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I. W. BAILEY 
2. The nucleo-cytoplasmic ratio may be relatively constant in ray 
initials, but varies enormously in fusiform initials. 
3. All of the cambial initials of Pinus Strobus, regardless of variations in 
size, contain the diploid number of chromosomes. 
4. Small ray initials having a capacity of 5,000-10,000 cubic microns 
may contain as large chromosomes as adjacent fusiform initials with a 
volume of 1,000,000-5,000,000 cubic microns. 
5. Fusiform initials, which frequently are several hundred times as 
long as they are wide, divide longitudinally by an extraordinary extension 
of the cell plate. 
6. The various types of cell plate formation that have been described 
by Treub, Strasburger, SchiirhofT, and the writer appear to be merely 
different phases or stages of a single general type of cytokinesis. 
7. The significance of the cambium in the investigation of various 
cytological problems, particularly of those relating to the cell plate and the 
dynamics of cytokinesis, is briefly discussed. 
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