The Non-Green Plants 383 



necessary. The canning, drying, and preserving industries are 

 based on methods of ehminating saprophytes. The beer, wine, 

 vinegar, and cheese industries depend upon the fermentations 

 induced by carefully cultivated saprophytes. The tarring and 

 creosoting of telegraph poles and railroad ties are made necessary 

 by the universal presence in the soil of these destructive plants. 



Among the one-celled plants there are some that can live either 

 as green autophytes or as colorless saprophytes. There are many 

 that may live either as saprophytes or as parasites. It is often 

 very difficult, therefore, to classify plants among these three 

 groups or to determine the exact sources of their food and energy. 



The non-green plants, then, include a very large number and 

 variety of plants. Autophytes are world-wide in their distri- 

 bution ; the occurrence of a species is limited only by climatic 

 and habitat conditions. Parasites are widely distributed, but 

 any species is limited by the occurrence of its particular plant 

 or animal hosts. Saprophytes occur everywhere where organic 

 matter exists. The non-green plants are not so conspicuous as 

 the green plants, but they are of overwhelming importance to 

 plants, to animals, and to man. 



REFERENCE 



Marshall, C. E. Microbiology (3d edition). P. Blakiston's Son & Co., Phila- 

 delphia; 192 1. 



