Natural Range & Environment  

    Sadleria pallida is endemic to all the main Hawaiian Islands except Ni‘ihau and Kaho‘olawe. 

Description

Sadleria cyatheoides is a medium-sized to large (up to 13 ft [4 m]) [Palmer 2003] upright or decumbent fern with a lifespan well in excess of five years. Erect cultivated (and wild?) ʻamaʻu frequently fall over to become decumbent. Its trunk is not made of bark and wood, but rather is a thick fibrous rhizome with a starchy pith. 

    Sadleria cyatheoides has erect (i.e., non-drooping) fronds (blade and stipe combined) anywhere from about two to ten feet (0.6 to 3 m), primarily dependent on the age of the plant. Young fronds are a bright red, turning green when mature. Frond stipes are straw-colored, grooved, and naked (i.e., without scales) except at their base. Fiddleheads and young blades are covered with tan to brown pulu (scales) but become naked as they mature. The leathery blades are 1-pinnate to 2-pinnate (at their base) with a glossy dark green upper surface and a pale to whitish lower surface when mature. Veins are nearly invisible except near the pinnae margins. Old dead fronds are retained and form a "skirt" around the base of the fern.

    Sadleria cyatheoides, like the other Sadleria species, has long linear sori positioned in the center of the pinnules. The indusia (outgrowths of the blade that covers the sori) open inward. Species of Sadleria are divided and identified by frond size and droopiness, visibility of veins, and the shape, color, and abundance of scales.

    Check out this great short tiktok video by laulimahawaii about ʻamaʻu.

Identifying which species of Hawaiian Sadleria you are looking at can be a challenge. Most common is confusion between the three most common species: S. cyatheoides, S. pallida, and S. souleyetiana; the other three species are either less common (S. squarrosa, usually restricted to dark areas often near streams) or restricted to Kaua`i (S. unisori and S. wagneriana) [Palmer 2003]. Use this simple key along with the photographs below. Look first for the veins on the underside of the frond’s ultimate (smallest) segments. If they are easily visible (particularly when backlighted) then you have either S. pallida or S. souleyetiana; if they are hard or impossible to see then you have S. cyatheoides. To distinguish S. pallida from S. souleyetiana, count the number of ultimate segments pairs on each pinna. If it is less than 40 (usually less than 30) then you are looking at S. pallida; more than 40, you have S. souleyetiana. Also examine where the pinnae connect to the rachis because S. souleyetiana often (but not always) has an odd-looking basal segment overlapping the rachis, while S. pallida rarely has this overlapping segment.

Uses

Ancient and Post-contact Hawaiian

    Degener [1973] has, perhaps, the most comprehensive description of the many uses Hawaiians had for Sadleria. Below is my (Koebele) summary of his description along with a few additions or clarifications from other sources.

    In his description, Degener refers to Sadleria pallida by its synonym S. hillebrandii, which he says Hawaiians called ʻamaʻu. He also states that Hawaiians referred to S. cyatheoides as ʻamaʻumaʻu. 

    "A generation or two ago," referring to the 1800s, the hair-like scales near the developing fiddleheads of S. cyantheoides, called pulu ʻamaʻu, were harvested, similar to the pulu of Cibotium species, and shipped to California to be used as stuffing for pillows and mattresses. (See Uses;Modern on the Cibotium chamissoi page for a more complete description of the post-contact uses of pulu.) 

    Hawaiians beat Sadleria frond stalks together with other fiber plants (e.g., wauke, māmaki) to assist in "sizing" when making kapa; "sizing" involved measuring the kapa and creating lines along the edges to permanently record its size. The sap from rolled up fronds, called pepeʻe a palaholo, was used to either moisten kapa or create an adhesive to bind together or repair pieces of kapa [Krauss 1993]. The outer part of the trunk (and the young fronds [Krauss 1993]) were mashed to extract a juice that was then heated to evaporate and concentrate a red pigment used to dye kapa.

    Hawaiians would build temporary shelters using Sadleria cyantheoides, which is believed to be the origin of one name for the fire pit within Kīlauea Crater, Halemaʻumaʻu, meaning "the house of the ʻamaʻu."

