ALFRED PASIEKA / SCIENCE PHOTO LIBRARY ALFRED PASIEKA / SCIENCE PHOTO LIBRARY
Oak stem. Polarised light micrograph of a cross- section through the stem of an oak tree, Quercus sp. At upper frame (dark blue) is cork tissue of the bark, with bands of phloem cells (pink). At centre are concentric layers of tracheid (xylem) cells forming the wood of the oak stem. Metaxylem vessels appear as large ovals (purple). The concentric layers in this wood correspond to annual growth rings (a count of which would indicate the age of this stem). At lower left is the pith. Quercus robur, the English oak, may live to an age of 500 years or more, and would develop the same number of growth rings in the main tree trunk. Magnification: x18 at 6x7cm size.
Model release not required. Property release not required.