120 
W. T. THISELTON DYER. 
From the first appearance of th<^ disease its serious charac- 
ter was recognised. Specimens of the diseased leaves were 
sent to this country, and were examined by the Rev. M. 
J. Berkeley, who named it Hemileia vastatrix, and published 
a short notice describing it in the ^ Gardener^s Chronicle ’ for 
1869 (p. 1157) with a figure.^ He not merely determined 
it to be quite new to science, but with difficulty referable 
to any recognised section of fungi.” He considered it to be 
intermediate between Mucedines and TJredinei, a view 
which is not sustainable since the Rev. R. Abbay ^ and 
Mr. Morris, after working upon the plant in a fresh 
state, have both agreed in affirming that the reproductive 
bodies regarded by Mr. Berkeley as spores are in reality 
sporangia. This observation widely alters any possible 
view of the affinity of the fungus, but it has not, so far, 
led to any very definite systematic position being assigned 
to it. 
The coffee tree is an evergreen, and the speedy effect of 
the attack of the fungus upon its young leaves is to cause 
them to fall off, leaving the tree almost bare. After a time 
it throws out fresh healthy-looking foliage. Sooner or later 
this in its turn exhibits the fatal spotting, and is shed pre- 
maturely. It is said that there is no known instance of 
coffee trees being actually killed by the attacks of the 
disease, but they become much enfeebled by the repeated 
loss of foliage and eventually become worthless as crop 
producers. 
The following pages give in a condensed form the net 
result of the investigations to which the life-history of the 
Hemileia has been subjected. The plates have all been 
drawn from drawings by Mr. Morris, and have been borrowed 
from a book which he is preparing for the use of the Ceylon 
planters. 
To the naked eye the first appearance of the Hemileia 
is indicated by a slight transparency or palish discolour- 
ation,” easily noticed when the leaf is held up to the light. 
These transparent spots indicate the points where infection 
of the leaf has begun. As the ‘‘ spot ” becomes larger and 
older it assumes a faint yellow colour ; ultimately on the 
under side of the leaf it becomes covered with a bright 
yellow dust, and this later on changes to a bright orange. 
(Plate IX, fig. 1, represents the under side of a coffee-leaf 
in a diseased state.) The discoloured patches are irregular 
1 Reproduced in ‘ Quart. Journ. Mic. Sc.,’ 1873, p. 80. 
2 * Journ. Linn. Soc. Bot.,’ vol. xvii, p. 176. 
