Native Plants of Hawai‘i - Machaerina mariscoides subsp. meyenii

Machaerina mariscoides subsp. meyenii

Cyperaceae or Sedge family

Synonyms: Baumea meyenii, Cladium meyenii, Machaerina meyenii

ʻAhaniu

ʻUki

Meyen's twigrush

Natural Range & Environment

Machaerina mariscoides subsp. meyenii is endemic to all the main Hawaiian Islands except Niʻihau and Kahoʻolawe, and is found in mesic to wet forest from 150 to 1220 m. (ca. 492 to 4003 ft.) [Wagner et al. 1990]. To add to Wagner et al. [1990] habitat description, we have most often seen ʻahaniu on exposed, windswept, wet or mesic summit ridges, and open areas along forest margins in full sun conditions.

ʻAhaniu is often seen on exposed, windswept, wet or mesic summit ridges, and open areas along forest margins in full sun conditions. Flowers are displayed here. (Photograph with ocean background courtesy of Kenneth R. Wood (NTBG) CC BY-NC 4.0.).

While commonly seen in the wild, ʻahaniu is rarely cultivated despite the fact that it does quite well with other sun-loving native species (i.e., Scaevola gaudichaudii, Panicum torridum) in landscapes, as pictured above and in the header. It is interesting to note that the Panicum torridum in the photo came up as volunteers (not intentionally sown) from a previous planting in this location when it was a hot and sunny area. Since some Panicum species are annuals (e.g., P. konaense, P. torridum) or can perform like it even though they may be perennials (e.g., P. niihauense), from personal experience, it is good to either allow them to re-seed on the spot or collect seeds for a future planting.

Description

ʻAhaniu is a large, non-woody, clumping perennial sedge that forms dense tufts, growing up to 3 feet (1 m) in height. The leaves are long, narrow, and strap-like, and have a beautiful, soft blue-green color. Further, unlike typical sedges, they lack a central midrib and have a distinct, slightly blue-green color hue. The flowers bloom year-round, producing long-lasting panicle inflorescences (up to 1.5 feet long) with small, dark brown spikelets. Each pollinated flower develops into a small, amber-brown, glossy achene that is broadly ovoid to subglobose.

The endemic subspecies meyenii differs from subsp. mariscoides by having a reduced structure of spikelets. The spikelets of subsp. meyenii have 3 to 4 glumes (dry, leaf-like bracts or scales) and are 1-flowered, with broadly ovoid to subglobose achenes 2 to 2.3 mm long. Subspecies mariscoides has spikelets with 5 to 6 glumes and up to 3 flowers, with ellipsoid to ovoid achenes 3.5 to 4 mm long [Wagner et al. 1990].

Growth Requirements

General

ʻAhaniu has the potential to be an awesome low elevation landscape sedge if it were more readily available. When it becomes available, it could easily replace the overused African iris (Dietes bicolor) or Silver Streak flax lily (Dianella tasmanica) in Hawaiʻi's residential or commercial landscapes.

ʻAhaniu is a beautiful and easy-to-grow sedge in the landscape, provided you give it what it requires, namely, full sunlight. I (Eickhoff) made the mistake of planting ʻahaniu in an open area, not paying attention to the hame which was slowly creating a dense canopy above it. The shading eventually killed most of the plants beneath it, including the ʻahaniu! Therefore, ʻahaniu needs a lot of sunlight to thrive.

As far as substrate, it does not appear to be picky at all as long as it is given sufficient sunlight. I have used a free-draining mix that includes black cinder and/or perlite in containers and for landscape plants with great results.

Though extra nutrient requirements seem to be low, when I used a kelp extract for foliar feeding once a month, I noticed a significant difference, with more foliage growth and a more vibrant blue-green color within a few months.

Pests and Diseases

I (Eickhoff) have not noticed any significant pests or diseases affecting ʻahaniu.

Uses

Ancient Hawaiian

ʻAhaniu was used for tying (see Hawaiian Name below) [Neal 1965].

Modern

Flowering stalks can be used in dry arrangements [Neal 1965].

Special Features and Information

General

The genus Machaerina, a member of the Sedge Family (Cyperaceae), comprised of approximately 85 species. There are two Machaerina species native to the Hawaiian Islands. The USDA Natural Resources Conservation Service recognizes three subspecies of Machaerina mariscoides: subsp. colpodes, subsp. mariscoides, and subsp. meyenii, which is endemic to Hawaiʻi. The other native is Machaerina angustifolia, which is indigenous to Hawai‘i, may also have good potential as a landscape plant since it is found at lower elevations.

Hawaiian Name

The early Hawaiians named this plant ʻAhaniu, meaning "coconut sennit" [Neal 1965]. Sennet is a type of cordage made by plaiting or braiding strands of leaves or fiber [WikipediA;Sennit]. Coconut (niu) fiber from the husks was often used, and was important in attaching the ʻama (outrigger float) to the hull of the waʻa (canoe), as well as securing stones to war-club handles and erecting hale (houses) [WikipediA;Sennit].

ʻUki is a name used for some native plants with strap-like leaves (Cladium jamaicense, Dianella sandwicensis, Machaerina spp.) [Hawaiian Dictionaries].

Etymology

The generic name Machaerina is derived from the Latin machaera, a bent dagger or sword, and -ina, a feminine suffix, which in this case is diminutive, referring to the shape of the leaves of some species [Wagner et al. 1990]. The specific epithet mariscoides is from the Latin Mariscus, a genus in Cyperaceae, with the suffix -oides, like or resembling, in reference to this species resemblance to the sedge Mariscus [Gledhill 2008]. The subspecific epithet meyenii was named after Franz Julius Ferdinand Meyen (1804–1840), a Prussian physician and botanist [WikipediA;Franz Meyen].

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