Although it looks like it’s from another planet, this unique fern species actually grows on the Hawaiian Islands – but only there, and indeed in alien environments.

A group of aliens? Image credit: brewbooks

Amaumau fern (Sadleria cyatheoides) is a fern species that is endemic to Hawaii, which means it only grows there and nowhere else in the world. It is found in various habitats, such as lava flows, open areas, and wet forests, and can survive in harsh conditions.

The plant, also called ʻamaʻu, can endure high temperatures and direct exposure to sunlight, which give its leaves of a reddish hue. According to some sources, it can even withstand temperatures up to 100 degrees Celsius, so it can survive near even active lava flows. It can also cope with drought well and thrives in the arid Kau Desert region near Kilauea crater. It is often one of the first plants to grow on fresh lava flows, alongside the ohia tree.

Direct exposure to sunlight gives the fern’s leaves a reddish hue. Image credit: Forest & Kim Starr

The amaumau fern has a unique appearance. It looks like a miniature tree fern, with a short trunk and a crown of fronds. The fronds are usually green, but, as noted above, they can turn red when exposed to too much sun. This is a clever adaptation that protects them from harmful rays. The red color also makes the fern stand out among other plants, attracting pollinators and admirers alike.

A beautiful natural curve. Image credit: brewbooks

The amaumau fern has a rich cultural history in Hawaii. Its name comes from the Hawaiian word for “burning”, which refers to its ability to grow on volcanic soil. The plant was used by ancient Hawaiians for various purposes, such as medicine, food, and clothing. They extracted a red dye for KAPA cloth from the outer trunk of the amaumau. Moreover, the leaves of this fern were used as lining and thatching materials for homes, while the young leaves and inner stem pith were occasionally cooked and eaten.

The amaumau fern grows at the most impossible places and can withstand the harshest volcanic conditions. Image credit: Forest and Kim Starr

The amaumau fern is a common and widespread species in its native range, but it is rarely cultivated in private or public collections. It prefers moist to wet soils, full sun to partial shade, and can tolerate wind. It can be grown as an accent plant or in containers. The plant is not directly threatened by extinction, but it may face some threats from invasive plants and animals.

The birth of new ‘aliens’. Image credit: Kenneth Alcorn

Truly a remarkable species.

Sources: 1, 2, 3, 4, 5, 6