4 HUMPHREY 



THE PARASITIC FUNGUS ASSOCIATED WITH FOSSOMBRONIA 



LONGISETA AUST, 



In the writer's recent studies on the Development of Fosso^n- 

 bronia longiseta ^ no reference was made to the structure of the 

 infecting fungus ; in fact, the material then in hand was too 

 scanty to make anything like a satisfactory study. Since the 

 publication of the above paper, however, excellent material has 

 been found in various stages of development, and the relation of 

 fungus to host has been clearly worked out. 



So far as could be ascertained, the host is invaded from with- 

 out by hyphae; that make their entrance through the rhizoids or 

 directly through the cells of the host stem. The infection of 

 the rhizoids is very similar to that described by Cavers^ for 

 Lofhozia, Ce^halozia and other hepaticse. As a rule the 

 hyphag not only invade the rhizoids but extend throughout the 

 tissues of the host, regardless of the nature of the substratum, 

 thus differing somewhat from the nature of infection reported 

 by Cavers where he has observed that the degree of infec- 

 tion varies with the amount of humus in the soil. In Fos- 

 sombronia, as a rule, the hyphge infecting rhizoids alone were 

 confined to the inner wall of the organ, though in some instances 

 not a few rhizoids were found in which hyphce had penetrated 

 through the wall to the exterior as shown in Fig. 3. The host 

 thus affected was growing in soil containing little humus and 

 in no case were these external hyphse observed to grow longer 

 than those figured. The hyphae confined to the rhizoids are 

 very seldom branched and are rather remotely septate. In cer- 

 tain parts, however, usually at the end of a branch, short seg- 

 ments not unlike conidia develop and are abstricted from the 

 hypha. The subsequent behavior of these has not been 

 observed. It is, however, quite probable that these structures 

 furnish one means of transfer of infection. I did not find in 

 Fossoinbronia anything comparable with the conidia described 

 by Jeffrey^ as occurring in the endopliyte of Boi7'ychiwm vir- 

 gintanum. 



' Humphrey, 1906 : The Development of Fossombronia longiseta Aust. Annals 

 of Botany, Vol. XX, No. LXXVII. 

 ^Loc. cit. 

 'Loc. cit. 



