STOMATAL PENETRATION 



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Fig. 44. Types of appressoria. A. Appressorium of urediniospore at stomatal 

 aperture. B, C, and D. Appressoria formed by one of the anthracnoses, as 

 an early stage in germination. B. In culture a hypha arises from the appres- 

 sorium. C. In the host the appressorium anchors the organism, and the 

 slender penetration tube arises from beneath the appressorium. E and F. 

 Appressoria formed by Diplocarpon rosae. (After Aronescu.) 



