Oleander leaf. Light micrograph (LM) of a transverse section through the leaf (pinna) of an oleander plant (Nerium oleander). Oleander is a xerophyte - a plant that is adapted to survive in arid conditions. Sunken stomata (gaps, lower left and right) help reduce water loss. Present is a central vascular bundle made up of phloem sieve cells (green) and xylem tracheids (red). Dicot leaves are dorsoventral as the upper and lower surfaces of the leaves are distinguished. The vascular bundle is large in dicot leaf whereas in monocot leaf, both small and large parallel vascular bundles are present. Magnification: x20 when printed at 10 centimetres wide.