About Angiopteris evecta (G.Forst.) Hoffm.
Angiopteris evecta is a self-supporting, evergreen, perennial fern that produces very large bipinnate fronds. It has a massive, trunk-like rhizome that can reach up to 1 m (3 ft 3 in) in diameter. Older sections of the rhizome lie along the ground, while new growth may grow vertically up to 1.2 m (3 ft 11 in) high. Arching, glossy green fronds emerge from the tip of the rhizome; these fronds can grow up to 9 m (30 ft) long and 2.5 m (8 ft 2 in) wide, with the fleshy green petiole (leaf stem) making up 2 m (6 ft 7 in) of the total frond length. Angiopteris evecta is said to have the longest fern fronds in the world. Despite their large size, the fronds have no woody strengthening tissue to hold them erect, and are instead supported entirely by the hydraulic pressure of the plant's sap. On either side of the petiole where it connects to the rhizome are flat, rounded, leathery, ear-shaped stipules called "auricles", which can measure up to 15 cm (5.9 in) in diameter. The fronds are bipinnate, with around 9 to 12 pairs of pinnae that grow up to 150 cm (59 in) long and 45 cm (18 in) wide. Each pinna holds approximately 30 to 40 pairs of pinnules that measure around 13 by 2 cm (5.1 by 0.8 in). Both the main rachis and the secondary rachillae (midribs) are pulvinate, meaning they are swollen at the base. This pulvinus, which can reach up to 20 cm (7.9 in) in diameter, is responsible for raising and lowering the frond. Sporangia grow on the underside of the pinnules, very close to the margin, in clusters of 5 to 8 opposite pairs. The full overall size of this fern can reach up to 7 m (23 ft) high and 16 m (52 ft) wide. Angiopteris evecta is native to southeast Asia and Oceania, ranging from Sri Lanka and Bangladesh in the west to Melanesia, Micronesia and Polynesia in the east, and from Japan in the north to northern and eastern Australia in the south. It has been introduced to most of the rest of tropical Asia, as well as Madagascar and parts of tropical America. It has become naturalised in Hawaii, Jamaica, Costa Rica and Cuba. This species grows in rainforests on very rich soils, often of volcanic origin, and prefers a very warm, wet climate. It is typically an understorey plant in well-developed rainforest, particularly along creek banks in deep sheltered gullies with good drainage and a plentiful supply of fresh water, though it is occasionally found in more exposed locations. Its preferred annual mean temperature range is 19–27 °C (66–81 °F), and annual precipitation between 1,000 and 5,400 mm (39 and 213 in). It grows at elevations from sea level up to 1,500 m (4,900 ft). The starchy rhizomes of Angiopteris evecta are eaten after extensive processing to remove toxins. They are also used to perfume coconut oil, flavour rice, and produce an intoxicating drink. The 1889 book *The Useful Native Plants of Australia* records that Indigenous Australians ate the pith of this fern.
