Native Plants of Hawai‘i - Microlepia setosa

Microlepia setosa var. setosa

& setosa var. mauiensis

(formerly Microlepia strigosa)

Dennstaedtiaceae or Bracken family

Synonyms for Microlepis setosa var. setosa: Davallia hirta, Davallia setosa, Davallia strigosa, Dicksonia kaulfussiana, Dicksonia strigosa, Microlepia hirta, Microlepia setosa, Microlepia strigosa var. strigosa, Microlepia strigosa var. strigosa (Misapplied), Stenoloma tenuifolium, Trichomanes strigosum

Synonyms for Microlepis setosa var. mauiensis: Hypolepis strigosa var. mauiensis (Misapplied), Microlepia mauiensis, Microlepia strigosa var. mauiensis

Palapalai

Palai

Hay-scented fern, Lace fern, Rigid lace fern, Hairy palapalai (var. mauiensis)

Natural Range & Environment

Microlepia setosa var. setosa is an indigenous fern found on Kauaʻi, Oʻahu, Lānaʻi, Molokaʻi, Maui, and Hawaiʻi Island, mostly in dry to moderately wet habitats, near sea level to over 5,800 ft. (1,770 m.) [Flora of the Hawaiian Islands, Palmer 2003]. Microlepia setosa is also native to the Himalayas, Sri Lanka, from southeast Asia to Japan, and Polynesia [Palmer 2003].

Microlepia setosa var. mauiensis is a rare and endemic fern, found on Oʻahu (Makaleha in the Waiʻanae Mts), Maui and Hawaiʻi Island [Flora of the Hawaiian Islands, Palmer 2003].

Kim Starr in a patch of palapalai in its natural habitat on Maui (Courtesy of Forest & Kim Starr) and in cultivation at a college campus on Oʻahu. Close-up of the underside of a frond showing the sori, a key to identifying ferns. It can be used in a non-native setting, such as at this mall on Maui with native or non-native plants (Courtesy of Forest & Kim Starr).

Description

Medium-sized ferns with fronds usually less than 40 inches (100 cm). Leaf color is light or pale to medium green. Stipe (stalk of a frond) is straw-colored and varies from sparse (var. setosa) to very hairy (var. mauiensis). Frond blades are 2- to 3-pinnate (leaf-divisions).

Growth Requirements

General

Palapalai is a low-maintenance fern that thrives in partially sunny locations with ample moisture. It flourishes under the canopy of large trees or shrubs, serving as a lush groundcover that conceals fallen leaves within its dense foliage. I (Eickhoff) have found that the growing conditions in cultivation for Microlepia setosa are the same for both varieties (i.e., mauiensis, setosa). So the following information will apply to both varieties, unless otherwise distinguished.

Palapalai can also thrive indoors, making it a versatile plant that can even be placed in bathrooms [Crowl 2007]. When grown in containers, it is important to repot the plant periodically as it tends to grow quickly [Nagata 1992]. A balanced fertilizer with micro-nutrients, such as 13-13-13, is essential for container plants. Kay Lynch, Lāʻau Hawaiʻi, suggests avoiding tilling solid fertilizers into the soil, as palapalai has a shallow root system and can damage roots.

It is worth noting that Microlepia setosa, a similar fern often sold under the name "Palapalai," may be found in garden stores. To ensure you are purchasing the native palapalai, inquire about its source [Nagata 1992].

Regular maintenance includes removing dead fronds for a clean appearance or leaving it as is for a natural look in the garden. While palapalai can tolerate somewhat dry or moist conditions, it thrives in well-drained, moist soil and does not fare well in hot, exposed areas [Nagata 1992]. The plant can withstand full sun but prefers some shade, especially in cooler mountainous locations [Nagata 1992].

Although palapalai may have some tolerance to salt spray, it is advisable to confirm this [Ka‘aiakamanu 2003].

Additionally, the plant is sensitive to herbicides, so caution must be exercised to prevent herbicide drift onto nearby plants, especially on windy days [Nagata 1992].

