Wood Fibres. The wood fibres are elongated, the walls are thick and the cells are strongly tapering.
In quassia, white sandalwood, red sandalwood, and guaiac wood are characteristic crystals.
In quassia the vessels are finely pitted, yellowish, and distinct; in white sandalwood the vessels are coarsely and sparingly pitted and white translucent; in red saunders the vessels are coarsely pitted, bright red and distinct.
When studying woods we must consider the width of the medullary rays, the structure and cell contents of the medullary ray cells; the structure, color, and cell contents of the wood parenchyma; also the wood fibres.
CHAPTER VI
LEAVES
Leaves collectively constitute the greatest manufacturing plant in the world. Most of the food, clothing, and medicine used by man is formed as a result of the work of the leaf. The cell contents, structure, and arrangement of the different cells of the leaf differ in a marked degree from the cell contents, structure, and arrangement of the cells in the other organs of the plant. This accounts for the presence of the large amount of chlorophyll in the leaf, the presence of stomata, and the peculiar arrangement of the cells.
It should be ascertained if the stomata are above, even with, or below the epidermis; the nature of the epidermal cells, and, when present, the nature of the hypodermal cells; the number of layers of palisade parenchyma and whether it is present on both surfaces of the leaf, and the nature of the outgrowths from the epidermal cells.
KLIP BUCHU
The cross-section of klip buchu (Plate 108) has the following structure:
Epidermis. The epidermal cells of klip buchu are modified to form papillæ, the walls are yellowish white, and the papillate portion of the cell is nearly solid.