1918] ALLARD—NICOTIANA 183 
hereditary mechanism of the tobacco plant. The writer’s experi- 
ments show that catacorolla originating as a result of the mosaic 
disease of tobacco is not inherited. For this reason the causal 
factor is external or accidental in its nature, and does not extend 
its influence to the constitution of the germ plasm. Although it 
has not been definitely established that the primary cause of the 
mosaic diseases affecting V. Tabacum and N. glutinosa is parasitic 
Fic. 9.—Upper row: blossoms possessing 6 and 7 corolla lobes; middle row: 
blossoms with 3 and 4 corolla lobes; lower row: normal 5-lobed blossom at left, 
abnormal blossom at right.—T. 1763. 
in its nature, it is evident that the blossom abnormalities observed 
in N. Tabacum as a result of the mosaic disease are analogous in 
their origin to the abnormalities, monstrosities, galls, etc., due to 
insects, fungi, bacteria, etc. 
The development of two growing points 
In the cross Md. Mammoth (2) X Yellow Pryor (4), a number 
of young plants of the first generation were characterized by two 
