Gingko Gallery

Maiden hair tree stem, SEM

Maiden hair tree stem. Coloured scanning electron micrograph (SEM) of a section through a maidenhair tree (Ginkgo biloba) stem. At centre is the pith, which consists of soft, spongy parenchyma cells. Outside of this is the secondary xylem, which transports water and nutrients around the plant. The next ring consists of secondary phloem, which transports carbohydrates and hormones around the plant. Outside of this are the cortex, periderm and bark (brown)

© SUSUMU NISHINAGA/SCIENCE PHOTO LIBRARY

Ginkgo leaf stalk, light micrograph

Ginkgo leaf stalk. Light micrograph of a transverse section through the leaf stalk (petiole) of a ginkgo tree (Ginkgo biloba). The outer epidermis (black-brown) surrounds the cortex, which consists of parenchyma cells (blue) with inter-cellular spaces and resin canals (white spacess) characteristic of gymnosperms. The kidney-shaped vascular cylinder (centre) is surrounded by a single-layer endodermis, inside which are the tracheid cells (red) of the xylem and the sieve cells (blue and light orange) of the phloem. Magnification: x14 when printed 10 centimetres wide

© DR KEITH WHEELER/SCIENCE PHOTO LIBRARY