274 de Frame . — The Morphology and Anatomy of the 
vascular strands are embedded in a mass of lignified tissue (sc.), the outer 
layers of which are sclerized (sc.t.) in the stouter inflorescences. In the 
smaller axes this sclerized zone becomes reduced and finally disappears, 
and the inner ring of bundles are no longer completely embedded in fibres. 
Immediately beyond the sclerized zone is a ring of very small bundles 
(vb. 2) ; they lie at the margin of the assimilating region of the axis (a.s.). 
Below the level of insertion of the first scale leaf these small bundles join 
on to the internal ring of larger strands. The assimilating layer is com- 
posed of about four rows of small, rounded, parenchyma cells, but above 
sVlr.l 
' as 
1 
Text-fig. 22. Diagram of part of the inflorescence axis of S. binervosa. x 70. a.s. = assimi- 
lating cortex ; vb. 1 = inner ring of bundles; vb. 2 = outer ring of bundles; sc.l. *= sclerized zone; 
sc. — lignified tissue ; pli. — phloem ; xy. = xylem. The white line indicates the limit of the 
sclerized zone. 
the insertion of the scale leaf the outermost layer of these cells becomes 
palisade-like (p., Text-fig. 23, A), while in the ultimate branchlets two layers 
of palisade cells are present. 
The epidermal cells have very thick walls, especially on the outer 
surface ; the external cuticle (o.c.) is heavily developed, with a ridged outer 
surface and plugs between the cells ; a well-marked internal cuticle also 
occurs (i.c., Text-fig. 23, A). Stomata and Mettenian glands are both 
present on the inflorescence axis. 
The general structure of the inflorescence axis is the same in all the 
forms of vS. binervosa , and it is only in the broad-leaved plant that any 
noteworthy variations occur. The palisade layer of the flow T ering spikes of 
