Native Plants of Hawai‘i - Sicyos pachycarpus

Sicyos pachycarpus

Cucurbitaceae or Gourd family

Synonyms: Sicyocarya atrimaculata, Sicyocarya rostrata, Sicyos laysanensis, Sicyos microcarpus, Sicyos microcarpus var. ewaensis, Sicyos microcarpus var. forbesii, Sicyos microcarpus var. haleakalaensis, Sicyos microcarpus var. kalaupapaensis, Sicyos microcarpus var. kamoaensis, Sicyos microcarpus subsp. kanepuuensis, Sicyos microcarpus var. kauensis, Sicyos microcarpus var. kilaueaensis, Sicyos microcarpus var. koeleensis, Sicyos microcarpus var. koloaensis, Sicyos microcarpus subsp. lanaiensis, Sicyos microcarpus var. lanaiensis, Sicyos microcarpus subsp. laysanensis, Sicyos microcarpus var. laysanensis, Sicyos microcarpus var. meeboldii, Sicyos microcarpus var. obovoideis, Sicyos microcarpus var. oniniensis, Sicyos microcarpus var. paneensis, Sicyos microcarpus var. pohakeaensis, Sicyos microcarpus subsp. puberulus, Sicyos microcarpus var. trilobata, Sicyos microcarpus var. woolfordii, Sicyos niger, Sicyos nihoaensis, Sicyos remyanus

ʻĀnunu

Kūpala (see Hawaiian Name below)

Natural Range & Environment

Sicyos pachycarpus is endemic to Laysan (Kauō), Nīhoa, and all the main Hawaiian Islands [Flora of the Hawaiian Islands]. It is widespread in coastal native and non-native herblands, shrublands, and forests, typically growing in sand, coralline substrate, or thin clay soil from near sea level to 900 m (2,953 ft) [Wagner et al. 1990]. However, ʻānunu can also be found, and is sometimes even common, on lava-dominant substrate at higher elevations, such as in upland leeward East Maui (see Forest & Kim Starr photograph below).

ʻĀnunu produces male (left) and female (right) flowers on the same plant, which can vary in size. Therefore, don't use the size difference seen here to distinguish between male and female flowers (photograph courtesy of Forest & Kim Starr CC BY 3.0 US). Rather, look at how the flowers are clustered, with female flowers arranged in a ball, while male flowers are positioned on a branching stalk. Pollinated female flowers quickly swell into a fused ball of first green (unripe) fruits that turn brown to black when ripe (photograph courtesy of Joel Lau ©). ʻĀnunu leaf shape and size can vary dramatically between plants and populations, with the only constant feature being that all ʻānunu leaves are paper thin (photograph of two very different leaf shapes courtesy of Joel Lau ©).

In urban environments, ʻānunu will use its corkscrew tendrils to climb on just about anything nearby. During the wet season, hundreds to thousands of ʻānunu can rapidly and completely cover all the native or non-native vegetation in an area (photograph courtesy of Forest & Kim Starr CC BY 3.0), only to die and disappear from the area when dry weather returns (photograph courtesy of Kevin Faccenda CC BY 4.0).

Description

Sporobolus

Growth Requirements

General

To be honest, I (Koebele) don't know if anyone will ever be very interested in growing ʻānunu as part of their landscape since it is short-lived and extremely aggressive, quickly covering any nearby plants or structures. Instead, it's greatest utility, and where I have used it, is in native lowland restoration sites recently-cleared of non-native flora that have a seasonal rainfall pattern (e.g., wet winters and dry summers). There, ʻānunu does a good job of smothering alien weeds before they can mature and produce seeds; you just need to scatter a lot of ʻānunu seeds thoughout the site. While ʻānunu isn't 100% effective at this job, you will have far fewer non-native weeds to pull out during and at the end of the wet season if you use it. In addition, the ʻānunu will seed, die out, and essentially disappear when dry weather comes. Unfortunately, when you do start filling your site with other native plants —it typically takes two or three wet seasons to deplete the non-native soil seed bank —you will need to quickly remove any ʻānunu trying to cover up your native plantings. In summary, consider using ʻānunu rather than herbicides to rid a restoration site filled with a large soil seed bank of non-native weeds.

ʻĀnunu grows most quickly in a site with full sunlight for all or most of the day. However, it will survive (and wild plants frequently start out) in shaded areas. Essential to its growth is moist soil (or root access to underground water) since without it ʻānunu quickly wilts, dries out, and dies. Fertilizers are not neccessary for this already fast-growing herbaceous vine. ʻĀnunu can tolerate extreme heat and strong winds provided its roots have easy access to moisture but is generally intolerate of waterlogged soils or media.

I have never tried to cultivate ʻānunu outsite of a restoration setting where it naturally dies during the dry weather of summer. However, Lilleeng-Rosenberger [2005] recommends removing cultivated Sicyos flowers early and keeping the plant well-watered to prolong its life.

Pests and Diseases

Aphids sometimes infest ʻānunu. Also, snails and slugs will consume young plants and portions of older plants. Refer to the Pests & Diseases page for ways to deal with these pests. Curiously, stinkbugs are attracted to ʻānunu, but appear to cause little damage. These can be removed by hand (of course, while wearing gloves).

Uses

Ancient Hawaiian

Both

Modern

Special Features and Information

General

Cucurbitaceae is a plant family with about 965 species within 101 genera, found in temperate and tropical areas around the world. Most are fast-growing annual herbs or vines, with many being important food plants (e.g., squash, pumpkin, watermelon, cucumber, cantaloupe) that are frost-sensitive [WikipediA;Cucurbitaceae]. Sicyos is the only native member of this family found in Hawai‘i [Flora of the Hawaiian Islands].

There are currently (2026) 14 endemic species of Sicyos in Hawai‘i, collectively found in a wide range of habitats; most are annuals [Flora of the Hawaiian Islands; Wagner et al. 1990]. While one can argue that Hawaiian Sicyos are not as attractive as some other species-rich endemic Hawaiian plant genera such as Cyanea and Coprosma, they are still quite amazing because of their endemic diversity. Additionally, unlike many Sicyos species outside Hawai‘i, Hawaiian Sicyos lack the hooked spines on their fruits which aid in the seed dispersal of non-Hawaiian species [Sebastian et al. 2012].

Hawaiian Name

ʻĀlunu, a variant spelling of ʻĀnunu, means "greedy, covetous, rapacious [Pukui & Elbert 1986]. Might this be an indirect reference to ʻānunu's frequent behavior of covering up nearby plants?

Several sources, such as Wagner et al. [1990] and Plants of Hawai‘i, list the name Kūpala for Sicyos pachycarpus. However, Joel Lau claims that the name Kūpala has apparently been wrongly applied to Hawaiian Sicyos taxa. And that Kūpala is actually some kind of morning glory (Ipomoea sp.) with a tuberous root that occurred or possibly still occurs in dry regions of Hawai‘i and was used as a famine food by the Hawaiians. Pukui & Elbert [1986] define Kūpala as both a name for Sicyos pachycarpus and for "A wild sweet potato or morning-glory with enlarged tuber, eaten in time of famine." Unfortunately, I (Koebele) lack the needed expertise to comment further on this disagreement.

Etymology

Sicyos originates from the Ancient Greek word, sī́kyos (σίκυος), used by Theophrastus (c. 371– c. 287 BC), a philosopher and naturalist often considered the "father of botany" [WikipediA;Theophrastus], for a cucumber [Gledhill 2008]. The species name, pachycarpus, comes from the Greek words, pachys, meaning "thick," and karpos, meaning "fruit" [Gledhill 2008; PlantZAfrica].

BPK