i, 
DISEASES OF PLANTS DUE TO FUNGI. 
By A. Lorrain Smith. 
GLOEOSPORIUM TILIAE OUD. 
An instance of loss caused by this fungus was brought unde 
my notice in June of this year. ~ The leaves of some lime trees 
‘1 Oxfordshire were stripped from the branches in large numbers 
during a gale of wind. There had been severe cold and frost, 
which might have injured the leaves; and there had been a hail- 
storm, which had undoubtedly torn and injured the foliage. 
These factors, however, did not seem sufficient to account for 
the damage done, especially as the leaves when they fell were 
at their fullest vitality. The owner of the trees had noticed 
black patches on some of the leaves and, on the petioles of those 
that had fallen, a small burnt-like spot was nearly always pre- 
sent at the point of rupture. 
Microscopic examination shewed that the blackened areas 
were due to the death and discolouration of the cells of the 
cortex, and on these were seated the small pustules of a 
Gloeos porium, a fungus belonging to the Melanconieae group of 
Fungi imperfecti. The injury in some cases had not gone any 
deeper than the superficial layers of the cortex, in others the 
mycelium had penetrated to the bundle strand and corroded 
half-way through the tissue of the stalk. The damage done to 
the conducting tissue was in no case sufficient to kill the leaf 
or to sever its connection with the branch, but the weakened 
petiole was no longer able to resist the force of any strain, and 
the wind had been the final agent of destruction. 
The spots on the leaves were also caused by the same fungus. 
They were characterized by a central grey portion, visible on 
both surfaces, the decolouration being caused by the parasite 
having destroyed the contents of the cells; the Gloeosportum 
pustules looked like tiny blisters scattered over the discoloured 
spots: a dark line surrounded each patch. 
Gloeos porium, like other Melanconieae, does not form a de- 
finite fruiting body. The one-celled spores are borne at the 
tips of short upright hyphae, which rise from a compacted base 
of fungal hyphae, localized in little masses and formed under 
the epidermis of the host plant. The swelling of the epidermis, 
which bursts at a definite central point to allow the escape of the 
spores, gives, however, more or less the appearance of a peri- 
thecium. The size of the spores found on the Oxfordshire 
specimens varies very much. They measure about 10 @ xX 25 My 
some being much smaller. It has been recorded from Holland, 
Italy and Australia, but only on the blade of the leaf, where it 
