118 Transactions of the Royal Society of South Africa. 
Maire based his observation on four species : Meliola amphitricha Fr. on 
Schinus molle, M. Negeriana on Lomatia ohliqua, M. hrasiliensis var. 
sanguineo-macidans on Schinus sp., and one of the two European species, 
M. nidulans on Vaccinium myrtillus. 
On examining numerous sections he found small haustoria in certain, 
epidermal cells ; these appear in the form of a yery fine tube with brown 
walls and very clear lumen, which traverses the cuticle perpendicular to its 
surface or somewhat obliquely. When the cuticle is not very thick the tube 
traverses it without any sensible modification, and expands in the cavity of 
the cell into a more or less spherical vesicle with a thin hyaline wall — e. g. 
in Schisms sp. attacked by Meliola hrasilie7isis var. sanguineo-maculans and 
M. ami)hitricha. 
When, on the contrary, the cuticle is thick, the tube completely changes 
its form and contracts into an extremely fine, filiform tract (about -| jj. diam.), 
staining bright blue with lactophenol and cotton blue, in which it is impos- 
sible to observe the protoplasmic membrane. This filiform tract expands 
in the cell cavity in a similar way to the one described above. 
Maire experienced some difficulty in finding sections showing the actual 
connection of the haustoria with the hypha, as the latter frequently fall 
away in sectioning ; but after examining a large number of sections, haus- 
toria were found adhering to the hyphae from which they were produced. 
He concludes from this evidence that the Meliolas are true parasites, 
deriving their food supply from the epidermal cells of the host by means of 
haustoria.* 
The genera Meliola and Irene are well represented in many parts of South 
Africa, and over fifty species have been recorded (4), although there are 
still many promising localities in which no collections have been made. In 
view of the prevalence of these fungi on our forest trees, it was suggested 
to me by Dr. J. W. Bews that they might have an important bearing on 
plant succession in the forest belts. Seedling trees are especially subject 
to the attacks of fungi belono^ing to the genus Meliola, and it is not 
uncommon to find the leaves of seedlings of certain susceptible species so 
covered with dark mycelium that the normal green colour is only to be 
seen where young leaves have recently unfolded. It therefore was a matter 
of considerable interest to discover to what extent the Meliolas are parasitic 
and to confirm and extend the observations made by Maire. 
Dried material from the National Herbarium was employed, and 
although recent collections were chosen where possible, satisfactory prepara- 
tions were obtained even from old material. Small areas covered with the 
mycelium of the fungus were cut out and boiled in 10 per cent, formalin 
* A number of valuable papers by G. Arnaud, containing references to the 
haustoria of the Microthyriaceae and allied families, only came to my notice when this 
paper was in the press, and have not been taken into consideration. 
