Page:The Journal of Indian Botany.djvu/58

 sclerenchymatous pericycle. The pericycle consist of large groups of stone-cells separated by the chlorophyll containing parenchyma of the cortex. The wood (fig. 2) is composed of large xylem bundles separat- ed by broad medullary rays which come into contact with the chloro- phyll containing parenchyma of the cortex. Vessels are large and have simple perforations. Groups of cells, resembling bast fibres, are present on the inner side of the xylem. Inter fascicular wood-prosen- chyma is not developed. The endodermis is not differentiated. The soft bast occurs in groups on the outer side of the xylem, separated by medullary rays. The pith is composed of thick-walled cells and some of these contain small clusters of acicular crystals of oxalate of lime.

Woody. — The middle tissue of the mesophyll composed of large colourless polygonal cells with water-storage function. Neither sur- face of the leaf grooved. Axis not furrowed. Assimilatory tissue of the axis composed of short palisade cells. Sclerenchymatous pericycle in the form of a few scattered bast fibres. Vascular ring broad with vessels uniformly distributed in incomplete rows and more numerous in the lower half.

Farsetia macrantha Blatt and Hall, Flos. 4, 7, 8.Herbaceous.— Middle tissue of the mesophyll composed of chlorophyll containing horizontally elongated cells with assimilatory function. Lower sur- face of the leaf characterised by ridges and furrows. Axis furrowed. Assimilatory tissue of the axis formed of an outer portion of palisade cells and of an inner portion of chlorenchyma. Sclerenchymatous pericycle in the form of closely placed large groups of bast fibres. Vascular ring undulate and composed of small vascular bundles connected by narrow strands of interfascicular wood prosenchyma with cells resembling stone cells.

Structure of the Leaf. Epidermis consists of horizontally tabular cells with outer walls greatly thickened and arched convexly outwards. Lateral walls are undulate. Stomata occur on both the surfaces and are accompanied by subsidiary cells one of which is smaller than the other two. The front cavity is placed in a depression formed by outer thickened walls of the epidermal cells. Guard cells are placed in the plane of the surrounding cells. (Fig. 5.) Stomata on the axis are numerous and have the same characters as those on the leaf. Mesophyll is isobilateral, and is characterised by a middle tissue which is composed of large thin-walled colourless polygonal cells, perhaps acting as water reservoirs in F. jacquemontii (Fig. 3) and of horizontally elongated green cells in F. macrantha (Fig. 7.) Internal secretary organs