Clubmoss stem. Light micrograph (LM). Transverse section through the stem of the clubmoss Lycopodium clavatum. Clubmoss (Lycopodiella) is not a true moss but a primitive non-flowering plant which is more closely related to ferns. The layers from outer to inner are: the single-layered epidermis; the cortex; and the central vascular cylinder (stele). The cortex contains parenchyma cells (white) and sclerenchyma cells (red). The stele consists of xylem cells (tracheids, red), parenchyma cells and phloem. Magnification: x45 when printed at 10 centimetres wide.