196 
Ridler. — The Fungus present in 
Nemec (1899) identified the fungus in Calypogea trichomanes as an 
Ascomycete, Mollisia Jungermanniae. This fungus bore bluish-green 
apothecia, and covered the plant with a web-like mycelium. Where the 
mycelium penetrated the cells of the leaves or stem the cells lost their 
protoplasm and became discoloured. 
Humphreys (1906) recorded the occurrence of tuberous swellings on the 
stem of Fossombronia longiseta which contained a fungus, but he neither 
described the fungus nor indicated its relationship to the plant. 
Czapek (1889) stated that the tissues of Fegatella , Marchantia , and 
Lunularia contained an antiseptic substance, 4 sphagnol ’, which existed in 
combination with the cell-walls and exerted an inhibitory influence on the 
growth of bacteria and moulds. Cavers has suggested the view that the 
sphagnol may serve to regulate the growth of the fungus, and to prevent 
symbiosis from passing into parasitism. 
Coulter, Barnes, and Cowles (1911) referred to the occurrence of 
endotrophic fungi in mosses and liverworts, and various theories were 
mentioned by them to explain the significance of this symbiosis. They 
noted that in the Bryophyta fungal symbiosis seems to cause diminished 
rather than increased luxuriance and that probably the fungus alone Is 
benefited. 
W. G. P. Ellis (1897) described a disease caused by a fungus on 
Pellia epiphylla in the Botanic Gardens, Cambridge. The fungus produced 
a cobweb-like mycelium over the thallus and fructifications consisting of 
branched aerial conidiophores bearing clusters of round conidia. Septate 
hyphae resembling those on the outside of the thallus were also found in 
the cells of the plant, chiefly in the uppermost layers of cells, except in 
what are termed the ‘rejuvenation shoots’. Cultures were made from 
spores removed from the spore clusters on the host, on nutrient gelatine ; 
these grew to form mycelia which produced similar fructifications. Spores 
from these latter were used to inoculate the sterile apices (or rejuvenation 
shoots) of plants of Pellia epiphylla growing in the infected area, also other 
plants which were brought from a distance, and showed no trace of the 
disease. The spores put out germ tubes which penetrated the upper 
epidermis of the host and entered the interior. Ellis found that the fungus 
did not enter by the rhizoids, but only through the upper surface of the 
thallus. The walls of infected cells became brown, the protoplasm shrunken, 
the chloroplastids lost their colour and became massed together. Ellis 
identified the fungus as the conidial form of an Ascomycete, similar to, if 
not identical with, the Trichoderma-phase of Hypocrea . There are several 
important differences between the chief characteristics of the disease 
described above, and those of the subject of the present investigation. In 
the latter the fungus enters by the rhizoids, is present only in the lower 
portion of the thallus, and is never in the upper superficial layer or the one 
