Alsophila alpina, synonym Cyathea alpicola, is a species of tree fern native to central Sumatra, where it grows in montane rain forest at an altitude of 2000–2750 m. The erect trunk can reach 5 m or more in height. Fronds are bi- or tripinnate and usually 2–3 m long. They have a tendency to persist on the plant after withering, forming an irregular skirt around the trunk. This species has a spiny stipe, which is covered with a woolly layer of scales. There appear to be two forms with different scales; either dark glossy brown with a broad paler margin and fragile edges, or small, brown and finely fringed. Sori are covered by thin, fragile indusia and occur near the midvein of fertile pinnules. The closest relative of A. alpicola is thought to be Alsophila polycarpa, which differs by lacking spines altogether. Alsophila macropoda and Alsophila magnifolia may also be closely allied with this species.
Alsophila aneitensis, synonym Cyathea aneitensis, is a species of tree fern native to Vanuatu and possibly New Caledonia. This species has an erect trunk up to 3 m tall. Fronds are bipinnate and may reach 2 m in length. The rachis and stipe are either very dark and smooth or have a few scales towards the base of the stipe. The scales are dark and narrow. Sori occur near the pinnule midvein and are covered by large, thin, fragile indusia. The closest relative of A. aneitensis appears to be Alsophila vieillardii. It can be distinguished from that species by its very dark stipes and frond bases.
Alsophila apiculata, synonym Cyathea apiculata, is a species of tree fern native to Sumatra, where it grows in montane rain forest at an altitude of about 1800 m. The trunk is erect and usually 5 m tall or more. Fronds are bi- or tripinnate and 2–3 m long. The stipe is pale, becoming darker towards the base. It is covered with dark scales with pale, fragile edges. Sori occur near the midvein of fertile pinnules and are covered by thin, very fragile indusia.
Alsophila apoensis, synonym Cyathea apoensis, is a species of tree fern native to Mindanao, Negros and southern Luzon in the Philippines, where it grows in dense forest at an altitude of approximately 1800 m. The trunk is erect and 2–5 m tall. The rachis is dark and warty. The stipe is covered with scattered scales, which are either large, dark and glossy, or small and dull brown. Sori are round and occur near the fertile pinnule midvein. They are covered by thin, brown, cup-like indusia.
Alsophila approximata, synonym Cyathea approximata, is a species of tree fern endemic to Madagascar. The trunk is erect, spiny and about 2 m tall. Fronds are bipinnate and usually 2 m long. They often form a crown of two whorls of about seven fronds each. Dark brown scales with a paler margin cover the stipe. Sori are round and occur near the fertile pinnule midvein. They are covered by thin, brown indusia, which are cup-like in appearance.
Alsophila biformis, synonym Cyathea biformis, is a species of tree fern native to New Guinea and the Maluku Islands, where it grows against trees in mossy forest and rain forest at an altitude of 850–2200 m. The climbing trunk is very thin, only 1–2 cm in diameter, but can reach 3 m in height. The apex of the trunk is covered in scales. Two types of fronds are produced, simple pinnate fronds, which are sterile, and bipinnate fronds, which may be fertile. The stipe is smooth, glossy and very dark, almost to the point of being black. It is covered at the base with long, very dark scales that have a pale margin. Fertile pinnules are distinctly stalked and lobed. Sori occur in four pairs per pinnule lobe and lack indusia.
Alsophila borneensis, synonym Cyathea borneensis, is a species of tree fern native to southern parts of Thailand and Cambodia, as well as the Malay Peninsula and Borneo, where it grows in lowland forest at an altitude of 400–1100 m. The trunk is erect and usually up to 2 m tall or more. Fronds are bi- to tripinnate and 2–3 m long. The stipe is spiny and warty. It is covered with scattered scales that are dark, glossy and have narrow, fragile edges. Sori are close to fertile pinnule midveins and covered by thin indusia.
Alsophila callosa, synonym Cyathea callosa, is a species of tree fern endemic to Luzon in the Philippines, where it grows in midmontane forest. The trunk is erect and about 3 m tall or more. Fronds are bi- or tripinnate and 1–2 m long. The stipe is spiny and covered with scattered scales that are dark and have pale, fragile edges. Sori occur near the midvein of fertile pinnules and are covered by thin, pale indusia.
Alsophila camerooniana, synonym Cyathea camerooniana, is a species of tree fern native to Sierra Leone, Cameroon, northern Angola and western Uganda, where it grows in montane forest at an altitude of 900–1200 m. The trunk is erect and 2–3 m tall. Fronds are pinnate and 2–3 m long. The rachis ranges in colour from dark to pale and has some hairs on the underside. The stipe is dark and is covered with scales throughout. Where scales have fallen, small warts are present. The scales are glossy brown and have a thin, dull edge. Sori occur at the forks of veins and are covered by thin indusia, which range in shape from cup- to saucer-like.
Alsophila catillifera, synonym Cyathea catillifera, is a species of tree fern native to eastern New Guinea, where it grows in montane scrub at an altitude of about 2800 m and above. It is a rare plant, known only from the type locality. The erect trunk is up to about 1 m tall and 10 cm in diameter. Characteristically of this species, the trunk often branches at the base. Fronds are bi- or tripinnate, 1–2 m long and may bear a pair of reduced pinnae towards the base. There are usually around six live fronds per crown at any one time. The stipe is spiny, warty and pale on the upper surface to dark at the base. It is |covered with scattered basal scales that are glossy dark brown and have a paler margin. Stipes are persistent with bases retained on the trunk. Sori occur near the midvein of fertile pinnules and are covered by thin, brown indusia that are saucer-like in appearance.
