182 THE BOOK OF THE ROSE chav. 



stems. In such places, and especially on the leaves 

 which are now fallen, the mildew seeds have retired 

 to rest for the winter, and no frost or cold, drought 

 or moisture, can harm them. 



These winter places of retreat are tiny black spots, 

 only visible on the dying leaves by the aid of a 

 magnifying glass, though a higher power of the 

 microscope reveals them as round black receptacles 

 or boxes, each containing eight spores. In these 

 minute black spots on the leaves Rose mildew 

 passes its winter sleep, unhurt by all that may 

 befall, save fire or being buried deeply in the ground. 

 The sun of the following summer will burst the 

 walls of the cases, and set free the spores once 

 more. 



Collecting and destroying by fire the fallen leaves 

 is thus plainly the only mode of prevention, which 

 in most cases will probably be found impracticable, 

 but even a partial carrying out of this plan should 

 have some effect. It is impossible to say how far 

 the spores may be carried by a strong wind, but 

 probably many miles. An actual stamping out of 

 the pest is therefore, I fear, beyond our reach. 



Preventive measures consist first in the choice of 

 an open situation : in a confined place the seeds 

 floating in the wind are more apt to drop, or to be 

 carried round and round till they do attach them- 

 selves to the leaves : where there is free passage for 

 the air, the same wind that brings them will take 

 most of them farther on, and only a few will find 

 resting places. 



Against harmful seeds brought by the wind, there 

 are therefore two preventive measures : either abso- 

 lute exclusion from any wind or even air, or entire 



