PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATICyE 1 7 



hyphae produce short lateral processes which grow in length 

 until they come in contact with a similar branch of a neighbor- 

 ing hypha effecting conjugation with it ; or in case it fails to 

 meet with such a branch it is seen to anastomose with a near- 

 by hypha and in this manner a complicated weft of hyphae may 

 develop over the surface of the host. The same seems to be 

 true with regard to the hypha; within the host cells, though to 

 less extent. Within certain cells (Fig. 19) dark colored scle- 

 rotia-like structures develop, though in the material studied 

 these were by no means abundant. With a limited amount of 

 infected material nothing definite can be said as to the relation 

 of the fungus to the host. All plants examined however seemed 

 practically unaffected by the fungus. Infected cells exhibited 

 the single chromatophore in every case except where sclerotia 

 had formed. Just what would have been the effect had the 

 fungus been as far advanced as in the case of Fossomhronia or 

 Aneura is mere conjecture. Our species of Anthoccros have, 

 growing within the thallus, colonies of a species of Nostoc^ but 

 the writer saw no evidence of fungal hyphas invading these. 



Porclla holandcri is infected by a fungus of somewhat dif- 

 ferent habit, though its ultimate effect upon the host is not 

 greatly different from what has been described for Fossombronia 

 and Aneiira. 



The principal hyphal trunks appear for the most part to be 

 intercellular, thus differing in this respect from the others 

 described above. A single hypha finding entrance to a leaf for 

 example, will ramify to some extent, and these various primary 

 branches grow along between the cells of the host, thus forming 

 an intercellular complex that may effect nearly every cell. 

 From these primary branches, haustoria find entrance to the 

 host cells and here they become more or less branched, with the 

 result that the cells lose all their contents except the nucleus ; 

 this seems to persist. After the disorganization and disappear- 

 ance of the chromatophores, the fungus structures are easily 

 visible and in many of these cells may be seen exceedingly 

 thick-walled chlamydospores, in some instances quite filling the 

 enclosing wall of the host cell (Fig. 17). 



The fungus is not confined wholly to the interior of the tissue. 



Proc. Wash. Acad. Sci., January, iqoS. 