Alsophila hermannii, synonym Cyathea christii, is a species of tree fern endemic to Mindanao in the Philippines, where it grows in forest at an altitude of 900–1800 m. The trunk is erect and may be 5 m tall or more. Fronds are bi- or tripinnate and 2–3 m long. The stipe is covered with some warts and narrow, brown scales. Sori occur near the midvein of fertile pinnules and are covered by thin, fragile indusia.
Alsophila cucullifera, synonym Cyathea cucullifera, is a species of tree fern native to eastern New Guinea, where it grows in montane forest at an altitude of about 2400 m. The trunk is erect and 2–3 m tall. Fronds are bi- or tripinnate and 2–3 m long. Characteristically of this species, they occur in two whorls of four to six fronds each. The stipe is warty and covered with scales. The scales are dark, glossy, have a narrow paler margin and are large towards the base. Sori occur near the fertile pinnule midvein and are covered by thin, pale brown indusia that are scale-like in appearance.
Alsophila doctersii, synonym Cyathea doctersii, is a species of tree fern endemic to Sumatra, where it grows in forest at an altitude of approximately 150 m. The trunk is erect and 2–3 m tall. Fronds are bi- or tripinnate and 2–3 m long. The stipe is covered with scattered flat, brown scales and some hairs. Sori occur near the fertile pinnule midvein and are covered by thin, brown indusia that are scale-like in appearance.
Alsophila everta, synonym Cyathea everta, is a species of tree fern native to western New Guinea, where it grows in the edges of forest or in mossy forest at an altitude of 1400–2800 m. The trunk is erect and up to 5 m tall. Fronds are bi- or tripinnate and 1–1.5 m long. Numerous fronds are present at any one time and form a dense crown. The stipe has some spines towards the base and is covered in scales. The scales are pale or dark, glossy and have pale fringed edges. Sori occur near the fertile pinnule midvein. They are round and covered by thin, brown indusia that are cup-like in appearance.
Alsophila halconensis, synonym Cyathea halconensis, is a species of tree fern native to the islands of Luzon and Mindoro in the Philippines, where it grows in forest at an altitude of 1200–1700 m. The trunk of this plant is erect and 2–4 m tall. Fronds may be bi- or tripinnate and more than 1 m in length. Conical spines and scales cover the stipe. These scales are dark brown in colouration and have fragile edges. Sori occur near the fertile pinnule midvein. They are protected by thin, pale indusia.
Alsophila × marcescens, synonym Cyathea × marcescens, commonly known as the skirted tree fern, is a tree fern endemic to the Cape Otway ranges in Victoria and Tasmania, Australia. It is a natural hybrid, apparently Alsophila australis × Alsophila cunninghamii. Large and Braggins (2004) note that it has characteristics midway between these two species. The spores of A. × marcescens are usually malformed although sterile. The trunk of this plant is erect and up to 10 m tall. Fronds may be bi- or tripinnate and 3–4 m in length. Dead fronds often persist, forming a characteristic skirt around the trunk. The stipe is thick, black and warty. The rachis and trunk are covered in shiny, dark brown scales. Sori are borne near the fertile pinnule midvein and are protected by thin indusia that are saucer-like in appearance.
Alsophila inquinans, synonym Cyathea inquinans, is a species of tree fern native to southwestern Sulawesi and possibly the Maluku Islands, where it grows in montane forest at an altitude of 2000–2800 m. This plant has an erect trunk that is usually 2–4 m tall. Fronds may be bi- or tripinnate and 1 m or more in length. The stipe is covered in scales. These scales are either large, red-brown, thin, with narrow fragile edges, or small, with a red apical seta. Sori are borne near the fertile pinnule midvein. They are protected by thin, brown indusia.
Alsophila junghuhniana, synonym Cyathea junghuhniana, is a species of tree fern native to southern and central Sumatra and western Java, where it grows in forest at an altitude of 1000–2000 m. The trunk of this species is erect and may be 2 m tall or more. Fronds are tripinnate and up to about 3 m long. The stipes of this species are persistent and form a skirt around the trunk. They are brown, spiny, and covered with glossy, dark brown scales. Sori are borne near the midvein of fertile pinnules and are protected by thin indusia.
Alsophila lepidoclada is a species of tree fern native to central and eastern New Guinea, where it is locally common in rain forest and mossy forest at an altitude of 200–1000 m. The trunk of this species is erect and usually 2–3 m tall. Fronds are bipinnate, about 1.5 m in length, and form a sparse crown. The stipe bears blunt spines and scales towards the base. These scales are glossy, dark brown in colouration, and have a paler, thin margin. The round sori are borne in groups of four to five per fertile segment. They are covered by deep, firm indusia that are cup-like in appearance.
Alsophila semiamplectens, synonym Cyathea semiamplectens, is a species of tree fern in north-eastern New Guinea at 3300 to 3590 metres. Its trunk is 1 to 2 metres tall. The stipe is covered by thin scales. The scales are either having a dark middle band and fragile edges or are pale all over. Fronds are bi- or tripinnate and 1–2 m long.
