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MILDEW AND BRAND. 59
and tlie microscope^ we proceed to examine tliem
in tlie same manner as we have already examined
tlie mildew, and as a result of sucli proceeding
arrive at tlie following conclusions :— Tlie pustules
are small and round^ never elongated as in tlie corn
mildew, and generally confined to tlie under surface
of tlie leaves (plate IV. fig. 69)
. The spores are subglobose,
slightly constricted, and the two cells nearly
two hemispheres, with their flat surfaces turned towards
each other (fig. 70)
. The form delineated in
figure 75 is that of the sorus of many of the epiphytal
brands, the centre being occupied by the
closely-packed spores, surrounded to a greater or
less extent by the remains of the ruptured
epidermis.
Although the species of Puccinia (P. glechomatis)
found on the leaves of the ground-ivy
is said to be
very common, we sought
it in vain amongst every
cluster of that plant met with during last summer
and autumn, until, nearly despairing of finding it
at all, we at last encountered a plot of ground-ivy
covering the ground to the width of two or three
yards, and in length eight or ten, nearly every plant
being attacked by the brand. This was in the
corner of a pasture, and the
only time we found
infected plants. The fungus, however, may be as
common as the plant in other localities. The pustules
on the leaves are larger than those of the
mints, and also confined to the inferior surface
(fig. 78) . The
spores are elliptic
and but slightly