1^2 W. T. THISELTON DYER* 
mass apparently becomes so consolidated that the fact of its 
composition from compacted mycelium eluded the observation 
of Mr. Abbay, who thought it was a sac-shaped dilatation 
of a single mycelial filament.^ To Mr. Morris is due the 
credit of clearing up this pointy though Mr. Berkeley, in the 
figure which accompanied his first description, clearly indi- 
cated that the sporangia (or, as he thought them, spores) 
sprang from individual threads. 
Tracing the mycelial filaments further into the leaf, which 
is, of course, reversing the course of their development out- 
wards, they are seen to assume a branching coral-like 
habit (PI. XII, fig. 2, c). They feed on and destroy the 
spongy parenchymatous tissue of the leaf where they come in 
contact with the chlorophyll-containing cells. These are 
broken down, cavities are produced (PL XII, figs. 1 and 2, 
h), and the leaf at these points appears consequently of a 
paler colour. 
When mature the sporangia appear to be readily detached, 
and are liable to be dispersed by the wind or by animals, or 
even the clothes of persons working in or visiting the plan- 
tations. Probably the papillae with which they are covered 
on all but one side give them a mechanical adhesiveness. 
At first the sporangia are filled with dark-red or orange 
granular matter ; when fully ripe they are seen to contain 
a varying number of minute nucleated spherical sporidia, 
ranging, apparently, from one or two to fifteen or twenty. 
According to Mr. Abbay, the sporangia have two coats, an 
outer one, bearing the papillae which disintegrates,” while 
the inner membrane opens out and slowly dissolves away.” 
Mr. Morris, however, finds that in very ripe sporangia the 
smooth surface is ruptured, and the sporidia by this means 
escape. When the sporangia are placed on a moist slip of 
glass resting on damp blotting paper the sporidia begin to 
germinate within twenty-four hours, and for the most part 
inside the sporangium, the mycelial filaments being pro- 
truded through its wall, which softens and gives way before 
it (PI. X, fig. 2, d) ; some germinating sporidia, however, 
are generally found also, which have escaped from the spo- 
rangium (fig. 2, c). The result is that everywhere, after an 
attack of leaf disease, in the neighbourhood of diseased coffee 
trees, whether on fallen leaves, moist surfaces, or on the 
stem or branches, a web of mycelium is produced, by the 
continuous development of which the whole of the exterior 
of the coffee tree is completely invested with the toils of its 
* Loc. cit., p. 176. 
