Gymnosphaera schliebenii, synonyms Alsophila schliebenii and Cyathea fadenii, is a species of tree fern endemic to the Uluguru Mountains in Tanzania, where it grows on exposed ridges and on the upper edge of montane forest at an elevation of 1700âÂÂ2100 m. The trunk is erect, up to 4 m tall and 3âÂÂ5 cm in diameter. Fronds are bipinnate. Characteristically of this species, the most basal pair of pinnae are reduced, often to veins alone.