139 
1917-18.] Pliy corny cetous Fungi. 
appeared in its best condition in the parenchymatous cells of the leaf-bases 
of a species of Lepidodendron (probably L. fuliginosns) from the Upper 
Foot Mine, near Littleborough. 
Habit. 
The hyphse occur in the cells of the leaf-bases of Lepidodendroid plants. 
A few of these cells are shown in Plate, fig. 5. In this figure it was not 
possible to show the whole of the fungus within the field of the microscope, 
because the threads were placed in different planes. When all these were 
gathered up in a single drawing, the fungus at this point presented the 
appearance shown in text-fig. 5. In another slide, hyphrn, very probably 
Fig. 5. x 250. 
belonging to the same fungus, were observed to have extended their rami- 
fications beyond the leaf-base of a Lepidodendron to an adjacent object 
lying in the same mass of vegetable debris. This seems to indicate that 
its habit was saprophytic rather than parasitic. The hyphoe and repro- 
ductive organs are confined within the cells of the host. 
Mycelium. 
The majority of the hyplioe varied in thickness from 2/j. to 4 ju, but a 
large percentage showed an extraordinary amount of variability in the 
thickness of the threads. In most cases, if a single hypha be followed in 
its course a gradual change in thickness is perceptible ; in some the change 
is very abrupt (see Plate, fig. 6). Again, on the same thread are formed 
branches of equal thickness to itself, and also others very much smaller. 
In text-fig. 5 an example of the former type is shown at a, whilst at? the 
points b the branches there formed measure only 1/u in thickness. A very 
marked and somewhat exceptional example of this variation is given An 
text-fig. 6. The thinnest of the threads — in some cases measuring even 
