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.
Gymnosphaera annae, synonyms Alsophila annae and Cyathea annae, is a species of tree fern native Sulawesi and to Ambon in the Maluku Islands, where it grows in forest from sea level to about 650 m. The erect trunk is slender and may be as tall as 3 m. Fronds are bipinnate and 1–2 m in length. Characteristically of this species, the final pair of pinnae are usually reduced and occur towards the base of the stipe. The stipe is dark, slender and covered with scattered scales. These are dark, glossy and have a pale dull margin. Fertile pinnules are normally short-lobed. Sori lack indusia and occur two to four per pinnule lobe.
Gymnosphaera baileyana, synonyms Alsophila baileyana and Cyathea baileyana, also known as the wig tree fern, is a species of tree fern native to northeastern Queensland in Australia, where it grows in wet gullies and forest at an elevation of 850–1200 m. It is a rare species that is seldom found in the wild. The erect trunk is 4–5 m tall, approximately 10 cm in diameter and may be covered in stipe bases in the upper regions. C. baileyana is notable for being able to develop offshoots from the base of the trunk. Fronds are bi- or tripinnate and may be exceptionally long, up to 7 m, though they are usually around 2–3 m. The rachis and stipe are dark to darkish red, scaly and may be warty, but lack spines. Scales on the rachis and stipe are purplish brown to black and have a long hair-like apex. Characteristically of this species, the last pair of pinnae are separated from the others along the rachis and may form a clump around the trunk apex. Sori are circular and occur in one to three rows along the pinnule midvein. They lack indusia.
Gymnosphaera biformis, synonyms Alsophila biformis and 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 elevations 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 caudata, synonym Cyathea caudata, is a species of tree fern native to the islands of Luzon and Mindanao in the Philippines, where it grows in montane forest. The trunk is erect and up to 4 m tall or more. Fronds are bi- or tripinnate and 1–2 m long. The stipe is warty and covered with dark, narrow, glossy scales. Sori are borne near the midvein of fertile pinnules and are protected by firm, brown indusia. As of April 2022, Plants of the World Online treated it as a synonym of Alsophila speciosa.
Alsophila costularis, synonyms Cyathea chinensis and Sphaeropteris chinensis, is a species of tree fern native to Yunnan in China, Sikkim in India, as well as Nepal, Myanmar, Laos and Vietnam. Plants grow in forest and montane forest at an altitude of 900–1800 m. The trunk is erect and 1–2 m tall. Fronds are bipinnate and 1–2 m long. The stipe is either long and warty or has short spines towards the base as well as scattered glossy dark brown scales with fragile edges. Sori occur near the midvein of fertile pinnules and are covered by thin indusia.
Alsophila costalisora, synonym Cyathea costalisora, is a species of tree fern native to western New Guinea, where it grows on the edges of forest and in moist hollows at an altitude of 1900–3225 m. The trunk is erect, up to 4 m tall and may branch near the base. Fronds are bi- or tripinnate and 1–1.5 m long. The stipe is warty, especially where scales have fallen. The scales are pale and have a distinctive dark glossy central region, with a paler dull margin. Sori are round and occur near the fertile pinnule midvein. They are covered by firm, dark indusia that are cup-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 exilis, synonym Cyathea exilis, is a species of tree fern endemic to the Cape York Peninsula in Queensland, Australia, where it grows in vine forest on a substrate of sandstone. It is a rare plant known only from one location, specifically by a stream in Mann Creek in the William Thompson Range. In its natural habitat, A. exilis is reportedly accompanied by Pandanus and Calamus plants. The trunk is erect, up to 4 m tall and 4–8 cm in diameter. It produces several buds, often one at each stipe base. Fronds are bipinnate and up to 1 m long. The rachis and stipe range in colour from brown to dark brown or black-brown and are covered in blunt spines and scales. The scales are dull brown in colour and bear terminal setae, mostly one each. Sori are round and occur on either side of the pinnule midvein. Indusia are absent.
Alsophila geluensis, synonym Cyathea geluensis, is a species of tree fern native to central and eastern New Guinea as well as the Louisiade Archipelago, where it grows in mossy forest. In New Guinea itself, plants grow at an altitude of 1000–2000 m, however they are present at lower elevations of 700–900 m on associated islands. The trunk of this tree fern is erect and may be 5 m tall or more. Fronds are bi- or tripinnate and 1–2.5 m long. They are usually about ten live fronds present in the crown at once. The stipe may be warty and/or have short spines as well as many scattered scales towards the base. These scales are pale to dark and have dull, fragile edges. Sori occur near the fertile pinnule midvein and are protected by pale, thin indusia. A. geluensis is a variable taxon and further study is needed to determine whether it does not in fact represent a species complex.
