Wax-coated Epiderm. 69 



worth noticing that plants such as these have smooth 

 leaves, and are without any other of those appliances for 

 the protection of flowers from crawling animals, which 

 have either been described in former pages or have 

 yet to be described in succeeding ones. 



The epiderm of the stem is in some plants covered 

 with a coating of wax ; and there can be no possible 

 doubt but that this also can serve to hinder the ascent 

 of crawling insects, and so to protect the flowers from 

 unbidden guests. The catkins of Balix dajphyioides 

 Vni., rich in nectar, and swarming with crowds of 

 bees, are thus protected ; and their flowers, which, 

 being dioecious, can only be fecundated by xenogamy 

 (so that the visits of wingless ants would be highly 

 unwelcome), are placed beyond the reach of any creep- 

 ing animals. No sooner does one of these tread on 

 the epiderm of the catkin-bearing shoots, coated as 

 this is with wax, than down it slides, as though on 

 slippery ice, and often pays for its attempt to get at 

 the enticing nectar by tumbling to the ground from 

 a height of several metres. 



4. Access to Flowers irwpeded by Prickles. 



It is abundantly clear from the preceding remarks 

 that the viscid substances secreted by the colleters, if 

 deposited on those parts of the plant which must be 

 traversed in order to reach the flower, serve specially 



