Prototaxites is a genus of terrestrial fossil fungi dating from the Late Silurian until the Late Devonian periods, approximately 430 to 360 million years ago. Prototaxites formed large trunk-like structures up to 1 metre (3 ft) wide, reaching 8 metres (26 ft) in height, made up of interwoven tubes around 50 micrometres (0.0020 in) in diameter, making it by far the largest land-dwelling organism of its time.
