BOTRYTIS UPON CHRYSANTHEMUMS AND POINSETTIAS. 187 



through these weakened spots, hardening qui< 

 exposed to the air. These small, hardened 



seem to be 



being found 



of 



nection with this trouble ; the very earliest stages 

 ease could be found only by looking at the under sides of 

 the leaves, and noting the presence of this dried juice at the 

 angles of the leaves. In the earliest stages the leaf tissues 

 upon the upper side gave little or no indication of being dis- 

 eased, although there usually was a slight yellowish discolora- 



tion. 



becomes 



larger and the extreme tips of the affected angles wither 

 and become discolored; this dying of the tissues progresses 

 toward the mid rib of the leaf as the fungus extends its field 

 of action. In no case, however, did the Botrytis disease alone 

 seem to extend over the whole area of the leaf. On the other 

 hand, after the disease had progressed until it involved 

 about one-fourth the area of the leaf, the effect seemed to be 

 communicated to the petiole, and the leaf was prematurely 



shed 



damage was done 



fungus, since the badly affected plants consisted only of a 

 bare stem surmounted by the broad whorl of red leaves at 

 the top. The absence of the green leaves greatly marred 

 the plants for exhibition purposes. About two days after a 

 leaf is first attacked, the characteristic fruiting bodies of 

 Botrytis are formed in thick groups, clothing the under sur- 

 face of the affected area. 



In the same greenhouse a number of plants of Primula 



obconica grandiflora 

 diseased by Botrytis. 



in 



stemmed 



flat on the surface of the soil, thus giving the fungus the 

 best of opportunities for attack. In this case the affected 

 1 paves finallv entirelv succumbed to the disease, and it even 



from the diseased 



ones. 



parasitism of Botryt 



and petals of the above mentioned plants. No ex- 



