Alsophila montana, synonym Cyathea costulisora, is a species of tree fern native to Sumatra. The trunk is erect and usually 1âÂÂ4 m tall. Fronds are bi- or tripinnate and 1âÂÂ2 m long. The stipe is covered with warts and scales. The scales are either pale and glossy or dark and flat. Sori occur near the fertile pinnule midvein and are covered by large, firm, brown indusia.