FUNGOUS ROOT-TUBERCLES. 81 



branches arranged in an aster-like form and ultimately fill- 

 ing the entire cell. Shibata places this fungus with the genus 

 Actinomyces, thus differing from that found in the Podocar- 

 pus, Psilotum, Alnus and Elaeagnus tubercles. 



Harshberger (15) was the first to report the tuberculous 



/ 

 ata had already made some inv 



and M. rubra. He calls them m 



term 



The 



found on these roots when the stems 



rounded by shifting sand. At first the masses are relatively 



but by 



aggrega- 



tions attaining the size of a walnut are produced. The struc- 

 ture of the tubercle was studied from dry material which had 



boiled 



From 



m these he describes 



hyphomycete 



d 



forming a dense mass 



hyphae within. However, the microphotographs obtained 

 from these sections do not show the true nature of the fungus 

 and Harshberger, rather unwarrantedly, claims for the fun- 

 mis a position closelv related to the Oomycetes. 



gathered in November and December 

 the Missouri Botanical Garden. Myric 

 folia were also examined 



Myrica cerif 



material as the above named species. These 



grow out from 



the lower part of the stem, or from branches or stems which 

 have been covered over with leaf mould or soil for several 

 years. This fact agrees with the observations of Harshber- 

 ger (14), who found these growths on stems which were 

 surrounded by sand in localities where sand dunes are 

 formed. Other roots have a few tubercles which, howe 



ad 



ventitious roots, nor are they as abundant as the tubercles 

 found on Alnus, Ceanothus and Elaeagnus. 

 The tubercles are usually found in masses varying in size 



