THE CANADIAN HORTICULTURIST. 



24T 



seen. The part marked c represents 

 the thin walled elongated cells near the 

 upper surface, and d the irregularly 

 arranged cells near the lower surface, 

 -with large spaces between them. 



The fungus begins as a small swell- 

 ing on the tissue of the upper half of 

 the leaf and spreads until it effects 



^n^ 



S33X 





Fig. 2. 

 nearly the whole surface. The leaf 

 becomes nearly doubled in width, and 

 greatly increases in thickness, and soon 

 after the fungus is matured the leaf 

 shrivels and drops. 



Fig. 2 shows a vertical section of a 

 leaf thus affected and swollen out of its 



normal thickness. In this a is the 

 upper, h the under surface as in Fig. 1 . 

 The cellular structure in the under 

 portion of the leaf is very little changed 

 but that in the upper part has changed 

 materially. The walls between the row 

 of cells under the upper skin or epider- 

 mis, have become much thickened ; the 

 long narrow cells have become swollen 

 and divided, and have become nearly 

 empty, and hence the tendency in the 

 leaf to curl underwax'd. 



The dark lines represent the vege- 

 tative portion of the fungus, coiTeapond- 

 ing to roots. This penetrates the sur- 

 face of the leaf and there forms 

 numerous branches, each of which en- 



sw3P 



Fig. 9. 

 larges and forms the fruiting portion 

 or ascus, shown at a in Fig. 9. In these 

 asci the spores (or seeds) are produced, 

 from six to seven in each, and these 

 are the source of the constant spread 

 of the disease. 



As fruit growers we are pleased to 

 know the cause of such a wide spread 

 evil as the curl of the peach leaf, an 

 evil which has been gaining ground 

 upon us of late, and in wet seasons 

 stripping our trees almost bare of leaves, 

 and lessening the yield of fruit very 

 materially. But if some one could 

 tind a remedy for us, we will be 

 still more grateful. ^ 



