peer erer 
GYMNOSPORANGIUM CLAVARIZFORME 51 
the disease does appear, spraying with Bordeaux mixture is the 
best remedy against its spreading. It is the very young shoots 
and the upper side of the leaves that most require spraying ; 
although the pustules appear chiefly on the lower surface of 
the leaves, there can be little doubt that infection by the 
basidiospores takes place mainly through the upper surface. 
Gymnosporangium clavarieforme. 
THE HAWTHORN AND JUNIPER RwsT. 
This fungus produces its zcidia on the branches, leaves and 
fruit of the Hawthorn and on the leaves of the Pear, and its 
teleutospores (there are no uredospores) on branches of the 
common Juniper, where it causes fusiform swellings. There 
are three other allied British species, of which G. Sabinae also 
attacks the Pear, but its teleutospores are formed only on 
Juniperus Sabina (the Savin Juniper). 
On the swollen branches of the Juniper, the parasite pro- 
duces in April and May numerous orange masses, which ooze 
out and sometimes reach more than 
1 cm. in height. They vary in 
shape, but are usually more or less 
conical or tongue-shaped (Fig. 30). 
They consist of a mucilaginous 
mass in which large numbers of 
teleutospores are embedded. The 
mucilage is produced by the gela- 
tinisation of the cell-walls of the 
fungus, especially of the very long 
pedicels; it naturally swells and 
becomes more conspicuous in wet 
weather. The teleutospores ger- 
minate at once, while still in the His Sh. Byanasnatoupin Bie 
mass; the basidiospores are pro- variaeforme. Masses of teleuto- 
: te spores on branch of Juniperus 
duced in the usual way; it has communis (slightly reduced) ; 
been shown lately in another species _‘*w° teleutospores, x 600. 
(Coons, 1912) that they do not fall off, but are jerked off the 
4—2 
r~— 
