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CHAPTER IX. 
FORMATION OF THE TELEUTOSPORES OF THE 
USTILAGINE. 
WHILE it is true that the spores of Ustilaginee are formed 
from the mycelium, yet the process does not take place 
directly from the vegetative mycelium which has just been 
described. On the contrary, at those favoured parts of the 
affected, host-plant at which the spores are developed the 
vegetative mycelium often quite suddenly changes its 
character. The double-contoured hyphe with pellucid 
vacuolate contents lose their double contour, become 
swollen or distended, and contain, instead of a clear watery 
fluid, a gelatinous, granular protoplasm. in which numerous 
oleaginous particles may often be seen (Plate V. Figs. 3-6). 
The gelatinization of these spore-forming hyphz is a great 
character of the Ustilaginez ; it does not, however, occur 
in all species. The first change observable in the mycelium 
before it becomes a spore-forming hypha, is that its walls 
increase in thickness at the expense of its calibre, which 
becomes proportionately diminished ; soon, however, the 
whole hypha becomes dilated, so that its lumen is increased. 
Its contents can now, by the action of reagents, be shown 
to consist of protoplasm. Spore-formation takes place, 
after these changes in the mycelium, so differently in the 
different genera that it will be necessary to describe the 
process, as it takes place in each one, separately. 
