Fluorescence micrograph of a transverse section through a moss (Polytrichastrum formosum) leaf. In general, moss leaves are one layer of cells thick, but there are some exceptions. In members of family Polytrichaceae the leaves are built of a single layer lamina, a midrib and a few to a dozen rows of lamellae on the dorsal surface in midrib part. Lamellae significantly enlarge the surface area of a leaf. Observed in ultraviolet (UV) light. Magnification: x166 when printed at 10 x 10 cm.