Interspecific Transmission of Mosaic Diseases of Plants 33 



of two, which may prove to be identical. The differences between the 

 mosaics are shown by the species they are able to attack, and by the 

 different symptoms produced by them when inoculated on the same species. 

 They apparently differ also in the ease of inoculation. 



Unusual necrotic symptoms not resembling those generally considered 

 characteristic of mosaics, were produced by mosaic A on Solatium tuber- 

 osum and Nicotiana rustica. 



The suscept ranges of the mosaics, in so far as they were determined, 

 were as follows: 



Mosaic A : Lycopersicon esculentum, Martynia louisiana, Nicotiana rus- 

 tica, N. Tabacum, Physalis heterophylla, P. subglabrata, Solanum aculea- 

 tissimum, S. atropurpureum, S. carolinense, S. nigrum, S. tuberosum. 



Mosaic B : Datura meteloides, D. Stramonium, Lycopersicon esculentum, 

 Nicandra Physalodes, Nicotiana glutinosa, Solarium aculeatissimum, S. 

 atropurpureum, S. carolinense, S. tuberosum. 



Mosaic C : Datura meteloides, D. Stramonium. 



Mosaic D : Nicotiana glutinosa. 



Mosaic E : Phytolacca decandra. 



Mosaic F : Rumex obtusifolius. 



Mosaic G : Phaseolus vulgaris. 



Mosaic H : Echinocystis lobata, Nicandra Physalodes, Nicotiana gluti- 

 nosa. 



Two mosaics were produced on Datura meteloides, D. Stramonium, 

 Lycopersicon esculentum, Nicandra Physalodes, Solanum aculeatissimum, 

 S. atropurpureum, S. carolinense, and S. tuberosum. Three mosaics were 

 produced on Nicotiana glutinosa. 



Some of the data appear to indicate that potatoes which are apparently 

 healthy,- carry a virus which is able to produce mosaic symptoms when 

 transferred to other species. 



