Pine root Light micrograph of a section through the root of a pine Pinus sp tree From outer to inwards outer layer of peridium dark red cortex made up of parenchyma cells red ring of secondary phloem blue cambium blue secondary xylem made up of tracheid cells pink scattered resin canals blue circular and meullary rays dark radial lines The centre of the root is filled with small primary xylem cells metaxylem brown Magnification x when printed centimetres wide
