198 



HIGHER PLANTS AND SOIL MICROORGANISMS 



fungus, or endophyte, when high concentrations of sugar were 

 furnished in the early stages of their development. Subsequent 

 to growth of the roots, the plants'appear to be able to develop 



Fig. 76. — Median longitudinal section of orchid seedling one month after 



infection by the mycorrhiza fungus; twisted fungal hyphae appear in many of 



the cells (from Bernard). 



as other green plants, obtaining their energy from the sunlight and 

 mineral substances from the soil. With certain non-chlorophyllous 

 plants, as a few species of orchids and Monotropa, or the Indian 

 pipe, mycorrhiza fungi play an even more indispensable role. 



