PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATIC^ 7 



hyphai, though the more compact tissue of the thallus was in 

 many such instances thorough!}^ infected. Thus it would seem 

 that infection need not necessarily take place through the rhi- 

 zoids. Material carefully fixed in chromic acid (i per cent.) 

 and stained with the Fleming's triple combination seemed to 

 give very satisfactory results, though it was found necessary to 

 allow more time to the action of the stain than was customary 

 in staining organs or structures of the host. Sections through 

 the stem of infected plants almost always showed a well-de- 

 fined zone of cells more or less given over to hyphai. This is 

 not unlike the condition observed by Cavers ' ('03) in Fcgatella 

 and by Golenkin" ('02) in a number of forms cited above. 

 Golenkin states that the cells of this zone, though still retaining 

 their protoplasm and nuclei, are void of chlorophyll and starch. 

 Careful examination of infected cells of Fossoinbronia^ except 

 where infection was so far advanced that the cells were occu- 

 pied by developing sclerotia, revealed the presence of varying 

 amounts of chlorophyll and starch, depending upon the number 

 and vigor of invading hyphee. 



Unlike the forms described by Golenkin, this fungus is not 

 necessarily confined to any given zone, for any portion of the 

 thallus may be invaded by hyphas extending out from the more 

 compact parts. Though several hundred fruiting plants have 

 been studied, no evidence of infection of either antheridium or 

 archegonium has yet been seen, and the sporophyte is appar- 

 ently free from the attack by fungus. 



In material fixed in January, 1904, about three months after 

 the beginning of the rainy season, almost the entire tissue of the 

 stem was packed with hyphag, many branches extending through 

 the outer layer of cells of the host into the substratum. 



Although the fungus was present in virtually the whole of 

 the stem-tissue, strictly speaking, it was found that at this stage 

 of its development the hyphas were more or less confined to the 

 innermost cells of the stem while those in proximity to the 

 growing point as well as the leaves were apparently free from 

 infection. The epidermal cells and those immediately beneath 



* Loc. cit., p. 33. 



* Loc. cit., p. 209. 



