THE NUTKITKiN ( iF I'LAXTS 157 



119. Saprophytes. — In the case of saprophytes dead hodies 

 or body products are attacked, and sooner or later all or- 

 ganic matter is attacked and decomposed by them. The de- 

 composition is a result of the nutritive processes of plants 

 without chlorojjhyll, and were it not for them " the wliole sni-- 

 face of the earth would be covered with a thick deposit of 

 the M,nimal and plant remains of the past thousamls of years."' 



The green plants, therefore, are the manufacturers of or- 

 ganic material, producing far more than they can use, while 

 the plants without chlorophyll are the destroyers of organic 

 material. The chief destroyers are the Bacteria and ordi- 

 nary Fungi, l)ut some of the higher plants have also adopt- 

 ed this method of ol)tainiiig food. ^lany ordinary green 

 plants have the saprophytic habit of absorbing organic ma- 

 terial from rich humus soil; and many orchids and heaths 

 are i^arasitic, attaching their subterranean parts to those of 

 other plants, becoming what are called " root parasites." 



120. Parasites, — Certain plants without chlorophyll are 

 not content to obtain organic material from dead bodies, 

 but attack living ones. As in the case of saprophytes, the 

 vast majority of plants which have formed this haljit are 

 Bacteria and ordinary Fungi. Parasites are not only modi- 

 fied in structure in consequence of the alisenco of chloro- 

 phyll, but they have developed means of penetrating tlieir 

 hosts. ^lany of them have also cultivated a very selective 

 habit, restricting themselves to certain plants or animals, 

 or even to certain organs. 



The parasitic habit has also been developed by some of 

 the higher plants, sometimes completely, sometimes par- 

 tially. Doddei', for example, is completely parasitic at 

 maturity (Fig. 118), while mistletoe is only partially so, 

 doing chlorophyll work an<l als(.) a.bsorbing from the tree 

 into which it has sent its haustoria. 



That saprophytism and parasitism are liotb habits grad- 

 ually accjuired is inferred from the nund)er of green plants 

 which have developed them more or less, as a sup]ilenient to 



