Ripogonum scandens
Ripogonum scandens, commonly known as supplejack and kareao, is a species of climbing forest vine in the family Ripogonaceae. It is endemic to New Zealand. Its range mainly covers the North and South Islands, it also occurs on some offshore islands. Red globe-shaped fruits, which hang from the oppositely arranged leaves, are eaten and dispersed by birds. These fruits are edible, and so are the newly formed shoots at the end of the vines.
The species was first described by Johann Reinhold Forster and Georg Forster in 1776. The genus Ripogonum, was originally considered to be part of the family Smilacaceae or Liliaceae, but in 1985 was reclassified as the sole genus in the family Ripogonaceae. R. scandens was valued by Māori and European settlers, primarily for the stems that were valued for their length, strength, and flexibility. In 2023, the conservation status was assessed as "Not Threatened" in the New Zealand Threat Classification System.
Description
Ripogonum scandens is an evergreen climbing forest vine, reaching lengths of up to long. The rhizomes are stout, woody, and in diameter. The stems can be several metres long, about in diameter, seldomly branched, almost black in colour, with nodes about apart. Leaves are mostly arranged opposite to each other, usually 55–160 × 20–60 mm long, variably green in colour, coriaceous in character, narrow-ovate to oblong in shape.Flowering typically occurs in December and January. The petioles are about long. Its inflorescences are long. Its pedicels are about long. Its spreading tepals are green in colour. Its filamentous stamens are about long. Its anthers are greenish to yellow in colour, linear-oblong in character, and about 3.0–5.0 × 1.0–1.5 mm long. Its ovaries are globe-shaped, about in diameter. Fruiting typically occurs from March onwards. Fruits are also globe-shaped, bright red in colour, in diameter; the pericarps are thin and fleshy. R. scandens has a diploid chromosome count of 22.
Taxonomy
Classification
Ripogonum scandens is a species of plant in family Ripogonaceae. Ripogonum scandens is the sole member of the genus Ripogonum in New Zealand, with several members of the genus found in Australia and New Guinea. The taxonomic placement of the species is debatable, and has been formerly placed in the family Smilacaceae or Liliaceae. In 1985, a study established the family Ripogonaceae and placed the sole genus Ripogonum in it. The glabrous foliage and other details of the plant, are comparable to those of R. danesii and R. papuanum, found in Australia and New Guinea, respectively. Fossil leaves of Ripogonum from the Manuherikia Group are indistinguishable from the extant species, R. scandens. Fossil leaves of Ripogonum have been discovered in Patagonia, Argentina.In 1776, the species and the genus Ripogonum was first described by the German naturalists Johann Reinhold Forster and Georg Forster in the second edition of their Characteres Generum Plantarum with Ripogonum scandens designated as the type species.
Etymology
The etymology of R. scandenss genus name, Ripogonum, is unclear. One possibility is that it might come from the Greek rhipos, meaning 'wickerwork', and gonu meaning 'jointed', in reference to the cane-like stems. Another possibility suggests that the genus name could mean "osier with knees". The specific epithet, scandens, meaning 'climbing', in reference to the climbing habit of the species. The common English language name supplejack is used to describe tough, woody climbing plants, and is a name used for numerous unrelated plants. The Māori language name kareao is of uncertain etymology, but the name pirita has cognates in other Polynesian languages, typically 'pilita', which is a word used to describe the wild yam.Ripogonum scandens was one of the first native plants to receive a common name from Europeans, known as 'supplejack', which was first coined in 1773 during Cook's second voyage to New Zealand. The etymology of the word is uncertain, but it is possible that a member of his crew named it 'supplejack', a 'jack' being a sailor. The roots of the plant had some medicinal purposes to settlers, and the plant was sometimes termed 'bush sarsaparilla'.
Ecology
Ripogonum scandenss fruits appear to be dispersed by fruit-eating animals, including numerous bird species. The kererū and blackbirds are two bird species that consume fruits of R. scandens. The fruits are also eaten by the tūī, and are one of the main winter food sources for the North Island kōkako. In addition to the fruits, kererū are also known to feed on adult leaves.Ripogonum scandens is pollinated by either insects or the wind. MacMillan noted that some flowers have underdeveloped ovaries, which allows self-pollination.
