436 The Physiology of Plants BOOK in 



plants, and their bearing on nitrogen supply. In many 

 cases filamentous fungi were found associated with roots of 

 various trees and shrubs, in some cases being entirely in- 

 ternal, in others forming a feltwork over the exterior. These 

 associations became known as endotrophic and ectotrophic 

 mycorhiza respectively, the term being introduced by Frank 

 in 1888. 



Ectotrophic mycorrhiza was discovered in 1881 by 

 Kamienski, in Monotropa, and was observed to exist in a 

 large number of forest trees by Frank in 1887. Numerous 

 examples have been discovered more recently. Endotrophic 

 mycorrhiza was known long ago by Schleiden, who observed 

 it in Neottia. Its wide distribution, especially among plants 

 of the Natural Orders Ericaceae and Epacridaceae, was 

 pointed out by Frank in 1887 and by Schlicht in 1889. The 

 way in which the fungus penetrates Neottia and lives in the 

 interior of its cortical cells was investigated fully by Magnus 

 in 1900. Stahl in the same year made very comprehensive 

 researches into these relationships. 



The fact, known long ago, that many fungi live at the 

 expense of non-living organic food, while others infest the 

 living body, led to their being classed into saprophytes 

 and parasites. A certain power of adaptability possessed 

 by them was discovered in 1884 by De Bary. He found 

 that by appropriate methods of culture some of the sapro- 

 phytes can be made to infect living organisms. He 

 therefore introduced the terms facultative and obligate 

 parasites to indicate the possession of this property or its 

 absence. 



Marshall Ward, in 1899, introduced the term metabiosis 

 to indicate the condition in which one of the higher organ- 

 isms is infested with two fungi, the first of which, a parasite, 

 kills the tissues of the host, and the second lives on the 

 dead material resulting. 



The investigations that were conducted on the so-called 



