IO HUMPHREY 
consideration. In Afonoclea the fungus is confined to a sharply 
defined mycorrhizal zone three or four cell layers in thickness. 
Many of the cells in this zone are filled with branched hyphe, 
tufts of which seem to envelop the nucleus. In some cases 
even the chromatophores, like the nucleus, become surrounded 
by similar tufts of branching hyphe in a manner quite sug- 
gesting the formation of a lichen. 
In Fossonbronza the hyphe preceding the development of a 
sclerotium are but sparsely ramified. The first indication of the 
sclerotium is the increase in diameter of the hyphz within a cell 
followed later by the profuse development of short, thick 
anastomosing branches between which may at first be seen 
spaces of varying size which ultimately disappear as the 
sclerotium increases in extent (Fig. 10). The nucleus and 
chromatophores at first visible finally disappear, doubtless being 
taken up by the actively growing fungus. As yet the writer 
has failed to observe how these structures are consumed. 
According to Czapek' the tissues of MWarchantia, Fegatella, 
Lunularia and other hepatice contain an antiseptic principle 
which he calls ‘‘sphagnol” because of its abundance in the 
peat-mosses. He has shown that this substance exists in com- 
bination with the cellulose of the cell-walls and exerts an 
inhibitive influence upon the development of moulds and 
bacteria. This, Cavers’ thinks, suggests the view that in the 
case of certain Fusarium-like fungi the ‘*‘ sphagnol ” may serve 
to regulate the growth of the fungus and prevent symbiosis 
from passing into parasitism. In the case of Hossombronza it 
cannot be shown that at any time during a period of infection the 
invading fungus maintains a symbiotic relation with reference 
to the host, for an examination of infected cells shows that the 
presence of hyphz sets up a disturbance of the cell-metabolism, 
the cell becoming impaired to such an extent as ultimately to 
cause its death. The degree of this impairment varies with 
the activity and extent of the parasite. To be sure, many 
infected plants appear to be quite as healthy and fertile as 
1Czapek, 1889: Zur Chemie der Zell membranen bei den Laub. und Leber- 
moosen. Flora, Band 86, p. 361. 
JOG: Cit:, p.'33- 
