Amphycribral Vascular Bundle of a Fern Rhizome - Pterídium aquilínum Big cells with red cell wall are tracheids. They serve in the transport of water. Around the xylem there are xylem parenchyma and phloem cells. A single row layer of small cells (with red content) that located circumferentially is endoderm. In the parenchyma there are amyloplasts which store starch granules. The authorial prepared mount, polychrome painted tissues Light microscopy, bright-field in transmitted light