Morphological and anatomical characteristics of Cetraria aculeata (a, d, g, j) and Diploschistes muscorum (b, c, e, f, h, i, k, l): a, b lichen thallus; d, e, g, h thallus cross sections in light microscope; j, k thallus cross-section in SEM; c grain of quartz sand surrounded by fungal hyphae; f, i, l calcium oxalate crystals on thallus surface. Black arrows indicate melanin pigments, red arrows indicate calcium oxalate crystals and yellow asterisks indicate grains of quartz sand trapped inside the thallus.