Lichen  (Calicium corynellum)

This species is commonly called a 'pin-head' lichen as the fruiting bodies (the structures that produce the lichen's spores) are shaped rather like black pins, or tiny wine cups. The part of the lichen forming the main body of the organism is called the 'thallus'. On C. corynellum this is a bright yellow-green and powdery in appearance.