152 R. T. BAKER AND H. G. SMITH. 
interlock with those on the opposite leaf termination, like 
teeth of a cog-wheel and becoming ligneous, hold the cells 
together in a very firm grasp during the fertilisation and 
maturing of the ovules. The guard cells of. the stomata 
call for little comment, being of the usual shape of such, 
relatively however to the size of the air cavities, they are 
larger than obtain in most phanerogams. 
With the exception of one or two rarely occurring on the 
lower dorsal surface, stomata are only to be found on the 
ventral concave sides of the concrescence, where they 
occur in longitudinal irregular rows the whole extent of 
the ventral face of the concrescence as shown in Fig. 15. 
A few sometimes occur on the appressed lower part of the 
free portion of the concrescence. Being thus placed, they 
have the full advantage of the whole leaf substance as a 
protection against solar rays, rain or cold, and perhaps a 
secondary protective provision is provided as the edges of 
the individual leaf sections have the power of closing the 
entrance to the cavity when these adverse aerial conditions 
prevail, for the sections examined seem to support this 
theory, as the apertures are sometimes found open as well 
as closed, vide Figures. This of course can only be verified 
by assiduous field observations, but nevertheless we are at 
present under the impression that this may be one of the 
reasons for the decurrency in Conifer leaves, i.e., that the 
maximum amount of protection for the transpiratory 
surface is obtained by the minimum amount of leaf move- 
ment. 
The specific name was given by Brown on account of 
the bloom of the leaves. Francis Darwin,’ states, ‘* the 
position of the stomata in Conifers is very generally indi- 
cated by the existence of a glaucous bloom,”’’ but this is 
not so in the case of this species of Callitris, for the stomata 
1 Journ. Linn. Soc., Bot. ,vol. xx11, 1886, p. 99. 
