STRUCTURE OF BAMBOO LEAVES. 85 
bulliform cells in the epidermis, no apparent cavities in the mesophyll, and no folds in 
the walls of the parenchyma-cells. 
DISTINGUISHING CHARACTERS OF BAMBOO LEAVES. 
Güntz (p. 64) justly places Bamboos in a separate class with regard to their leaf- 
structure. The points he chiefly lays stress upon are the thick-walled epidermis with 
numerous protuberances, the large cavities in the mesophyll, and the scarcity of 
water-tissue. But there are many more points in regard to which the structure of 
Bamboo leaves differs from that of the leaves of other Grasses, and they may be stated as 
follows :— 
The vernation is always convolute and the full-grown leaves are flat with a prominent 
midrib, which consists of two girders of sclerenchymatous fibres, one under the upper, 
the other under the lower epidermis, and a number of vascular bundles in two lines. 
The walls of the linear epidermis-cells are always wavy, the short cells alternating 
with them being rectangular elliptic or saddle-shaped. Stomata abundant on the lower 
epidermis over the chlorophyll parenchyma, in belts alternating with belts without 
stomata. Long hairs and short ones of different shapes and protuberances, blunt and 
pointed, on the lower epidermis. Upper epidermis generally smooth with few scattered 
stomata; hairs and protuberances in a few species only (.Melocanna bambusoides). 
Bands of bulliform cells only in the upper epidermis, alternating with longitudinal 
nerves, In full-grown leaves of most species a large portion of the bulliform cells filled 
with solid silica. : 
The longitudinal nerves have always two girders of sclerenchymatous fibres, one below 
the upper, the other below the lower epidermis. "The vascular bundles of longitudinal 
nerves have two sheaths of elongated cells, an outer parenehyma-sheath and an inner of 
thick-walled elements, the mestome-sheath. No continuous bands of sclerenchymatous 
fibres under the lower epidermis, nor, as a rule, girders of such fibres on the underside 
under the band of bulliform cells. > 
Large apparent cavities in the mesophyll between the longitudinal nerves and the 
bands of bulliform cells, which are filled by flat thin-walled cells, lying upon each other, 
like the leaves of a book. While the leaves are rolled up in bud, these flat cells are 
filled with a watery fluid and are turgid; when full-grown and spread oat flat, the walls 
collapse, leaving large intercellular spaces between the collapsed walls. 
The chlorophyll-tissue fills up the entire space between the longitudinal nerves, 
epidermis, and apparent cavities; it is never limited to cylinders around the vascular 
bundles. All chlorophyll-celis have peculiar folds in the membrane, dividing each cell 
into a number of usually incomplete cylindrical tubes. 
LEAF-STRUCTURE: BIOLOGICAL AND OTHER PECULIARITIES OF BAMBOOS. 
In Bamboos most of the principal features of their life-history are the same as in other 
Grasses, but they have certain important peculiarities, and a Bamboo forest is something 
SECOND SERIES.— BOTANY, VOL. VII. P 
