80 SIR DIETRICH BRANDIS ON THE 
(P1. 12. fig. 20). Groups of similar cells are often found near the edge of the leaf between 
the band of sclerenchymatous fibres and the first longitudinal nerve: Dendrocalamus 
giganteus (Pl. 12. fig. 14). Here and on both sides of the midrib these masses of thin- 
walled colourless cells occupy the place of the apparent cavities: Dendrocalamus strictus 
(Pl. 12. fig. 19). The idea that there is some analogy between these two tissues would 
seem to be supported by the fact that on a transverse section the apparent cavities in 
some cases appear to consist of cells other than the flat thin-walled cells described 
above. 
Volkens, in his important work ‘Die Flora der Aegyptisch-Arabischen Wiiste,’ 
describes a tissue of thin-walled colourless cells peculiar to those species which have 
the chlorophyll parenchyma arranged in rings around the vascular bundles (Panicum 
turgidum, Pennisetum | dichotomum, Sporobolus spicatus, Cynodon Dactylon, and 
Eragrostis cynosuroides). These thin-walled colourless cells, which are a continuation 
of the bulliform cells of the upper epidermis and which separate the cylinders of 
chlorophyll parenchyma, Volkens correctly designates as water-cells. A tissue of this 
character L have not been able to find in Bamboos, but it seems possible that the groups 
of thin-walled cells here described, as well as the fiat thin-walled cells which fill the 
apparent cavities, may, under certain circumstances, serve for the storage of water. 
EPIDERMIS. 
The epidermis of Bamboo leaves is remarkably uniform. Apart from the bulliform 
cells of the upper, both the upper and lower epidermis consist of two classes : firstly, 
elongated, usually linear cells, the walls of which are strongly undulated ; secondly, 
short cells, single or in pairs, which alternate with the elongated cells. I have not 
found any Bamboos with the walls of the long epidermis-cells in straight lines, such as 
are often found in other Grasses, e. g. Pleuropogon, Holm, in Bot. Gaz. xvi. (1891) t. 24. 
fig. 9. The short cells (* Kurzzellen," Grob; “ Zwergzellen,” Güntz) are more or less 
transversely rectangular, the ends generally rounded. Of the numerous other shapes 
described by Grob, I have only found those which he calls Saddle-cells. In the bands 
which lie over the sclerenchy matous fibres the short cells are frequently larger (PL 11. 
fig. 9, Bambusa vulgaris). Of both the upper and lower epidermis-cells the outer wall is 
considerably thicker than the side-walls, and on the lower epidermis there are, as à rule, | 
numerous mostly solid protuberances of the outer wall (blunt, fig. 15, Dendrocalamus — — 
Hamiltonii; pointed, fig. 7, Phyllostachys bambusoides), which on a surface view appear as 2 
circles (Pl. 12. fig. 28, Melocanna bambusoides). There are hairs of several kinds, mostly | 
on the lower, rarely on the upper surface. The principal kinds are short hairs, blunt or — 
pointed (PI. 12. figs. 13, 14, 15, 18, Dendrocalamus giganteus); long stiff hairs (Pl. 11. 
tig. 7, Phyllostachys bambusoides) ; blunt soft pluricellular hairs, the upper cells of which 
generally have the walls collapsed (Pl. 13. fig. 28, Melocanna bambusoides) ; finally, long E 
soft hairs (Dendrocalamus strict us). 3 : 
The stomata are mostly on the underside, in longitudinal bands over the chlorophyll _ 
