Sphaeropteris medullaris, synonym Cyathea medullaris, commonly known as mamaku or black tree fern, is a large tree fern up to 20 m tall. It is distributed across the south-west Pacific from Fiji to Pitcairn Island. Its other Māori names include katātā, kōrau, or pītau.
Alsophila albidosquamata, synonyms Cyathea albidosquamata and Sphaeropteris albidosquamata, is a species of tree fern native to the Maluku Islands, New Guinea and the Bismarck Archipelago, where it grows in rain forest and montane forest at an altitude of 620–2,500 metres (2,000–8,200 ft). The trunk is erect and about 2 m tall. Fronds are bi- or tripinnate and 1–1.5 m in length. The lower surface of the rachis is covered in scales and the stipe has scattered scales throughout its length. These are glossy and pale, with dull, fragile edges. Sori occur near the fertile pinnule midvein and have flat indusia which resemble small saucers.
Alsophila andersonii, synonym Cyathea andersonii, is a species of tree fern native to India, Bhutan and southern China, where it grows in moist valleys and montane forest at an altitude of 300–1200 m. The trunk is erect and 6–10 m tall. Fronds are bi- or tripinnate and 2–3 m long. The entire plant is relatively dark in appearance; the rachis is flushed with dark purple and the stipe is dark, almost to the point of being black. Dark, lanceolate scales with pale fringes are sparsely scattered along the length of the stipe. Sori occur near the midvein of fertile pinnules and lack indusia.
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 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 brooksii, synonym Cyathea brooksii, is a species of tree fern native to Cuba, Hispaniola and Puerto Rico, where it grows on serpentine soils in shaded ravines, along streams, and on forested slopes at an altitude of 250–950 m. The trunk is prostrate and only about 6 cm in diameter. Fronds are pinnate or bipinnate and up to 2 m long. The base of the rachis is covered with blackish scales that have a paler margin. Sori occur in two rows, one along each side of the pinnule midvein.
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 coactilis, synonym Cyathea coactilis, is a rare species of tree fern known only from the southern highlands of Papua New Guinea, where it grows in alpine shrubland at an altitude of about 3000 m. The trunk is erect and 2–3 m tall. Fronds are bi- or tripinnate and usually 1–2 m long. Characteristically of this species, they occur in two whorls of about ten fronds each. The underside of the rachis is covered with small, pale scales. The stipe is covered with pale scales that have dark, narrow and fragile edges. Sori are round and are covered by thin indusia that are cup-like in appearance. They occur near the fertile pinnule midvein.
Cyathea corcovadensis is a species of tree fern native to Paraguay and Serra do Mar in southern Brazil, where it grows in primary and secondary forest, as well as scrub, at an altitude of 250–2100 m. The erect trunk is short, usually about 30–60 cm tall. Fronds are bipinnate and 2.5 m or more in length. The rachis ranges in colour from brown to purplish and is covered with warts and scattered brown scales. Sori occur either between the fertile pinnule midvein and the edge of the lamina or just beside the midvein. They lack indusia. C. corcovadensis is a variable species, especially in terms of pinnule shape and degree of dissection.
Cyathea croftii is a species of tree fern endemic to Manus Island in the Admiralty Islands, where it grows in damp forest on steep slopes at an altitude of about 500 m. It is relatively uncommon in the wild. The trunk is erect, up to 3 m tall and about 6 cm in diameter. Fronds bi- or tripinnate and 2–3 m long. The rachis and stipe are often light green, particularly when young. They are slender and covered with glossy brown scales towards the base. Sori are small and occur in rows, one along each side of the pinnule midvein. They are covered by thin indusia.
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 fenicis, synonym Cyathea fenicis, is a species of tree fern native to the Philippines, Taiwan, and Orchid Island, where it grows in wet forest, forest margins and on hillsides. The trunk is erect, up to 1 m tall and about 6 cm in diameter. Fronds are tripinnate and 1.5–2 m long. Characteristically of this species, the lowest pinnae are usually reduced. The stipe is spiny and ranges in colour from brown to purple-dark brown. It bears two types of scales: long dark brown scales as well as minute brown ones. Occasionally the scales are pale. Sori are round and arranged in two rows, one on either side of the pinnule midvein. They are covered by very small indusia that resemble scales in appearance.
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.
Alsophila grevilleana, synonym Cyathea grevilleana, is a species of tree fern endemic to Jamaica, where it grows in moist gullies and on wooded hills in both calcareous and noncalcareous soils at an altitude of 200–1200 m. The trunk of this plant is erect, about 7 m tall, and 10–15 cm in diameter. It is characteristically clothed in old stipe bases, brown scales and blackish spines. Fronds are tripinnate, dark green in colour, and up to 4 m in length. The last pinnae are sometimes separated, forming a distinctive clump around the trunk apex. The rachis is yellow-brown and almost smooth. This species has a long, dark brown stipe with a few scattered spines. Sori are produced in four to six pairs along the pinnule midvein. They are protected by pale brown indusia that are cup-like in appearance.
Alsophila acaulis, synonyms Alsophila denticulata and Cyathea hancockii, is a species of tree fern native to the Ryukyu Islands, Japan, Taiwan and Hong Kong. The specific epithet hancockii commemorates William Hancock (1847-1914), who collected numerous plants in Japan, China and Southeast Asia. It grows in forest, on stream banks, and in forest margins at an elevation of about 600 m or higher. As of August 2021, Plants of the World Online treated this species under the name Alsophila denticulata.
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.
Sphaeropteris elmeri, synonym Cyathea elmeri, is a species of tree fern native to the Philippines, Talaud Islands, and northern Sulawesi, where it grows in forest at an altitude of 500–1400 m. The trunk of this plant is erect and 5–10 m tall. Fronds may be bi- or tripinnate and up to 2 m or more in length. The lower surface of the rachis is distinctively pale and warty. The stipe is covered with scales and has warts towards the base. The scales are large, tapering, thin, and medium brown in colouration. Sori are borne near the fertile pinnule midvein. Indusia are absent.
Sphaeropteris propinqua, synonym Cyathea propinqua, is a species of tree fern native to Fiji and possibly Samoa, where it grows in wet forest. The trunk of this plant is erect and slender, growing to 10 m in height. Fronds may be bi- or tripinnate and 2–3 m long. Dull brown scales cover the dull, dark stipe of this species. The scales are minute along most of its length, becoming thick and fleshy towards the base. Sori are borne halfway between the pinnule midvein and the edge of the lobe. Indusia are present.
Alsophila imrayana, synonym Cyathea imrayana, is a species of tree fern native to Dominica, Costa Rica, Panama, Venezuela, and Ecuador.
