102 MR. W. G. P. ELLIS ON A TRICHODERMA 
Fig. 3. Similar section, showing development further advanced. 
Fig. 4. Radial section, illustrating connexion of vascular tissue of stem and 
disc. 
Fig. 5. Transverse section, illustrating the formation of hairs from columnar 
cells and the exfoliation of the epidermis. 
Fig. 6. Transverse section through old disc. The outer cells are suberized, 
and a regular periderm is being formed by a cork cambium. 
Fig. 7. Radial section through portion of old disc. At r the tissue beneath 
the cork is giving rise to roots. 
Fig. 8. Similar section, illustrating the connexion of the vascular tissue of 
older root with that of the disc. 
j 
Ona Trifoderma Parasitic on Pellia epiphylla. By W. G. P. 
Euri, Demonstrator in Botany of the University of Cam- 
bridge. (Communicated by Prof. H. Marsnann WARD 
D.Sc., F.R.S., F.L.S.) 
[Read 4th March, 1897.] 
(Prates 6 & 7.) 
Ar the Cambridge University Botanie Garden the Liverworts are 
grown in red earthenware-pans, 12 inches long and 9 inches wide, 
kept in the Filmy Fern house. Early in May 1896 a disease 
appeared in one of these pans in which the thallus of Pelli 
epiphylla alone was growing. At one corner of the pan the 
thallus became diseased, as shown by its colour changing from 
green toa dull brown; and this browning of the thallus extended 
centrifugally over the pan during May and June. 
Thad never before seen nor heard of any special disease of 
Liverworts. They may often be found more or less covered with 
species of Oseillaria, especially when kept too damp and not 
sufficiently illuminated; but here was a definite disease, ob- 
viously epidemie, and which spread centrifugally onwards with 
an ever-increasing margin over the pan (compare figs. 1 and 2 
reproduced from photographs). Professor Marshall Ward sug 
gested that I should examine this disease, and if possible ascertain 
to what it was due. 
For several days nothing further was observable beyond what 
has been described above; but on May 14th there appeared neat 
