DISEASES DUE TO FUNGI 55 
spores, which are highly resistant to external conditions 
and carry over the disease from one season to another. 
Sometimes the spores are enclosed in tiny flask-like 
structures buried more or less deeply in the leaf, stem, 
or fruit tissues, and being thus protected are able to 
Bassss= 
ayo |r 
Fig. 3. Ae) Hyphae, (0) thin-walled ‘‘summer”’ spores, (c) thick-walled resting spore, 
(d) a a pycnidium, (e) a perithecium, (f) ascus containing eight ascospores. 
resist abnormal conditions. These bodies are of two 
kinds—the pycnidia and perithecia. In the former the 
spores are produced on small stalks which line the inside 
of the vessel; in the latter case a number of small sacs 
are produced within the vessel, each of which contains 
