Native Plants of Hawai‘i - Dicranopteris linearis

Dicranopteris linearis

Gleicheniaceae or False staghorn fern family

Synonyms: Dicranopteris dichotoma, Dicranopteris dichotoma var. emarginata, Dicranopteris emarginata, Dicranopteris emarginata var. inaequalis, Dicranopteris hawaiensis, Dicranopteris linearis f. emarginata, Dicranopteris linearis f. linearis, Dicranopteris linearis var. maxima, Dicranopteris sandwicensis, Gleichenia dichotoma, Gleichenia dichotoma var. emarginata, Gleichenia dichotoma var. tomentosa, Gleichenia emarginata, Gleichenia hawaiensis, Gleichenia hermanii, Gleichenia linearis, Gleichenia linearis var. maxima, Mertensia dichotoma, Mertensia emarginata, Mertensia hawaiensis, Mertensia linearis, Polypodium dichotomum, Polypodium lineaaris, Polypodium lineare

Uluhe

Unuhe

False staghorn fern, Old world forked fern

Natural Range & Environment

Dicranopteris linearis is native to the Old World tropics and subtropics, including: Africa, Asia, Indonesia, Australia, New Zealand, and Polynesia (including Hawai‘i) [Palmer 2003]. In Hawai‘i, it is indigenous to all the main Islands except Ni‘ihau and Kaho‘olawe, where it is found in mesic to wet forests, often covering steep slopes from near sea level to 2,000 m (6,562 ft) [Flora of the Hawaiian Islands].

Uluhe is one of the most common, perhaps THE MOST common, native ferns in Hawai‘i. It can be seen growing both in the open under full sunlight as well as in the deep shade of a closed-canopy forest. New hikers are often cautioned to avoid wandering off the trail into an uluhe thicket because the fern can conceal dangerous cliff drop-offs.

Uluhe fronds have indeterminate growth allowing just a few plants to dominate large areas (photographs courtesy of John Game CC BY 2.0 and Forest & Kim Starr CC BY 3.0 US). It all starts with a tall fiddlehead (photograph courtesy of acezhou CC BY-NC 4.0) that forks and unfolds. The process then repeats one or more times **** (photograph courtesy of The Nature Conservancy in Washington (wavolunteer) CC BY-NC 4.0). Uluhe fronds can be hairless to extremely hairy (photograph courtesy of Forest & Kim Starr CC BY 3.0 US). Header photograph of sori courtesy of G.D. Carr ©.

Description

paraphrase Palmer's description of growth

compare to Diplopterygium pinnatum and Sticherus owhyhensis

Check out this really great Instagram video by hawaiian.plants and lualimahawaii showing the differences between the three species of uluhe!

Diplopterygium pinnatum (photograph courtesy of Forest & Kim Starr CC BY 3.0). Note that D. pinnatum forks only once while Dicranopteris linearis and Sticherus owhyhensis fork repeatedly.

You can often seen the larger frond Diplopterygium pinnatum growing side-by-side with the smaller frond Dicranopteris linearis.

Sticherus owhyhensis (photograph courtesy of ka_y_ak CC BY-NC 4.0). Note the pinnae on the rachis below the fork, whereas Dicranopteris linearis lacks pinnae in this region of the rachis.

Growth Requirements

General

If you are fortunate enough to have uluhe growing on your property or in a landscape (e.g., your mountain retreat), DO NOT dig it up or attempt to transplant it — BUT it's growing right where I want to put my hot tub! Perhaps because it's so common in the wild, many before you have tried to either transplant or vegetatively propagate (e.g., cuttings) uluhe. ALL have failed.

Romanchak et al. [2006] conducted an important horticultural study of uluhe. (Here is a link to a 2005 online presentation of their experiments. To summarize the results, they found that:

The answer for how to cultivate uluhe? (Photograph courtesy of Forest & Kim Starr CC BY 3.0 US.)

Pests and Diseases

add two-spot leafhopper photo

Leaf hopper damage **** (photograph courtesy of Forest & Kim Starr CC BY 3.0 US).

Uses

Ancient Hawaiian

According to Degener [1973], "Hawaiians in former times occasionally drank an infusion of the uluhe as a laxative." There is a somewhat similar statement made by Hubbard [1952] about page 6 (unnumbered): "An infusion was prepared from the ULUHE, which the Hawaiians drank as an emetic, according to Fowler" [1940]. Unfortunately, I (Koebele) have been unable to access Fowler [1940] directly to confirm Hubbard's statement. Additionally, an emetic is a substance used to induce vomiting, not bowel movement.

Modern

Special Features and Information

General

Blech

Hawaiian Name

Doodia

Etymology

Dicranopteris comes from the Greek words, dikranos, meaning "two-pronged," and pteris, meaning "fern," referring to the forking growth pattern of the plant's fronds [Palmer 2003]. The species name, linearis, is Latin, meaning "having the form of a line," [Wiktionary] possibly referring to the plant's linear growth behavior.

BPK