y^^^-^M,„, 





The Verbena Disease. — It is now about ten years since the verbena be- 

 came subject to the disease called " black rust : " and, ever since, it has suffered 

 more or less from its effects ; the result of which has been, as might be supposed, 

 much annoyance to cultivators, and disappointment to those who have grown it 

 as a bedding-plant. Being one of those who have felt much inconvenience 

 arising therefrom, and anxious to obtain more correct views as to its nature, I 

 would, with many others, thank any one who would lift the veil which now rests 

 upon the subject. Perhaps in proper hands this might be done, or at least the 

 question put in such a shape as to simplify the process of investigation as to its 

 cause, but more especially how to prevent it. As minute and microscopic fungi 

 stand closely related to many of the diseases to which plants are subject, it 

 would be well if horticulturists knew more of their characteristics ; the condi- 

 tions, favorable or otherwise, to their growth and development ; as it might enable 

 them, sometimes at least, to guard against their insidious attacks. Many plants 

 seem to have one or more parasites peculiar to themselves, which, if not actually 

 living at their expense, only bide their time, or are conditionally restrained from 

 entering upon a conflict too often resulting in much harm being done, if not 

 totally destroying them. As a proof of this, we need only call to mind how 

 much grape-vines suffered from Oidiuni Tuckerii some years ago, and the potato 

 from Botrytis infesteus. 



And now, since these pestiferous visitants have become greatly less destruc- 

 tive to these plants, the verbena is the victim of one or other of their confed- 

 erates, which threatens sooner or later, if not restrained, to render it unfit to 

 occupy the place it has so long held without a rival or successful competitor. 



In reference to the cause of the disease, we have assumed it to be the work 



VOL V. 21 l6l 



