CHAPTER XIII 



CLASSIFICATION OF PLANTS ACCORDINO TO THEIR 

 MODE OF NUTRITION 



1. Green plants. 



2. Non-green plants — 



(a) Saprophytes, 

 (6) Parasites. 



3. Insectivorous plants. 



4. Symbiotic plants. 



1. Green Plants. — These plants are autotrophic, or self- 

 nourishing. They are able, by means of the chlorophyll 

 present in their green cells, to form, during sunlight, carbo- 

 hydrate from carbonic acid gas. The nitrogen required 

 for the synthesis of proteins is obtained, not from the air, 

 but from mineral salts present in the soil. 



2. Non-Green Plants.— These, not possessing chloro- 

 phyll, are imable to make carbohydrate for themselves. 

 They must therefore obtain it from sources outside their 

 own bodies — i.e., they are heterotrophic. Not needing 

 light for photosynthesis, they generally Kve in darkness. 

 According to the nature of the source from which they 

 obtain their food, non-green plants are divided into two 

 groups — Saprophytes and Parasites. 



(a) Saprophytes (Gr. sapros, rotten). — These are colour- 

 less — that is, non-green — plants which obtain their carbo- 

 hydrate from the rotting products of vegetable or animal 

 remains. Animal excrement, since it contains organic 

 material exposed to decay, is a minor source. The 

 majority of fungi are saprophj^es ; not being able to make 

 sugar for themselves, they get it from the humus in 

 which they grow. Soil-bacteria are saprophytes, and so 

 are all those bacteria which initiate putrefaction or bring 



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