Alsophila rosenstockii, synonym Cyathea ascendens, is a species of tree fern native to northeastern New Guinea, where it grows in rain forest at an altitude of 800m–1000mm (2,600feet–3,000feetm). The erect trunk is slim and 1m–2mm (03feet–07feetm) tall. Fronds are bi- or tripinnate and may be over 1m (03feet) in length. They form a distinctive open crown. The stipe is covered in glossy scales with pale, fragile edges. Sori occur near the midvein of fertile pinnules and lack indusia.