MYCORHIZAS 



247 



Note the degeneration of the shoot of Monotropa as a result of 

 its altered nutritive relations (Fig. 125). 1 



Secure clumps of any species of Corcdlorhiza and wash away the 

 soil. The coralloid underground organs are found to show inter- 



0^-'-'- ^ ' lb™ 



Fig. 124. Longitudinal section of apical portion of mycorhiza of Corallorrhiza Ari- 

 zonica. a, a, epidermis, m, m, mycelial layer of fungus, b, b, cortical region of- 

 branch in which organs of interchange of the fungus are formed, c, stele, d, d, d, 

 secondary branches, e , scale-leaf at apex of branch. 



nodes, and hence are stems, the roots having been lost as a result of 

 the mycorhizal adaptation. Cut cross and longitudinal sections of 

 some of the smaller branches. Note the tubular extensions of 



A B C 



Fig. 125. Monotropa uniflora. A, longitudinal section of stele of root showing 

 vessels and contiguous phloem cells. B, transverse sections through mature and 

 young roots showing vessels. C, mass of roots from which arises a flowering shoot. 



1 MacDougal and Lloyd. The roots and mycorhizas of some of the Monotropaceae. 

 Bull. N. Y. Bot. Garden. 1 : No. 5. 419. 1900. 



