The Fungus present in Lunularia cruciata (L.) Dimi. 91 



from 25-35 nini- ^oi^S ^-i^^ from S-12 mm. broad and were bright 

 green in colour. 



Discussion. 



It is very difficult to determine whether or not the fungus is 

 of any actual use to the liyerwort. The fungus apparently 

 obtains some carboh\^drate material from the hyerwort ; on the 

 other hand, the partial digestion of the fungus, and the possible 

 absorption of the contents of the latter may compensate for 

 the loss. 



The fact that the association is not constant indicates that 

 at any rate under certain conditions in nature the fungus is 

 not necessary for the growth of the plant, that is, the association 

 is not obligate, but purely facultatiye. Reproductiye organs of 

 this liyerwort are yery rare, and none haye been found either 

 on infected or uninfected material used in the present inyestiga- 

 tion, so that apparently the presence or absence of the fungus 

 has no effect on their formation. Gemmae cups are as frequent 

 on infected as on uninfected plants. Neither is there any yery 

 definite ev-idence that the presence of the fungus has any effect 

 on the size of the plants. 



From these facts it appears that the fungus is of little or no 

 use to the liyerwort, and must be regarded as a harmless 

 parasite. 



Summary. 



1. The cells of the thallus of Lunularia cruciata contain a 

 fungus which occurs in a single strand of cells along the thick- 

 ened median portion or midrib, towards the yentr^ surface of 

 the thallus. The occurrence of the fungus howeyer is not con- 

 stant. 



2. The fungus present undergoes partial digestion by the 

 liyenyort, ending in the formation of "arbuscules" and "spo- 

 rangioles"; its gro\\i:h and consequent distribution in the 

 thallus is thus restricted. 



3. Starch disappears from the cells after the entrance of the 

 fungus. 



4. A fungus has been isolated from the thallus and identified 

 as a species of Phoma, but it is not ^-et certain whether this is 

 the true endophyte. 



5. Uninfected plants of Lunularia haye been gro\Mi on an 

 artificial medium. 



6. The fungus obtains carbohydrate material from the thallus 

 as a source of food material. The liyerwort, on the other hand, 

 is not apparently benefited by the presence of the fungus. 



7. The association between the fungus and the liyerwort is 

 considered to be harmless parasitism on the part of the fungus. 



