannot be regarded as a diagnostic 



character in regard to the presence or absence of tlie 

 fungus. 



(3) The fungus is intra-ct'llular or endophytic in nature. 



.(4) Ihe distribution in the grain is not a result of any special 

 method of infection, but is a result of the function of 

 the fungus during the grain's development. 



(5) It is present in the embryo-sac at or immediately after 

 fertilisation. 



;(6) Ihe fungus increases in quantity at the expense of the 

 nucellus, and the cells of the carpel wall. This is only 

 a temporary phase. . On the formation of endosperm 

 the fungus is absorbed as a source of food-supply to the 

 developing embryo. 



',(7) The endosperm is formed* by the division of its outer layer. 

 This layer functions as a kind of cambium. I have 

 termed it the endospermic camhium. The cells which 

 are cut off ahvays to the inner side, increase in size, re- 

 main thin-walled, and become packed Avith starch. This 

 outer meristematic layer is constantly receiving and 

 absorbing hyphae, which, if present in any quantitv, 

 are finally crushed into a layer around the periphery of 

 the endosperm. If the fungus does not keep pace with 

 the absorbing power of the endosperm, no hyphal layer 

 is formed in the ripe grain, but hyphae can then l>e 

 found in the scutellum and embryo. 



((8) The endospermic cambium after it has ceased to divide 

 persists as the aleurone layei-, wIihIi, in tnrn, ri'i'L'ivcs 

 a supply of nutriiu'ut from tlie fungal >ystfni. 



16a 



