South African Perisporiaceae. 121 
Gueguen's triple stain. I think it is probable that the species M. amplii- 
tricha as at present constituted consists of a number of species which are 
morphologically similar, and that the form of the haustoria should be taken 
into consideration by taxonomists. 
The third species parasitic on Olea laurifolia is Ire^ie ditricha (K. & Cke.), 
Doidge, which occurs on the upper surface. The penetrating filament is 
thin walled, staining blue ; it traverses the cuticle and the epidermal cell and 
expands into a globular vesicle just inside one of the palisade cells. It thus 
differs from the first of the fungi described on this host only in the broader 
penetrating filament, which in this case is about 1-5 /x thick. 
Irene ditricha also occurs on Celastrus sp. ; the form on Olea laurifolia 
differs in one or two minor points, and should perhaps be considered a 
variety. The leaf of this plant becomes discoloured over a considerable 
area, the centre of which is the Meliola mycelium ; the discoloured parts 
become yellowish brown. This fact makes the leaf rather an unfavourable 
one for study as the contents of the epidermal and hypodermal cells are 
badly disorganised and stain deep blue. The haustoria appear to be similar 
to those of J. ditricha on Olea laur folia. 
Meliola carissae Doidge occurs on Carissa arduina, which has a leaf with 
a very thick cuticle. The penetrating filament is fine, staining blue, but its 
walls are often brown or brownish for a short distance where it enters the 
cuticle. The vesicle is in the epidermal cell, and is of the usual type, thin- 
walled, globular, hyaline and uninucleate. 
Meliola leptidea Syd. on Cussonia umhelVfera has also what may be 
termed the ordinary type of haustoria, with a fine penetrating filament and 
a globular vesicle in the epidermal cell. These are very small and incon- 
spicuous, but the contents of the epidermal cells are obviously disorganised 
and filled with a granular deposit. 
This type of haustorium was also produced by Meliola, ganglifera K. & 
Cke. on Curtisea faginea and M. capensis (K. & Cke.) Th. on Hippohromus 
alatus. 
Meliola bifida Cke. on Osyridlcarpus natalensis occurs on the stems, and 
no satisfactory preparations could be obtained of this species, as the stem was 
too hard to cut with the freezing microtome, and the fungus very readily 
became detached from the host. 
Meliola Evansii Doidge is found on Scolopia sp. Here the haustorium 
penetrates to the hypodermal cell (Fig. 1). The penetrating filament is hyaline 
and stains blue, but is fairly stout, and the expanded vesicle is formed in 
the chlorophyll-containing cell of the mesophyll which is encountered. 
Exceptionally clear preparations were obtained of Meliola arcuata Doidge 
on Viscum anceps (Fig. 2). The stem — it is a leafless species of Viscum — 
has a very thick cuticle which is traversed by a fine penetrating filament, 
and swells into a globular uninucleate vesicle just inside the epidermal cell. 
