A leaf of the hybrid poplar, Populus x candicans Aurora. The picture shows the pattern of cells that produce the variegated appearance of the foliage. Networks of lines show the vascular tissues that conduct water from the roots to the leaf (xylem) and sugars from the leaf to the roots (phloem). A major vein runs from upper left to the bottom of the frame. Areas and islands of dark green comprise cells that have developed normal chlorophyll-containing plastids (chloroplasts). Areas of creamy white are made up of cells where chlorophyll has failed to develop. This is due to random genetic changes within the cells: each leaf has a different appearance. Paler green areas appear where white tissue overlays normal green tissue. Aurora poplar is an attractive columnar tree, but is unsuitable for small gardens due to its habit of spreading by suckers. The height of the frame is approx 3cm.