ON THE PINES OF AUSTRALIA, 149 
of a leaf of a Pinus (a leaf taken simply as typical of the 
Family) or a phanerogamous leaf in general. 
The vascular bundle in Pinus is fairly evenly surrounded 
by parenchymatous tissue, whilst in Callitris such is not 
the case, for at the basal junction of the concrescences the 
meristele comes very closely to the cuticle or the outside 
air. However, in Pinus the vascular bundle forms the 
central column around which regular leaf tissue is sustained, 
and so in Callitris the ultimate portion of the branchlet 
forms the central vascular bundles supporting adnate leaf 
sections which collectively appear to form one whole leaf 
body, or at least that is our interpretation of this part of 
the tree for descriptive purposes. 
In Pinus the vascular bundle is either simple or divided, 
and regarding then a section (supra) of Callitris as repre- 
senting a terminal leaf, it is also found that the central 
column is simple or divided, but mostly the latter—three 
bundles predominating, although as many as six have been 
found. Taking then a three divided vascular bundle 
section, with three adnate cross sections attached, for 
description, and describing from the centre outwards, we 
find that each division of the bundle is wedge shaped, being 
separated by central and medullary thin-walled pith cells. 
The central xylem is succeeded by an orientated phloem, 
the relative position of these elements therefore is in accord 
with their final desposition in maturity of stem and branches. 
Subsiduary to these will be found near the base of each 
concrescence division and below the oil gland a small bundle 
trace of the true decurrent leaf with the phloem also 
orientated. These and the central bundles might thus be 
considered as corresponding to the midrib and veins of 
an ordinary bilateral leaf. 
The xylem and phloem cells call for no special remark as 
they conform to the usual characters of such found in the 
