Medical Officers of the Army of India.
75
long cells stain deeply with all ordinary stains, as will be seen in the figure, whilst
others do not take the stain so readily.
The œcidia are long, somewhat flask-shaped or cylindrical bodies, very
deeply sunk in the hypertrophied leaf tissue. Their bases, indeed, rest almost
directly upon the palisade cells (Fig. 3, Pl. II). Each æcidium is situated on a
minute papilla. The portion of the structure sunk beneath the level of the
lower epidermis is about 0.756 m.m. in length, whilst the part projecting free
is from one to 2 m.m. in length.
The peridium consists of a single layer of gray or pale dirty yellow cells, all,
except those at the very summit of the free part, being considerably longer than
they are broad. Those about the middle measure about 70 x 22μ ( Fig. 11a,
Plate II). These cells are beset, specially on the inner surface, with prominent
Short irregular ridges. They are united to one another in longitudinal series as
follows. The upper end of each cell is bevelled like a chisel, the sharp edge
overlapping internally the lower end of the cell above. The lower edge of each
cell is similarly bevelled, but in the opposite direction, so that it overlaps the
upper bevelled end of the cell below externally (Fig. 11b, Plate). In teasing
the tissue of the peridium it is seen that the cells are easily detached from one
another laterally, but are firmly united to one another by their ends. The peri
-
dium dehisces by the formation of numerous irregular slits in its side, and also
opens freely at the summit, the tube retaining its original form throughout the
time the spores are being shed. A few æcidiospores may always be seen
sticking in the meshes of these slits. The majority of the spores would appear
to fall out through the opening in the summit.
The œcidiospores are round, or oftener oval, when free and moist, but when
dry are often facetted. They are given off serially from a hymenium of long
regular basidia; the hymenium measuring about 60 μ in depth. They are pale
brown, beset densely externally with minute tubercles, and measure when just
wetted 28.6 X 24.6μ on an average (28μ diameter in round to 31 X 25μ ).
Placed in water, they germinate readily, throwing out in 24 hours a long, much
branched, germ tube (Fig. 12, Plate II). In such cultivations I could not assure
myself that there were any slit-like openings in the endospore, as described by
Rees,1 n o r a n y b u l g i n g i n w a r d s o f t h e e n d o s p o r e o p p o s i t e t h e g e r m p o r e s , o f
which there are usually six, but sometimes eight.
The spermogonia are, as usual with this group of Uredines, very large and
prominent. When ripe, their orifices are covered with a clear glistening sticky
fluid, probably secreted by the well-developed tuft of paraphyses, which, arising
from the very base of the structure, protrude about 50 to 60 μ beyond the
orifice. They are deeply sunk in the leaf tissue, their bases pushing down, and
partly disintegrating, the upper palisade layer. The effect of Spiller's purple
upon these structures is somewhat peculiar, as, while the sterigmata are coloured
1 D i e R o s t p i l z f o r m e n d e r d e u t s c h e n C o n i f e r e n , D r . M a x R e e s s , 1 8 6 9 .
L2