

186 MISSOURI BOTANICAL GARDEN 



d they died down to the base as the disease progressed 



its course. 



began to dry, a grayish 



appeared upon them 



This was at once perceived to be composed of the fruiting bod- 

 ies belonging to Botrytis vulgaris. These fruiting bodies were 

 formed within about two days after the beginning of the at- 

 tack. If allowed to run its course, the disease invariably at- 



affected 



f 



mvcelium 



of the fungus, while all over the outside were the fruiting 

 bodies crowded thickly together. 



After the first few flowers became affected, the disease 

 spread very rapidly and caused considerable damage. Many 

 of the finest blooms had to be removed as soon as they opened, 



thus defeating the 



The 



fungus, so far as could be determined, seemed to exhibit no 

 partiality toward any one variety and counts showed that 

 no one color of blossom was more often attacked than an- 

 other. During the next two years, at about the same period, 

 in the growth of chrysanthemum plants exhibited by the 

 Botanical Garden, the disease has occurred in varying inten- 

 sity. The first season it started earlier in the development 

 of the flowers than it has since done, and for that reason, 

 caused a greater amount of damage than at any other time. 

 During the months of November and December, 1906, a 

 Botrytis disease of "poinsettias" (Euphorbia pulcherrima) 

 was noted in the same house in which two years before had 

 occurred the above mentioned Botrytis rot of chrysanthe- 

 mum petals. In this case the fungus attacked the slightly 

 projecting angles on either side of the leaves. It did not 

 attack the red, bright colored leaves at the top of the plants, 





stem 



belo 



ppeared 



deadened area at the very tip of the angles, which showed 

 beneath tiny white drops of the hardened juice along the 

 larger veins. The fungus seems to attack the tissues in such 

 a way that the white juice of the plant finds exits and exudes 





