The medullary ray cells exhibit their height and length. The walls of the cells are yellowish white and strongly porous.
Wood Parenchyma. The wood parenchyma cells have yellowish, thin walls and blunt end walls.
Wood Fibres. The wood fibres have thick, yellowish-white walls, and the end of the cells are strongly tapering.
TANGENTIAL SECTION QUASSIA
The tangential section of quassia (Plate 106) shows the following structure:
Vessels. The vessels are very long and broad and the yellow walls are marked with clearly defined pits.
Medullary Rays. The tangential section shows the cross-section of the medullary ray bundle and the cross-section of the medullary ray cell.
The medullary ray bundle varies in width from one to five cells. The ends of the bundles are always one cell in width, while the central part of the bundle is frequently five cells in width.
The medullary ray cell varies in size, structure, and shape according to the part of the cell cut across. The cells cut across the centre show hollow spaces, but the cells cut just above or below the end wall show a strongly pitted surface. The cells forming the end of the bundle are larger than the cells forming the centre of the bundle.
Wood Parenchyma. The wood parenchyma cells are greatly elongated and the walls are thin and yellowish white. The ends of the cells are blunt.