Ripogonum scandens plays host to two species of aphids from the genus Aulacorthum. Several moths have been identified as hosts on R. scandens, including Ctenopseustis obliquana, a common species in New Zealand, the larvae can eat the stems, leaves, flowers and fruit. Epalxiphora axenanas larvae feed under the cataphylls and chew the tissue and stem. Oemona hirta is also hosted on R. scandens. The fruits of R. scandens, and other parts of the plant, are eaten by cattle, deer, feral pigs, possums, and rats.
A plant pathogen, Peniophora sacrata, is hosted on R. scandens. New Zealand botanist G. H. Cunningham, recorded several fungi species of Thelephoraceae and two species of Polyporaceae that are saprophytic on dead stems of the species. Other fungi species and genera include, Acrogenotheca elegans, Septobasidium and Wallrothiella. Research by MacMillan suggests that in December and January, R. scandenss tips can grow an average of a day.
Distribution
Ripogonum scandens is endemic to New Zealand. Its range covers the North and South Islands. It also occurs on the offshore Stewart and Chatham Islands. R. scandens generally occurs throughout the North Island. In the South Island, R. scandenss range mainly covers the western coast of the island, with several scattered distribution areas on the eastern coast of the island. Throughout Marlborough, Canterbury and Otago, the occurrence of R. scandens is sparingly found in relics of old-growth forests and is mainly found on peninsulas such as Kaikōura, Banks, and Otago. Other inland populations near Winton and Geraldine have also been reported to be present. It is found in abundance on Stewart Island. R. scandenss conservation status was assessed in 2023 in the New Zealand Threat Classification System as "Not Threatened".Habitat
Ripogonum scandens is typically found in coastal to montane forests. R. scandens tends to be most common in forests that are dominated by hardwoods and podocarps. It is commonly associated with beech in Fiordland. R. scandenss maximum altitudinal ranges have been recorded as and in the North and South Islands, respectively. R. scandens will inhabit a wide range of soil types such as loam, pumice, and alluvial soils. The plant is also known the plant is able to withstand swampy forest conditions, where the soil can be occasionally flooded. R. scandens grows in both sunny and shady areas.Uses
In Māori culture
Ripogonum scandens is present in Māori mythology, in which, the vines are considered to be the tail of the god of eels, Tunaroa. The origin of this came from revenge for disrespecting the demigod Māui's wife. Therefore, Māui ambushed Tunaroa and killed him. Tunaroa's blood coloured birds and plants red, his body became many eel and fish species, and the tip of his tail became R. scandens, which could be used by people to create traps for eels. Other Māori traditions describe R. scandens as a plant created by Patupaiarehe, supernatural beings, as a defence for their forest homes. R. scandenss use in construction was also valued by Māori people for house-building and waka construction. The vines are also a traditional building material to create traps for crayfish, eels, kōkopu and kiore.Ripogonum scandens has also had some medicinal uses for Māori people, such as the roots being used to treat multiple diseases. There are also records of decoctions that were made to procure abortions. The fruits are edible, although most of the fruit consists of seed, the fruits have been described as "quite tasteless" by New Zealand botanist and horticulturalist Lawrie Metcalf. The young shoots are a more important food source, they have been nicknamed 'bush asparagus' in English, and they taste like green beans.
In European culture
Ripogonum scandens was valued by Māori and European settlers, primarily for its stems which were valued for their length, strength, and flexibility. The greatest value of R. scandens was perhaps its use in construction; the woody stems have proven to be useful in the making of baskets, binding together fences, canes, canoes, eel traps, fenders, houses, huts, ladders, rafts, sheep hurdles, walking sticks, and so forth.Early European settlers also noted the intertwining characteristic of R. scandens, including the British explorer James Cook, who observed the plant while anchored in Dusky Sound. The intertwining characteristic is considered by many authors to be an inconvenience for movement in forests. The tangling characteristic of the vines has also been used to assist people descending cliff faces, which has been experimented with by the explorers Thomas Brunner and Charles Heaphy.
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