128 THE EVOLUTIONIST AT LARGE. 



round flax ; and the third, which I have here 

 under my eyes, mainly confines its dangerous 

 attentions to gorse, clover, and thyme. All 

 of them are, of course, deadly enemies to the 

 plants they infest 



How the dodder acquired this curious 

 mode of life it is not difficult to see. By 

 descent it is a bind-weed, or wild convol- 

 vulus, and its blossoms are in the main 

 miniature convolvulus blossoms still. Now, 

 all bind-weeds, as everybody knows, are 

 climbing plants, which twine themselves 

 round stouter stems for mere physical sup- 

 port. This is in itself a half-parasitic habit, 

 because it enables the plant to dispense with 

 the trouble of making a thick and solid stem 

 for its own use. But just suppose that any 

 bind-weed, instead of merely twining, were 

 to put forth here and there little tendrils, 

 something like those of the ivy, which 

 managed somehow to grow into the bark of 

 the host, and so naturally graft themselves 

 to its tissues. In that case the plant would 