Pests and Diseases

Refer to the Pests & Diseases page for treatments.

Uses

Ancient Hawaiian

Palapalai have played a significant role in Hawaiian culture throughout history. Early Hawaiians utilized the fronds to adorn hula altars dedicated to Laka, the goddess of hula [Nagata 1992]. These versatile ferns were also commonly used to create head lei (lei poʻo), neck lei (lei ʻāʻī), and wrist lei (lei kūpeʻe), providing a soft and delicate touch against the skin of the wearer [Abbott 1992]. Regarding the medicinal properties, D.M. Kaʻaiakamanu believed palapalai to have psychological benefits, particularly in aiding those suffering from insanity [Ka‘aiakamanu & Akina 1922]. Furthermore, palapalai have been immortalized in Hawaiian songs (mele) and chants [McDonald & Weissich 2003].

Modern

Palapalai remains a crucial element in lei-making today, just as it was for early Hawaiians. Its delicate fronds are intricately woven into a lei that adorns the heads, wrists, and ankles of hula dancers. Each spring, leading up to the Merrie Monarch Dance Festival in Hilo, Hawaiʻi Island, there is a well known local tradition of hula hālau coming together to gather palapalai for both hula kahiko (ancient hula) and hula ʻauana (modern hula) performances.

While harvesting the fronds does not harm the fern populations, repeated trampling through the areas can disrupt other native groundcovers in the forests. Thus, palapalai is cultivated in many gardens throughout the islands, where it serves as a lush groundcover and is also utilized for its traditional purposes. We encourage you to try your hand at growing this easy fern yourself. Since palapalai is an indigenous fern, please buy from reputable local growers rather than from large retail store nurseries. See Where can you buy these plants? Please kōkua to keep our local palapalai populations native.

Special Features and Information

General

Palapalai is among a diverse group of approximately seventy Microlepia species in the Bracken or Hay-scented fern family (Dennstaedtiaceae) [Palmer 2003]. The most well-known member of this family is the bracken fern (Pteridium aquilinum), known as kīlau, indigenous to the Hawaiian Islands, and is considered one of the most common ferns in the world.

There are two native varieties of Microlepia setosa, the indigenous variety (var. setosa), and an endemic variety (var. mauiensis), as well as a natural hybrid that can be found in the main Hawaiian Islands. As previously mentioned, the endemic variety Microlepia setosa var. mauiensis is rare and can be found in mesic to wet forests in the Waiʻanae Mountains of Oʻahu, West and East Maui, and Hawaiʻi Island. Botanist Joel Lau has "seen it in three locations: West Makaleha, Mākaha, and Palikea" on Oʻahu

A less common relative, Microlepia speluncae, also known as Limpleaf fern, closely resembles Microlepia setosa but typically has larger and longer fronds. A quick way to differentiate between the two species is by picking the fronds - the fronds of M. speluncae will go limp after being picked, while M. setosa fronds will not [Palmer 2003]. Additionally, M. setosa has small bristle-like hairs on its leaves, while M. speluncae does not, being glabrous (no hairs).

There is a natural hybrid between Microlepia speluncae and M. setosa, known as Microlepia x adulteriana and has been found on Kauaʻi, Oʻahu, and Hawaiʻi Island. This hybrid forms large colonies where the two species coexist, and its name suggests an "adulterous" relationship between the two parental species [Palmer 2003].

Hawaiian Name

Palapalai refers to a common name for fern and can also refer to the Niʻihau name for the native fern Nephrolepis exaltata.

Etymology

The generic name Microlepia is derived from the Greek mikros, small, and lepis, scale, alluding to the small cuplike indusia (spore covering) of this genus [Palmer 2003]. The specific epithet setosa is from the Latin setosus, covered with bristles or stiff hairs [Gledhill 2008]. The former specific epithet strigosa is from the Latin strigosus, bristles or stiff hairs, in reference to the tiny, rigid hairs on the fronds of this species [Palmer 2003].

DWE