14 HUMPHREY 



the same stimulus, a;? they were not infected by hyphas. The 

 fungus associated with Aneiira differs from that attacking Fos- 

 sojnbroiij'a both as to development and habit of growth. In the 

 case of the Fossomhronia fungus we find it to be more truly 

 endophytic, once infection has been brought about, while the 

 fungus associated with Aneu7'a seems to be epiphytic in habit, 

 developing haustoria-like branches which in turn develop other 

 branches penetrating and drawing sustenance from the host 

 cells. The hyphas are septate and profusely branched, especially 

 within the tissues of the host. The hyphee within the rhizoids 

 are in nearly every instance unbranched and in no case were 

 they seen to grow through the wall of the rhizoid communicating 

 with the exterior as in Fosso-jubronia. 



The physiological effect of the fungus upon the host is quite 

 as marked as any we have yet studied. The cell walls of 

 Aneuj'a are very much thicker than those of most of our liver- 

 worts, and the plants are vigorous in habit. Each cell contains 

 usually one large oil body and numerous chromatophores. 

 Fungal hyphae penetrate the cell walls without any resulting 

 modification and in some instances a single branch may pass 

 through several cells without producing haustoria or branches 

 of any sort. Ordinarily, however, after entrance to the host 

 tissues is effected, the fungus becomes quite extensive, as seen 

 in Fig. 13, where three affected cells are represented. In these 

 it will be observed that the large oil body has already disap- 

 peared and the number of chromatophores is somewhat below 

 the normal (compare Fig. 12 with Fig. 14). Ultimately the cells 

 become in some instances packed with hyphje and at this stage 

 the death of the cell rapidly ensues. Such cells when micro- 

 chemically tested are void of starch, no nucleus or cytoplasm 

 can be made out, and the chromatophores have undergone 

 complete disorganization ; in fact, little remains but the cell wall. 

 In certain plants where the fungus had reached an advanced stage 

 the hj^phas within certain cells had developed into knot-like 

 structures suggesting the beginning of sclerotia ; and in a few 

 instances these had, when sufficiently nourished, developed into 

 blackish thick-walled sclerotia completely filling and distending 

 the cell cavity. These, in appearance and structure, very much 



