Chapter XVII I. 



CARNIVOROUS PLANTS AND PARASITES. 



A typical plant, is green in colour, and it is so because 

 it possesses a quantity of a peculiar substance called plant- 

 green, or chlorophyll. This substance contains a minute 

 quantity of magnesium. By means of the energy derived 

 from light, this has the power of decomposing carbonic 

 acid gas, and, after a complicated process, of producing 

 starch or sugar. After this, by further combination with 

 salts received by means of the water absorbed by the roots, 

 all the multifarious compounds required as food by the 

 plant are well built up. 



All plants have not this plant-green, and therefore do 

 not perform these acts. The fungi, forty thousand strong 

 in species, are without it; so are isolated cases, even 

 amongst flowering plants. When this is so the habit of a 

 plant is similar to that of an animal, in so far that it is 

 dependent for its well-being on being able to absorb com- 

 pounds already formed. 



There is no rigid line between plants with plant-green 

 and without. There are all grades of intermediate con- 

 dition where it is present, but not in sufficient quantity to 

 enable the plant to do all its work, where it is partly 

 dependent on its chlorophyll and partly upon absorption. 



It is probable that normally green plants cannot absorb 

 high compounds through their roots. Though the mixing 

 of such, as manures, are of great use, they are first reduced 

 to a relatively simple condition before they can be taken 

 up. 



The first condition of departure from the normal is 

 for a plant to gain the power of absorbing the material 

 of dead animal and vegetable remains. As it gains this 

 power it ceases to construct chlorophyll, and therefore 

 ceases to be green. It may be white or any other colour 

 but green. Some orchids and the greater number of 

 fungi are in this condition. They thrive amongst rotting 

 plant remains, and assist in the breaking up of such 

 material and bringing it into use again. Plants that live 

 in this manner are called saprophytes. 



The next condition we notice is that plants may form 

 an attachment to others, and suck some of thfcir required 

 nutriment from them while still retaining the power of 



