104 Chapters in Modern Botany CHAP. 



much importance to it, but it is far otherwise. What is 

 true of Melampyrum is true of several hundred species of 

 plants, especially of the orders Santalaceas and Rhinan- 

 thaceae. Thus the louseworts (Pedicularis) have very long 

 surface-roots which attach themselves to the fibrous roots of 

 the grasses and other plants of pastures and meadows. 

 The length of the roots is in part explained, as Kerner 

 points out, by the fact that most species of Pedicularis 

 persist from year to year. For when a root has fixed itself 

 to that of an adjacent annual, and that has died, it becomes 

 necessary for the parasitic root to shift its anchorage and 

 to find another farther on. This case of Pedicularis is 

 further interesting because the root-hairs which are borne 

 by the roots of most plants are here absent, except at those 

 points where parasitic attachment is effected ; not but that 

 the skin of the root may without root-hairs absorb water 

 and salts and the products of decaying vegetable-mould. 



Of the Alpine Bartsia (JB. alpina), Kerner states that 

 some of the roots are parasitic, while others are adapted for 

 absorbing humus ; and among the same group of root- 

 parasites we have also to include the odd -flowered and 

 fruited yellow - rattles (Rhinanthus crista-galli), and even 

 the pretty Eyebright or Euphrasy {Euphrasia officinalis) of 

 our moorland pastures and roadsides. 



The root-parasites are often blamed for spoiling pastures, 

 and even the milk of the cattle that graze there. They 

 certainly often occur in great abundance, and hence must 

 to some extent impoverish the plants whose roots they 

 suck ; as yet, however, there is no definite evidence of 

 appreciable damage done. 



One wonders what constitutional peculiarity distinguishes 

 the members of these two orders (Rhinanthaceae and 

 Santalaceae), so many members of which have this strange 

 habit of root-parasitism. Some hints of an answer have 



