82 MICROSCOPICAL RESEARCH 



PLATE VI. 



STEM STRUCTUEE. 



Fig. 19. Longitudinal median section, of apex of Stem of Pine. 

 ' Pinus sylvestris.' Fixed with the Chromo-Osmic-Acetic 

 solution X 75 dia. Stained with Brazilin. 1. Zone of apical 

 tissue in active state of division. 2 and 3, axillary buds in 

 various stages of development. 4, primary nucleated tissue. 



Fig. 20. Transverse section, half-inch below growing point. Stem of 

 Pine X 75 dia. Stained with Aniline-picrate and Gossy- 

 pimine. Tissue fixed as above. 1. Cortical tissue formed 

 of loose cells. 2. Bast. 3. Cambiform tissue. 4, Xylem 

 elements before the beginning of secondary thickening. 



5. Primary medullary ray. 6. Primary ground tissue. 



Fig. 21. Transverse section, two inches below growing point. Stem 

 of Pine X 35 dia. Tissue fixed aaid stained as in Fig. 20. 

 1. Cortical tissue. 2, Phloem elements. 3. Cambiform 

 tissue. 4. Xylem elements, after the commencement of 

 secondary thickening. 5. Ilesin passage. 6. Central ground 

 tissue. 7. Developing branch. 



Fig. 22. E-adial longitudinal section. Stem of Pine x 35 dia. Area 

 as in Fig. 21. 1. Cortical tissue. 2. Phloem elements. 

 3. Xylem elements. 4. Primary central tissue. 5. Cambium. 



6. Developing branch. 



