Assimilatory Tissue of Mangrove Seedlings. 181 
length, to within half an inch from the tip of the stem. It was 
found that the surface was not completely smooth, but was slightly 
ridged. It was on these ridges that the openings were found. 
Small strips of epidermis were removed from these ridges and 
examined under the microscope. It was found that the openings 
were on small tubercles. Some of these openings were connected 
with lenticels, but others were not. After cutting many transverse 
sections one or two containing stomata were found. On double 
staining with safranin and methylene blue, the guard cells stained 
red, while the rest of the epidermal cells were blue. 
Text-fig. 9. Rhizophora, sp. Semi-diagrammatic sketch of a transverse 
section of the hypocotyl. 
In addition to the above mentioned structures it was found 
that ordinary chlorophyll containing tissue was developed. This 
was not distributed in a regular layer round the stem under the 
epidermis, but varied in thickness in different parts. Near the 
stomates or lenticels there were usually from six to eight rows of 
assimilating cells chlorenchyma, but in other parts there were 
generally only two rows. As in a complete transverse section 
there were usually four or five lenticels, it follows that the 
