128 STINGING AND DEAD NETTLES. [CHAP. 



two species, however, are nearly allied to one another, 

 and I prefer, therefore, to take as an example of 

 mimicry the Stinging-nettle ( Urtica) and the common 

 Dead-nettle (Lamium albittn). These two species 

 belong to totally different families ; the flowers are 

 altogether unlike, but the general habit and the 

 form of the leaves are extremely similar. 



How close the similarity is may be seen by the 

 following illustration (Fig. 79), taken from an excellent 



FIG. 79. Laiiiinm and Urtica. 



photograph made for me by Mr. Harman, of Bromley. 

 The plants on the left are true Stinging-nettles; 

 those on the right are the white Dead-nettle, one of 

 which is in flower. So close was the resemblance 

 that, after getting the photograph, I went back to the 

 spot on which they were growing to assure myself 

 that there was no mistake. It cannot be doubted 

 that the true Nettle is protected by its power of sting- 

 ing ; and, that being so, it is scarcely less clear that 

 the Dead-nettle must be protected by its likeness to 



