THE ROOT 179 
In the modern rotation of crops, plant growers plough under the 
leguminous crops or their nodule-producing roots which decay 
and enrich the soil with ample nitrogenous material to supply the 
next season’s crop of nitrogen-consuming plants, such as cereals, 
cabbage, potatoes, etc. 
Many strains of Pseudomonas radicola exist, one for every kind 
of leguminous crop. Cultures of many of these, such as “‘Nitro- 
Germ,” etc. are now obtainable from the drug trade. 
Saeee 
Fic. 111.—Tubercular clusters on underground stem and roots of a Bayberry; 
Myrica Macfarlanci, observed by the author at North Wildwood, N. J., Jan. 31, 
1915. 
Myrica TuBeRCLES.—The writer has found tubercles on 
Myrica cerifera, Myrica Caroliniensis and Myrica Macfarlanei seedling 
primary roots of 5 to 6 months’ growth, and from thence onward 
on the secondary roots inserted on the hypocotyl axis, on nearly 
all the adventitious roots of subterranean branches and on the 
subterranean branches of Myrica certfera, M. Caroliniensis, M. Gale, 
M. Macfarlanei, and Comptonia asplenifolia. The inciting organism 
has been isolated by him in pure culture, according to Koch’s 
postulates, and named Actinomyces Myricarum Youngken. 
