14 HUMPHREY 
the same stimulus, as they were not infected by hyphe. The 
fungus associated with Azeura differs from that attacking Fos- 
sombronza both as to development and habit of growth. In the 
case of the /ossombronza fungus we find it to be more truly 
endophytic, once infection has been brought about, while the 
fungus associated with Azeura 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 hyphe are septate and profusely branched, especially 
within the tissues of the host. The hyphe 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 Hossombronza. 
The physiological effect of the fungus upon the host is quite 
as marked as any we have yet studied. The cell walls of 
Aneura 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 hyphz 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 hyphe 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 hyphe 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 
