410 Boeurg on the Histology and 
other respects ordinary. The guard cells slope toward each 
other, have large nuclei and thick cuticle, especially toward 
the opening. The cells in the furrows connecting the 
stomata are somewhat concave in their upper surface, have 
thicker cuticle and are denser-looking. 
The cortex shows, at irregular intervals in the subepider- 
mal layer, large rounded isolated cells with dense yellowish 
contents concentrically arranged. Long-continued soaking 
and boiling in water failed to change the appearance of these 
contents. I have not been able to find that they extend 
over more than one cell in longitudinal section. 
The hard bast forms perfectly homogeneous strands, each 
element of which appears uniform in longitudinal aspect. 
Sometimes their ends taper into each other. The bast was 
conspicuous for its impartial reaction to stain. Safranin 
and methyl green proved the best combination, as the red 
set off very sharply all wood elements against the green of 
all other parts. The hard bast alone stained red or green 
apparently without preference. 
The outstanding feature of the wood in longitudinal sec- 
tion is the large pitted vessels. They appear in cross section 
as large round elements, frequently divided by branching 
into two irregular semicircles. In longitudinal section they 
are usually much broader than the adjoining elements, and 
the cells of which they are compounded show their ends 
broken through into a single large bordered pit with the 
membrane ruptured. The lateral walls show closely packed 
very large bordered pits, in various stages of growth. Fig. 
g represents a typical cell of the pitted vessels. With a 
one-twelfth immersion lens the middle lamella is seen to 
have quite measurable thickness, as is better shown in Figs. 
to and 11. It is easily enough seen, even with the low 
power lens. 
Into these pitted vessels frequent and often very copious 
tyloses extend. These are most clearly seen when studied 
in longitudinal section in the two.Figs. 10 and 11. The 
