/ 



FUNGOUS BOOT-TUBERCLES. 89 



■ 



established itself inside the cell. In Ceanothus, however, 



the growth 



mass enlarges, the cell walls are dissolved and 



more 



may 



minute structure of the fungus of each of th( 

 mvcelium of that in Ceanothus measures from 



and has branches 



intervals. 



but .2 to .5 /x 



much 



duced on both 



same size, and the breakin 



subsequent fate does not differ very much. 



The nuclei of the fungus in Elaeagnus are very much 

 smaller and more numerous than those found in Cearfothus 

 and Myrica, yet they are quite distinctly differentiated from 

 the cytoplasm with the safranin, a result difficult to obtain 

 with that of Ceanothus by using similar methods. Accurate 

 measurements could not be made because none of the nuclei 

 are more than a small fraction of a micron in diameter. 



In both forms the content of the sporanges breaks up into 

 several segments so that frequently four or more can be 



umber 



smaller 



be 





conditions which Shibata (38) points out in the fungu 



number 



♦ 



in one sporange. These facts cannot be found in the fungus 

 of Myrica tubercles. No differentiation of the content in 

 the vesicles takes place even after the nuclei have wandered 

 into them. This and other features of this unicellular fungus 

 indicate that it is entirely different from that in Ceanothus 

 and Elaeagnus. 



mbiosis 



attributed 



mentioned. If the 



more closelv associated 



tubercle, Stahl's views, that it absorbs mineral salts and 

 changes them into nitrogenous compounds for the use of the 

 plant, might offer some solution of the problem involved. 

 This mav be true among the ectotrophic mycorrhiza, but in 



