Medical Officers of the Army of India.
of mycelial invasion, on each of which appear minute pustules, containing
yellowish brown uredospores. These invaded areas are not in the least
thickened, and, as the slight paling of the green tissues caused by the mycelium
is most pronounced on the lower surfaces of the leaves, where only the pustules
are formed, the affection is by no means conspicuous, and in this respect offers
a very striking contrast to the aecidial affection, In the special localities
where the aecidium was formerly prevalent this uredo-affection is especially
prevalent, and the attacked leaves present so many foci of attack that the
circular areas of each separate attack frequently merge into neighbouring
areas, and thus a large area of the leaf's under-surface is uniformly paled, and
bespattered irregularly with uredo-pustules. But, when the leaves are not so
extensively attacked, a very peculiar and characteristic arrangement of uredo-
pustules is evolved. At first, after a circular paled area has been formed by
the mycelium, a uredo-pustule usually breaks out from the centre of the area.
A little later a circle of other pustules is formed around the central pustule.
Later still, a second larger circle, around the first circle, is formed near the
margin of the paled area. But before this last circle is formed the develop-
ment of teleutospores, in the form of puccinia, has commenced in the earliest
formed uredo-pustules, and especially in the first circlet of these. This teleu-
tospore formation begins to take place in November. The originally very small
uredo-pustules enlarge greatly when teleutospore formation sets in, so that the
neighbouring pustules of the circlet often coalesce, sometimes wholly, when a
complete circular wall of teleutospores is formed round the central pustule,
which does not enlarge to any great extent, and which often does not form any
teleutospores, until a much later date. More usually this circular wall of
teleutospores is broken in continuity at one or two places. With the onset of
the winter the continued production of teleutospores goes on slowly, but
apparently more or less continuously, and in the following spring the condition
of the attacked leaves is as follows. Such leaves now exhibit slightly paled
circular patches, varying in number from one to about twenty, without any thick-
ening or hypertrophy. The larger patches measure from 6 to 7 mm. in
diameter and the smallest about 2 mm. The teleutospore beds are aggregated
together circularly in hemispherical dark-brown compact masses (Fig. 2, Plate I).
Sometimes in the smallest paled areas there is only one such bed of spores
in the centre of the discoloured area, indicating the formation in the previous
autumn of only one uredo-pustule, but usually there are two or more segments of
a circle, around a central space, which contains the first formed uredo-pustule
now containing a few teleutospores, with remains of uredospores. When a leaf
has been extensively attacked the circular arrangement, as already explained
is lost, but otherwise the circular teleutospore beds are surrounded by the
second circle of uredo-pustules, about nine to ten in number. This outer-
most circle of pustules contains frequently only old uredospores, and perhaps a few
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