Gymnosphaera glabra, synonyms Alsophila glabra and Cyathea glabra, is a species of tree fern native to Borneo, western Java, Sumatra, the Lesser Sunda Islands, Sulawesi, and the Malay Peninsula, where it grows in lowland swamp forest and montane forest at an elevation of up to 1500 m. The trunk of this plant is erect and 2–4 m tall. Fronds are bi- or tripinnate and 1–2 m in length. Characteristically of this species, the lowest pinnae may be significantly reduced. The stipe is very dark and bears basal scales. These scales are dark, glossy and have a paler margin and fragile edges. Sori are produced in groups of one to three on fertile pinnule veins. They lack indusia.
Alsophila gregaria, synonym Cyathea gregaria, is a species of tree fern endemic to eastern New Guinea, where it grows in lowland forest and coastal rain forest, often forming clumps, at an elevation of up to 100 m. The trunk of this plant is erect and usually 4–5 m tall and about 10 cm in diameter. Fronds may be bi- or tripinnate and 2–3 m in length. The stipe bears spines, but has few scales. These scales are medium brown in colouration and have a paler margin. Sori occur near the fertile pinnule midvein and lack indusia.
Alsophila heterochlamydea, synonym Cyathea heterochlamydea, is a little-known species of tree fern native to the islands of Luzon, Panay, Negros and Mindanao in the Philippines, where it grows in montane forest. The trunk of this plant is erect and usually up to 4 m tall or more. Fronds may be bi- or tripinnate and 1–2 m in length. The stipe is warty and/or bears short spines and scales. These scales are dark, glossy and have a narrow pale margin. Sori are borne near the fertile pinnule midvein and are protected by firm, brown 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 khasyana, synonym Cyathea khasyana, is a species of tree fern. Its natural distribution extends from India to Myanmar, although it is absent from Sri Lanka. A. khasyana grows in forest at an altitude of 1400–1700 m. The trunk of this plant is erect and 5–7 m tall. Fronds may be bi- or tripinnate and 2–3 m in length. A. khasyana has a long, dark stipe that is covered in numerous scales. These scales are dark and have broad, pale, fringed edges. Sori are borne near the midvein of fertile pinnules and lack indusia.
Alsophila imbricata, synonym Cyathea imbricata, is a species of tree fern endemic to Western New Guinea, where it grows in open forest at an altitude of 3240 m. The trunk of this plant is erect and approximately 2 m tall. Fronds may be bi- or tripinnate and are usually less than 1 m in length. The stipe is dark, spiny, and covered with caducous scales. These scales are glossy brown in colouration and have a paler margin and fragile edges. Sori are borne in groups of one to four per pinnule lobe. They are protected by firm indusia.
Alsophila incisoserrata, synonym Cyathea incisoserrata, is a species of tree fern native to the Malay Peninsula and the state of Sarawak on the island of Borneo, where it grows in forest and forest margins from the lowland to approximately 1250 m. The trunk is erect, about 4 m tall and 12 cm in diameter. Fronds may be bi- or tripinnate and 1–2 m in length. The stipe of this species is partly persistent and is sometimes retained on the upper trunk. It is warty, bears conical spines, and is sparsely covered with scales. These scales may be either small and fringed or bullate. Sori are borne near the fertile pinnule midvein. They are protected by very small, often bilobed indusia.
Alsophila javanica, synonym Cyathea javanica, is a species of tree fern native to western Java and Sumatra, in Indonesia. It grows in rain forest and on riverbanks at an altitude of 250–1500 m.
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 arfakensis, synonym Cyathea kanehirae, is a species of tree fern native to western New Guinea, where it grows in montane forest at an altitude of 1600–2700 m. The trunk of this plant is erect and 1–4 m tall. Fronds may be bi- or tripinnate and 1–2 m in length. The rachis is smooth, while the stipe is dark and warty. The stipe is covered with flat, brown, scattered scales. Sori are borne near the fertile pinnule midvein. They are protected by small indusia that are cup-like in appearance.
