Native Plants of Hawai‘i - Doryopteris decipiens

Doryopteris decipiens

Pteridaceae or Maidenhair Fern family

Synonyms: Doryopteris decora var. decipiens, Doryopteris pedata, Litobrochia decipiens, Pteris decipiens, Pteris pedata

ʻIwaʻiwa

Kumuniu, Manawahua

Triangleleaf lipfern

Natural Range & Environment

Doryopteris decipiens is a rather common endemic fern found in dry shrublands, grasslands, and forests, often growing on exposed basalt 30-915 m (c. 98-c. 3000 ft) on all main islands and including Lehua [Palmer 2003].

ʻIwaʻiwa growing in a forest habitat at the base of the last wild nāʻū [Gardenia brighamii] on Oʻahu. This fern will die back, partially or fully, as a natural response to seasonal drought or dry conditions. (Photographs courtesy of Forest & Kim Starr CC BY 4.0; Forest & Kim Starr CC BY 4.0) ʻIwaʻiwa do well in pots, as these are in 8-inch cement pots, or in the ground with plenty of sun and good soil drainage as seen here with ʻilima (Sida fallax) or among mossy lava rocks in an urban landscape.

Description

Doryopteris decipiens is a small fern, up to a foot tall, with leathery, triangular, deep green fronds that are once-pinnate (divided once). It forms a crown, producing layers of persistent dead fronds that decompose slowly, creating a soil-like substrate for itself and other plants, helping to prevent invasive species. The stipes (petioles) are purplish-black to black, often longer than the blade itself [Palmer 2003].

Growth Requirements

General

ʻIwaʻiwa does well in containers or in the landscape with open air conditions in full to part-full sunny locations. I (Eickhoff) prefer to use cement or terra cotta pots for sufficient aeration at the root level so as not to retain too much moisture, but it does well in plastic containers too. I find that an equal mix media of peat, perlite and small grade (less than 1/2 inch) black cinder works great. You can top it with larger grade (greater than 1/2 inch) black cinder for a finished look.

While ʻiwaʻiwa is not difficult to grow, it may present a challenge for some growers especially if you love to water. Do not overwater this fern, nor does it like "wet feet" (constant water at the roots). Overwatering is probably the biggest failure in growing this beautiful fern, as I can personally attest to. It is un-fernlike in its growing conditions and prefers good drainage, good air movement, and sunny conditions to do well. If you have to second guess and think 'should I water my ʻiwaʻiwa?', then don't. Wait the next day or two. It won't die from underwatering, but it WILL most certainly die from overwatering it! So water it as you would other sun-loving and drier growing native plants with a well drained potting media to ensure perfect drainage and you should have good success with this fern.

A word about fertilizers. I (Eickhoff) give ʻiwaʻiwa kelp fertilizer on a regular monthly basis at a half the recommended dilution rate. Be sure to apply it over the fronds when fertilizing your plant.

ʻIwaʻiwa is a drought tolerant fern. During periods of low rainfall or high heat, mature fronds will die back to the ground as a survival mechanism, typically as a natural response to seasonal drought or dry conditions. So if it has been neglected in watering and appears to be dead, do not be quick to throw it out! Seriously! Though it may appear dead, it will likely regrow when moisture returns. In my experience, similar to the growing requirements for ʻihiʻihilauākea (Marsilea villosa), it is not necessary for ʻiwaʻiwa to go through a wet/dry cycle under cultivation to thrive. However, let it slightly dry between waterings (that's the key) and it will maintain its lush green fronds. It is also heat and wind tolerant.

Pests and Diseases

Doryopteris decipiens may occasionally get mealybugs or scale. Refer to the Pests & Diseases page for ways to eliminate these pests.

Uses

Ancient Hawaiian

No known uses by ancient Hawaiians.

Modern

Special Features and Information

General

Doryopteris, a genus of about 30 species [Palmer 2003], belongs to the Pteridaceae, the Maidenhair Fern family (order Polypodiales), containing about 50 genera and approximately 950 species [Britannica;Pteridaceae]. There are four species of Doryopteris endemic to the Hawaiian Islands: D. angelica (Kokeʻe area of Kauaʻi), D. decipiens, D. decora (main islands, except Niʻihau), and D. takeuchii (Diamond Head, Oʻahu). Additionally, a hybrid is known between D. decipiens × D. decora, which is uncommon on several of the main islands [Palmer 2003].

Hawaiian Name

Besides Doryopteris decipiens, the name ʻIwaʻiwa, often with added meanings, is given to other native Hawaiian ferns as well. These include Adiantum capillus-veneris (ʻiwaʻiwa; ʻiwaʻiwa hāwai, "purified by water;" ʻiwaʻiwa kahakaha,"striped iwaʻiwa"), Asplenium adiantum-nigrum (ʻiwaʻiwa), Asplenium aethiopicum (ʻiwaʻiwa a Kāne, "Kāne's ʻiwaʻiwa"), Asplenium macraei (ʻiwaʻiwa lau liʻi, "small-leaved ʻiwaʻiwa"), and Tectaria gaudichaudii (ʻiwaʻiwa lau nui, "large-leaved ʻiwaʻiwa") [Palmer 2003, Hawaiian Dictionaries].

Etymology

The generic name Doryopteris is from the Greek dory meaning spear, lance or pole, and -pteris -fern, -wing-like, -winged [Gledhill 2008, Palmer 2003], referring to the frond shape in some species. The Latin epithet decipiens means deceiving [Palmer 2003], misleading, or "not obvious," though its exact meaning in this context is unclear.

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