Ch. Ill, 10] PLANTS WITHOUT CHLOROPHYLL 



87 



which are likewise half parasitic upon the roots of other 

 plants, as in case of our wild Purple Gerardia. 



Insect-catching plants do not belong among parasites, 

 because they all make their own food. The insectivorous 



Fig. 62. — The mycelium (threads ramifying in the ground) and 

 sporophores (above the surface) of a small Puff-ball ; x 5. 



habit is connected only with the acquisition of nitrogen 

 compounds, as will later appear. 



Finally, there is one other very distinct method of plant 

 nutrition. Certain Bacteria which live in the soil have 

 power to make their own food from carbon dioxide and water 

 entirely without sunlight, the necessary energy for the pro- 

 being derived from chemical energy set free by the 

 oxidation of substances in the soil. The process is thus 

 naturally designated chemosynthesis in distinction from 

 photosynthesis. While occurring at present, so far as known, 

 in only one group of Bacteria, the method has great interest 

 for the reason that it suggests a way in which plants may 

 have made their food in the far-distant times before chloro- 



