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to form a dense thready reticulum, then branched into radiate threads 

 whose free ends became swollen in clavate fashion. He assigned to 

 the fungus a position in the genus Actinomyces. 



Chevalier, (7 p. 124-139) examined the tubercles on the roots of 

 Myrica Gale {Gale palustris), Myrica cerifera, Myrica Carolinensis 

 {M. Pennsylvanica), and Myrica sapida var longijolia. He found them 

 on main roots, adventitious roots of subterranean branches, and on 

 subterranean stems. He described at length their general gross structure 

 and histology, the occurrence of gummy lignin in the cells attacked, and 

 called the infesting organism, Frankia Brunchorstii, previously observed 

 by Moller. 



Harshberger^^ observed the tubercles on the adventitious roots of 

 Myrica cerifera. He studied the structure of the mature tubercles from 

 dry material only which had been boiled in water and afterwards treated 

 with alcohol. He called the tubercles "mycodomatia" and claimed for 

 the infesting fungus a position closely related to the Oomycetes. 



Arzberger" investigated the root tubercles of Myrica cerifera, Myrica 

 Gale, and Comptonia asplenifolia {Myrica asplenifolia) and stated like 

 Harshberger that these structures appear on adventitious roots which 

 grow out from the lower part of the stem or from branches or stems which 

 have been covered over with leaf mold or soil for several years. He 

 described the morphology and cytology of the tubercles but his illustra- 

 tions do not show the true nature of the radiating clavate branches. He 

 favored the opinion of Shibata in placing the fungus in the genus Acti- 

 nomyces. . 



During the last three years the writer has collected and examined 

 abundant tubercle material of M. cerifera, M. Carolinensis, M. Mac- 

 farlanei, Youngken, {M. cerifera, M. Carolinensis) Youngken and Comp- 

 tonia asplenifolia at Palermo and Tuckahoe, N. J. ; of M. Carolinensis and 

 Comptonia asplenifolia at Clementon and Albion, N. J. ; of Comptonia 

 asplenifolia near Mainville, Pa.; and of M. cerifera, M. Carolinensis, 

 and M. Macfarlanei at Wildwood and Rio Grande, N. J. He has raised 

 M. cerifera seedlings bearing tubercles from seeds which he planted in 

 sandy soil in the University of Pennsylvania greenhouse. He has 

 furthermore examined tubercle material of M. Gale collected by Dr. 

 John M. Macfarlane along Trefethan Bay in Chebeague Island of Casco 

 Bay and on the southeastern part of Peak's Island in Casco Bay, Maine. 



