283 
Festuca rubra near Cardiff. 
Seen in transverse section the cells of the mesophyll radiate 
outwards from the vascular bundles, hut in longitudinal section the 
palisade cells can be distinguished as being regular and compact, 
each cell directed slightly obliquely upwards from the bundle 
towards the outer epidermis of the lamina. 
5. The Cauline Leaf. 
The lamina of the cauline leaf has a comparatively short life, 
but is nevertheless a specialised structure as regards drought 
resistance. When open it is more or less flat and stands out 
practically at right-angles to the axis. A transverse section of the 
highest lamina on the axis of grandijlora showed nine longitudinal 
ridges along the upper surface, and in the furrows there are 
specialised “ motor” cells, larger than the rest, which are scarcely 
raised above the general level of the surface. The hairs on the 
surface are more numerous and longer than those of the radical 
leaves. Groups of sclerenchyma occur below both upper and 
lower surfaces, in some cases in contact with the vascular bundles. 
Stomata are numerous on the upper epidermis. In tenuifolia the 
cauline lamina has only five to seven ridges, and is poorer in 
sclerenchyma. 
6 . Rhachillce. 
The lowest rhachilla is subtended by a small bract, whose base 
encircles the axis, but whose upper part is free and crescent¬ 
shaped in section (Fig. 13). It is composed of parenchymatous cells 
whose somewhat thickened walls are pierced by numerous pits. 
These cells are continued into the cortex of the axis at the node. 
At the higher nodes there is no obvious bract, but the cortical cells 
are developed in the same way. 
The morphology of the paired rhachillae is evident from a study 
of serial transverse and of longitudinal sections through the node. 
The bract is a simple structure ; it is present as a slight ridge of 
tissue around the stem just below the insertion of the paired 
rhachillae, highest on the side from which these are given off, 
lowest on the opposite side. It does not suggest any fusion, so that 
there is every reason to believe that it subtends a single primary 
branch, which is the larger of the pair of rhachillae. From this is given 
off almost immediately a weaker secondary branch, the smaller 
member of the pair. There is no trace of a bracteole. 
This view is supported by tracing the various vascular bundles 
from the axis below the node into the rhachillae. The vascular 
