28 British Uredinee and Ustilaginee. 
CHAPTER V. 
UREDOSPORES. 
THE uredospores may be developed from mycelia pro- 
duced from the entrance of the germ-tube of an zcidio- 
spore, a promycelial spore, or another uredospore. The 
uredospores are developed singly on the ends of separate 
mycelial hyphz (sterigmata, basidia). Their development 
is as follows:—the mycelial hyphz in the affected host- 
plant at certain points become interwoven and intertwined, 
and the hyphz which constitute these favoured points are 
more richly branched and more freely septate than is the 
case in other parts of the host-plant. In them may be 
observed a number of orange granules. The hyphe are 
so crowded together in the spore-bed, that to a great 
extent they lose their individual outline. Spore-formation 
takes place, first towards the centre of the bed, and then 
extends centrifugally. The mycelial aggregations take 
place just beneath the cuticle of the plant, to which their 
upper surfaces are parallel ; they are termed spore-beds, or 
sori (sporenlager, stroma, hymenia, clinodes). Each spore- 
bed consists of an accumulation of hyphe, which ramify 
in all directions ; but those hyphz that are nearest to the 
cuticle of the host-plant give off a number of branches 
parallel to each other, at right angles to the spore-bed’ 
below, and the host-plant cuticle above. Each of these 
