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Edwin F. Hopkins 



mycelium from a culture of the onion Botrytis, B. Allii Munn, and with 

 a large sclerotial form of Botrytis from tulips — not B. Tulipae. From 

 both of these inoculations a strong infection resulted on the leaves and a 

 slight infection on the stem, in the uninjured as well as the injured 



plants. A similar experi- 

 ment with mycelium from 

 the same cultures was tried 

 on onion bulbs, and here 

 B. Tulipae produced no in- 

 fection, while the other two 

 species produced a strong 

 infection, but only on the 

 injured bulbs. It is inter- 

 esting to note here that on 

 the uninjured bulbs inocu- 

 lated with B. Tulipae, pecul- 

 iar depressions appeared in 

 the bulb scale that at first 

 seemed to be slight infec- 

 tions. However, microscop- 

 ical examination showed 

 that the mycelial threads 

 had not penetrated. They 

 were merely superficial. 

 Nevertheless, beneath the 

 mycelium some epidermal 

 cells and other deeper-lying 

 cells had been killed. Mi- 

 croscopical sections of the 

 injured bulbs showed my- 

 celium in the punctures 

 made by the scalpel. It had not, however, penetrated laterally into the 

 tissue, although some of this tissue had been killed. 



Inoculation of narcissus.— The result obtained on the narcissus was 

 similar to that on the onion: strong infections appeared on the leaves 

 and slight ones on the stems when the inoculation was performed on 



Fig. 42. result of artificial inoculation 

 The whole top is involved. Natural size 



