FLOWERING PARASITES 185 



one should say correlatively, retained their 

 leaves, and all the complexity of structure 

 which, as we have seen, the presence of the 

 green leaf entails. 



The parasitic habit has appeared inde- 

 pendently in a number of other families of 

 flowering plants. In some of them it is char- 

 acteristic of practically all the members, 

 just as in the Loranthaceae mentioned above. 

 As a matter of fact, in very many of the 

 larger natural orders or families we also find 

 species which have more or less broken away 

 from the ranks of typical green plants in con- 

 nection with their assumption of saprophytic 

 or parasitic habits. Sometimes we can 

 construct, within the limits of nearly related 

 groups, all the stages, starting from a sort 

 of dalliance with robbery which is hardly 

 betrayed by any essential structural change, 

 but culminating in species which, so far as 

 their vegetative structure is concerned, have 

 lost all resemblance to the forms of higher 

 plants. 



Thus in the alliance or family to which 

 the snapdragon belongs, the familiar little 

 Eye-bright (Euphrasia), abundant on grassy 

 downs, the pink Lousewort (Pedicularis) of 

 the marshes, and the yellow Cow-wheat 

 (Melampyrum) of the woods, all have begun 

 to supplement the legitimate stock of food 

 which they manufacture for themselves by 

 stealing from adjacent plants. This they are 

 enabled to do owing to the ability they possess 



