Chaenothecopsis vainioana (Nádv.) Tibell

Chaenothecopsis vainioana is a species of tiny, pin-like fungus that lives on lichens and algal colonies, belonging to the family Caliciaceae. The species is named in honour of the Finnish lichenologist Edvard August Vainio. These fungi produce distinctive black, stalked structures resembling miniature matchsticks that measure less than a millimetre in height, with oval-shaped heads containing spores. They typically grow on the surfaces of lichens containing specific types of green algae, particularly favouring old oak trees in partially open woodland areas across several European countries. Despite its widespread distribution across hemiboreal Europe, including Finland, Sweden, Denmark, Greece, Estonia, and parts of Russia, C. vainioana has historically been underreported due to its minute size and specialised habitat requirements, making it appear rarer than records indicate.