Heather leaf. Light micrograph (LM) of a transverse section through the leaf (pinna) of a heather plant. The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acid and infertile growing conditions. Heather is a xerophytic plant and the exposed areas of the leaf are protected from water loss by a layer of thick epidermal cells covered by a uniform layer of cuticle. The lower surface of the leaf has a covering of fine hairs designed to collect and retain wate. 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: x15 when printed at 10 cm. wide.