Fig. 9.

Fibre cable of T. × glauca observed with a polarized light microscope equipped with crossed polars and a full-wave plate compensator. The chemically untreated fibre cable was placed in water and squashed between the cover glass and the slide to push the crystal cells aside and make the fibre cells visible. The long axis of each fibre cell was oriented parallel to the slow axis of the compensator. The fibre cells appear blue because the cellulose microfibrils are parallel to the long axis of each of the individual fibre cells that make up a cable.