504 Shove.—On the Structure of the 
In Fig. 3, a longitudinal section taken a little to one side 
of the middle line of the leaf, the outermost stipule (s) is 
continuous with the tissues of the leaf-base. The wrapping 
of one stipule (s) over the other (s') is seen also in Fig. 4, 
which is a transverse section of the leaf shown in Fig. 3 taken 
along the line AB. The space between the stipules is filled 
up with ramenta. 
The leaves attain their maximum size about the middle 
of the stem; here the cicatrix left by the fallen petiole 
measures from 5 to 6 cms. in diameter. Even among these, 
however, a small leaf-base not infrequently occurs. 
The surface of the stipules and of the swollen leaf-base is 
covered with numerous scars (Fig. 1, l), somewhat lighter in 
colour than the other peripheral tissues and slightly depressed 
below the surface. The scars are oval in outline on the 
stipules and the sides of the leaf-base, but circular on the 
convex rounded portion; on the petiole itself they form 
narrow short streaks or spots. These pits, the so-called 
lenticels, are small on the petiole, but may attain a diameter 
of from 1 to i| cms. on the leaf-base. 
In the older leaves the surface of separation of the petiole 
from the leaf-base is clean-cut, and in it the ends of the 
steles that have been snapped asunder by the breaking away 
of the petiole are clearly seen, arranged more or less in 
circles. 
In the younger leaves the lower part of the petiole still 
remains attached to the base, and its upper end is jagged and 
broken, where the rest of the leaf was artificially removed. 
Finally, in the youngest leaves the petiole still remains 
circinately coiled, and is completely enclosed by the two 
overlapping stipules, which are covered with numerous 
ramenta. 
These ramenta are not found on the old leaf-bases., the 
surface of which is irregularly corrugated, firm in texture, 
and brownish-black in colour. 
