‘Ama’uma’u fern (Sadleria cyatheoides)

Five Amaumau fern grow on lava flows created in the early 20th century with other pioneer species like ‘Ohi’a lehua.

Driving through the big island of Hawaii on the saddle road, the scenery changes drastically from vegetation introduced by ranches to hard lava rocks with little to no soil. Growing on it are some of the most versatile and hardy species of plants. These pioneer species are the first to inhabit rocky lava beds after the erupted magma cools down. Among those species is the Amaumau fern. The first time I saw this fern, I assumed it belonged to the more common fern order of tree ferns. I was pleasantly surprised to learn more about this fantastic fern. For now, it has taken the spot of my favorite species of ferns!

Amaumau fern belongs to the endemic genus Sadleria. It is found in all major islands of Hawaii and grows on lava flows, open spaces, and wet forests. The fern can tolerate extreme heat and direct sunlight, which gives its leaves a red tinge. The plant can grow vertically, like a small tree fern, or horizontally with its rhizomes covered with silver-colored dead leaves. 

The crater Halemaʻumaʻu, home to the goddess of fire and volcanoes, Pele, derives its name from this fern. Halemaʻumaʻu means “house of the ʻāmaʻu fern.”