cilium (noun, pl. cilia) – long-acute, multicellular hair-like outgrowth with the appearance of an "eye lash", generally originating from the margin or upper surface (but close to the margin) of a thallus lobe or along the margin of apothecia; consisting of a compact strand of agglutinated hyphae; generally visible with the naked eye and similar in shape to simple rhizines (therefore sometimes called marginal rhizines), however, never located on the lower thallus surface and not functioning as attachment organs. Related terms: hair, fibril, rhizine. This is:part of upper thallus surface. Kind of:upper surface structure.