PARASITES 



181 



rattle and of the Lousewort to realise their social habit. These 



semi-parasitic plants do not injure their hosts to at all the same 



extent as the true parasites. These green-leaved parasites are very 



social plants ; hundreds and thousands 



of specimens are found close together. 



The Eyebright is so prolific in moun- 



tainous districts that when its flowers 



are open, regular white lines seem to 



stretch across the pastures. It is para- 



sitic on the roots of grasses, and is called 



in Germany " Milchdieb," (milk thief), 



from the popular belief that it injures 



the grass and makes the milk less good. 



The Rattles have long roots which grow 



horizontally, not vertically, in the upper 



layers of soil, seeking the root of some 



grass or sedge on which to fasten their 



suckers. Should the Rattle not be able 



to find a host as the plant on which it 



preys is called the growth of the root 



ceases. 



SAPROPHYTES. Some Flowering _. J ,-,. . 



FIG. 53. Red Rattle (Pedicularts 



Plants growing in woods derive their paiustris). 



food either entirely, or partly, from 

 the humus formed by the leaves of the 

 trees, and therefore may be said to depend 

 on the tree for nourishment. The En- 

 chanter's Nightshade is an instance of a 

 plant with green leaves which also feeds 

 on the humus. Others, like the Bird's- 

 Nest and the Coral- Root Orchids, have 

 colourless leaves and feed entirely on the 

 humus. The Bird's-Nest is widely dis- 

 tributed in pine woods and in those con- 

 sisting of deciduous trees. Both stem and 



FIG. 54.-Eyebright (E- flowers are of a n ht browncolour. The roots 

 offidnaiis). 



interlace and bear a certain resemblance 



