compared with other genera of Cycadeae. 607 
Structure of the Vascular Zones. 
As seen in transverse section, the xylem of the normal ring 
is divided up, as in other Cycads already described, into 
narrow segments consisting of from one to three or four 
rows of elements in breadth, these being separated by 
medullary rays one or more cells broad. These segments 
of the xylem taper towards their inner margin where they 
abut on the pith. They appear usually to be arranged in 
groups with wider medullary rays separating such groups. 
As the different parts of the xylem, as well as of the 
phloem, are not all cut through in an equally accurate 
transverse direction, but are, on the contrary, often very 
obliquely sectioned, some of the vascular segments must 
depart considerably from the normal vertical course, and 
this was seen in longitudinal sections to be the case in nearly 
every part of the stem. 
The phloem, in transverse section, appears to be composed 
of fairly regular rows, 2-4 cells broad, of sclerenchymatous 
elements, and of thin-walled small-celled tissue, the whole 
being divided up into segments, as is the xylem, by the 
medullary rays. On the outer side are seen the crushed 
remains of the primary phloem. On the inner side the 
cambium, forming a conspicuous zone, separates the secondary 
phloem from the xylem. Large idioblasts or stone-cells 
occur everywhere scattered about amongst the cells of the 
rows and in the medullary rays. 
The xylem and phloem are of almost equal thickness. 
They are moreover, when observed under a low power, by 
no means easy to distinguish the one from the other, the 
lignified fibrous elements of the phloem being readily mis- 
taken for tracheides, 
A radial longitudinal section shows the wood to be of the 
usual Cycadean character ; and owing to the tangentially- 
curved course of the tracheidal bands, the appearance is given, 
in most sections, of alternating zones of tracheides and ray- 
parenchyma. The protoxylem has completely disappeared 
