121 



are able to mature their seeds, they are frequently intarnally infected by 

 the mycelium of the fungus and thus serve to carry the disease from sea- 

 son to season. 1 , 2 , 3 



Rusts. 

 It: is now believed by some pathologists that certain species of Pue- 

 cinia are perpetuated by means of the seed of the host plant. Eriksson, 

 after long investigation, came to believe that the fungus exists in the seed 

 in a mycoplasmic form which can only with difficulty be detected from the 

 protoplasm of the cells in the seed. As the plant grows, the mycoplasm 

 spreads from cell to cell, finally appearing as mycelium in the intercellular 

 spaces. He believes that the rust may be inherited from preceding crops 

 by means of this mycoplasm. 4 It is generally believed that the facts do 

 not warrant the acceptance of this theory. Bolley thinks that infection 

 may take place from spores inside the seed itself. He found both uredo 

 and teleutospores of Puccinia graminis borne in spore beds just below the 

 bran layer of wheat and also found plenty of rust-mycelium within the 

 seed. 5 Eriksson reports seed infection with Puccinia graminis and P. 

 glumarum in wheat, oats, and barley, and P. dispersa on rye. Noack re- 

 ports a case from Cooke of carnations being affected by rust which must 

 have been caused by seed infection and he himself observed an incident 

 of celery-rust that was likewise caused by infection from the seed. 



Anthracnose of Tomato. 

 Colletotrichum lycopercici Ches. on Lycopersicum esculentum. 7 



Bacteriosis, or Bacterial Blight of Beans. 



Bacterium phaseoli Sm. on Phaseolus vulgare* 



This disease affects the stems, leaves, and pods (Fig. 7) of various 



field and garden beans, including limas. It spreads through the pods into 



the seeds, where the bacteria live through the winter, thus carrying the 



disease from season to season. 



1. Bolley, H. L., Flax Wilt and Flax Sick Soils. N. D. Bui. 50, 1901. 



2. Bolley, H. L., Flax and Flax Seed Selection. N. D. Bui. 55, 1903. 



3. Bolley, H. L., Flax Culture. N. D. Bui. 71, 1906. 



i. Eriksson, J., A General Review of the Principal Results of Swedish Research 

 on Grain Rusts. Bot. Gaz. XXV; 26; 1898. 



5. Bolley & Pritchard, Rust Problems, etc. N. D. Bui. 68: 1906. 



6. Noack, Fritz, Die Verschlepping von Pflanzenkrankheiten durch Samereien. 

 Zeitsch. land. u. ver Hersen. 1893. No. 20, pp. 161-2. Trans, by Prof. H. H. Whetzel. 



7. Harvey, F. L., Tomato Anthracnose. Me. State Coll.iAnn. Rept. 1893. Part II, 

 p. 152. 



" ' 8. Whetzel, H. H., Some Diseases of Beans. Cor. Exp.lSta. Bui. 239, 1906. 



