246 ROMANCE OF LOW LIFE AMONGST PLANTS. 



as the fly-moulds are in possession of a process of 

 sexual reproduction by conjugation, we have justified 

 a reference to them here. How much more justified 

 do we feel in having made known the various methods 

 by which these simple organisms reproduce and ex- 

 tend themselves amongst a very destructive class of 

 noxious insects ; and, on the romantic side, to suggest, 

 if we can do no more, the inoculation of plant-lice 

 with a potent epidemic, with a view to their destruc- 

 tion, and once more corroborate the axiom that 

 " Knowledge is power." 



Trimorphic Uredines. 



Persons who dwell in the country, or are addicted 

 to spending much of their time in rural districts, 

 become acquainted with phenomena in plant life to 

 which citizens are strangers. Certain diseases of the 

 flowering plants, wayside weeds, are familiar to coun- 

 try life by the snuffy-like powder with which the green 

 leaves are sprinkled during summer, which even the 

 uninitiated regard as manifestations of disease, and are 

 apt to distinguish as "rust." As an example of this 

 kind of parasite we will take a common wayside weed 

 called "nipplewort," or botanically, Lapsana conimimis. 

 If the leaves of this plant are examined in March or 

 April, when the plants are still young, some of them 

 will be seen to present irregular purplish spots, per- 

 haps half an inch in diameter on either surface of the 

 leaf, and readily distinguishable by the naked eye. 

 Very soon after their appearance these spots will ex- 

 hibit, scattered over their surface, whitish dots elevated 

 above the purple substratum, which, by the aid of a 