    The starchy pith of Sadleria pallida was cooked in an imu, though not as commonly as hāpu‘u (Cibotium spp.). The young fronds were also eaten. 

    Hawaiians would cover the ground in drier places with Sadleria pallida and S. cyantheoides fronds. They would then remove the fronds whenever it rained, plant their seeds or cuttings, and re-cover the ground to reduce evaporation.

    Both Sadleria cyantheoides and S. pallida fronds were sometimes used for thatching hale whenever pili (Heteropogon contortus) was scarce. The fronds were also used to cover and rainproof the ridge and corners of hale made from pili or other materials. Lastly, Sadleria pallida fronds were placed to cover the ground on the side of a heiau where an ali‘i and his attendants would walk.

    Kaʻaiakamanu [1922; 2003] claims ʻamaʻu or ʻāmaʻumaʻu, prepared with other plant parts, was used to "cure asthma and kindred troubles," bring to a head boils, blind pimples, and similar afflictions, and treat palahū (rot) and kaokao ‘ino (syphilis). Krauss [2001] also claims ʻamaʻu was used to treat asthma; however, her prescription differs from that of Kaʻaiakamanu.  

Unless otherwise specified, the following uses by early Hawaiians were for ʻAmaʻu (Sadleria spp.) in general:

Agriculture:

The leaves, or fronds, were also used as mulch in gardens and dry-land kalo (taro) in drier parts of the islands. [5,8,11] In drier regions, fronds were laid over prepared ground. When the rains came, the fronds were removed, and seeds planted. After the rain, fronds were replaced as mulch to cut down evaporation. [11]

After harvesting the leaves, the wound of the fern was covered so that the plant would not die. [9]

Pukui mentioned of ʻamaʻu: "Hui ka lau o ka ʻamaʻu i uka ka wai o kahawai." (When the leaves of ʻamaʻu turn toward the upland, it is a sign of flood). When the wind blows the leaves of the ʻamaʻu fern so that they bend toward the mountains, it is also blowing clouds inland, which will produce rain. [13]

Clothing:

A red dye was extracted from the young fronds as well as the cortex of trunks of larger plants for kapa (tapa). [2,10] Leafstalks were beaten and used as sizing with bark in kapa making. [8] The sticky, pulpy sap from the open or rolled-up fronds* sometimes used in the kapa making process to keep the pulp moist and together or to act as a type of glue to weld strips kapa together or to repair kapa. [2,10]

Older stems were used for sizing kapa (tapa). [11]

Construction:

The fronds of ʻamaʻu were used as a temporary shelter in the forest, or as thatch for trim on corners or ridges, tied lenghthwise, as a waterproofing in these areas. Fronds, along with lau hala (Pandanus tectorius) or by themselves, were used for the entire roof thatching or even the walls, if pili (Heteropogon contortus) was scarce. [5,8,11]

Food:

ʻAmaʻu was an important famine food for the early Hawaiians or fed to pigs. [1,6,7] The starchy pith was occasionally cooked in an ʻimu, and the young shoots eaten raw or cooked. [2,5] Plants were powdered to make a beverage similar to tea or coffee. [12]

Household Furnishings:

The pulu (fuzzy hairs around emerging fronds or leaves) of ʻamaʻu, called pulu ʻamaʻu, resembles hāpuʻu (Cibotium spp.) and was also used as stuffing for pillows and mattresses. [5,11]

Medicinal:

The plants with other ingredients were pounded to make a juice applied to boils and pimples. The shoots were used for lung troubles, and inner bark pounded for asthma. [3,9] Leaves used for gout. [9] The dried leaves were used to treat the illness palahū (rot) and kaoko ʻino (syphilis). [4]

Religion:

To polytheistic Hawaiians, ʻamaʻu is one of the forms hat the pig demigod Kamapuaʻa assumes at will.

Royalty:

The ground over which aliʻi and attendants were to pass, or remain on at a dedication of heiau, was covered with ʻamaʻu fronds. [11]

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* Pepeʻe a palaholo (a rolled-up frond of ʻamaʻu) describes the ʻamaʻu ferns that furnish sap used in kapa making. It implies the same thought as the saying, "Great oaks from little acorns grow."

Modern