Pine needle. Darkfield illuminated polarised light micrograph of a cross-section through a pine needle, (Pinus sp.). The section shows a vascular bundle (upper centre) and transfusion tissue (blue) within the endodermis layer (orange) in the centre of the needle. Transfusion tissue is composed of parenchyma cells which fill the space between the vascular bundles. The vascular bundles contain conducting tissue; phloem which transports products of photosynthesis and xylem which transports water. Magnification: x200, when printed at 10 centimetres wide.