Prototaxites
Prototaxites is an extinct genus of large macroscopic eukaryote dating from the Late Silurian until the Late Devonian periods. Prototaxites formed large trunk-like structures up to 1 metre (3 ft) wide, reaching 8 metres (26 ft) in height, made up of tiny interwoven tubules around 50 micrometres (0.0020 in) in diameter, making it by far the largest land-dwelling organism of its time.