2 HUMPHREY 



The author wishes to acknowledge his obligations to Pro- 

 fessor Douglas H. Campbell and Associate Professor George 

 J. Peirce under whose direction the work was pursued. Thanks 

 are also due Professor Alexander W. Evans, Dr. Marshall A. 

 Howe and Professor Roland Thaxter for assistance in the 

 determination of material and for the use of certain hepaticas 

 sent to the writer. 



PARASITISM AND SAPROPHYTISM IN HEPATIC^. 



The association of certain fungi with hepaticse was first 

 described in detail by Leitgeb,^ who, in his studies on PtiUdmm 

 ciltare, observed the infection of young sporogonia. He found 

 that all such sporogonia were more or less abnormal in their 

 mode of segmentation and inferred from this that the infected 

 organs were structurally effected by the action of the fungus. 



Following Leitgeb, a number of writers have observed fungus 

 infection in other hepaticse. As early as 1879, Kny ^ discovered 

 sterile fungal hyphse in the rhizoids of Lunularia and Mar- 

 chantia. These, he states, were found to be present in rhizoids 

 undergoing a process of regeneration, which process may have 

 been stimulated by the hyphae. Cavers^ has observed that 

 when Marcliantia and Lunularia grow in ordinary soil free of 

 humus the rhizoids are penetrated by hyphae which grow up- 

 ward as delicate filaments showing cross-walls at rather long 

 intervals. These hyphaj occasionally become branched but 

 never, so far as he has observed, reach the tissue of the thallus. 

 On the other hand, he has found that when these plants grow 

 on humus soil the hyphee extend into the compact tissue of the 

 thallus, to which in fact, they are largely confined. 



Golenkin '* observed the presence of endotrophic mycorrhiza in 

 Marchantia ^ahnata^ M. paleacea, Pf-eissia commutata^ Tar- 



' Leitgeb : Untersuchungen iiber die Lebermoose, Heft 2, p- 58 ; Tafel 3, 

 Fig. 26. 



''Kny and Bottger, 1S79: Ueber eigentliiimliche Durchwachsungen an den 

 Wurzelhaaren zweier Marchantiaceen. Verhandl. d. bot. Vereins d. Prov. 

 Brandenburg, p. 2 of Separate. 



* Cavers, 1903: Saprophjtism and Mycorrhiza in IlepaticjE. The New Phy- 

 tologist. Vol. II, No. 2, pp. 32-33. 



■•Golenkin, 1902: Die Mycorrhiza ahnlichen Bildungen der Marchanteen. 

 Flora, Band 90, p. 209. 



