Introduction & Discovery

Lygodium articulatum, known in Te Reo Maori as mangemange, is New Zealand's sole representative of the climbing fern genus and one of the most distinctive pteridophytes in the Aotearoa flora. Like all members of Lygodium, its fronds are indeterminate: each rachis grows from a continuously active apical meristem that twines around surrounding vegetation, climbing through the forest understory and into the lower canopy. What appears to be a slender vine is, in fact, a single leaf, a biological marvel that defies the conventional image of a fern as a ground-hugging rosette of finite fronds. In New Zealand's podocarp-broadleaf forests, mangemange drapes the understory with curtains of delicate, lacy foliage, its wiry rachises threading through the crowns of tree ferns, coprosma, and mahoe, sometimes extending more than 15 metres from the terrestrial rhizome. The species epithet 'articulatum' refers to the conspicuous joints or articulations along the rachis at the nodes where paired pinnae emerge, giving the climbing axis a segmented, almost bamboo-like appearance under close inspection. This feature distinguishes L. articulatum from most other climbing ferns, in which the rachis transitions more smoothly between nodes. Ecologically, mangemange plays a significant role in New Zealand forest dynamics: its tangled climbing fronds create habitat structure exploited by invertebrates, small lizards, and epiphytic bryophytes, while its ability to bridge canopy gaps assists in the colonization of light wells by other species. The Maori people historically used the tough, flexible rachises of mangemange for weaving and binding, recognizing the extraordinary tensile strength of this plant's leaf axis. In cultivation, L. articulatum is less commonly grown than L. japonicum or L. microphyllum, partly because its requirement for mild, humid, frost-free conditions limits its range in temperate gardens, and partly because plant material is rarely available outside New Zealand. For growers in warm, humid climates or those with heated conservatories, however, mangemange offers an elegant and unusual climbing fern with deep cultural resonance and ecological significance.

Discovery & Naming

Lygodium articulatum was first described by the Scottish botanist Robert Brown in his Prodromus Florae Novae Hollandiae (1810), based on material collected during early botanical exploration of the Australasian region. Brown recognized the articulate rachis as a distinguishing feature and assigned the specific epithet accordingly. The species was well known to Maori, who called it mangemange and employed its tough rachises for practical purposes long before European botanical documentation. During the intensive botanical exploration of New Zealand in the nineteenth century by collectors including William Colenso, Thomas Kirk, and John Buchanan, the distribution and ecology of mangemange were thoroughly documented. Kirk's The Students' Flora of New Zealand (1899) provided a comprehensive treatment. The family placement of Lygodium has been refined through molecular phylogenetics: the Pteridophyte Phylogeny Group classification of 2016 (PPG I) placed the climbing ferns in their own family, Lygodiaceae, within the order Schizaeales, one of the earliest-diverging lineages of leptosporangiate ferns. Approximately 25 to 40 living Lygodium species are recognized worldwide, and L. articulatum represents the southernmost reach of the genus, isolated in New Zealand since the Oligocene or earlier.

Frond Morphology

The frond architecture of Lygodium articulatum exemplifies the genus-defining strategy of indeterminate rachis growth while displaying species-specific features that set it apart from its congeners. Each frond originates from a short, erect stipe 5 to 15 cm long, transitioning into the twining rachis that constitutes the climbing axis. The rachis is wiry, 1 to 2 mm in diameter, green to dark brown at maturity, and displays the diagnostic articulations at each node. These joints are visible as slight constrictions or swellings where the vascular trace branches to supply each pair of pinnae, and they represent points of potential abscission under mechanical stress, allowing sections of the climbing frond to break away without killing the entire structure. The rachis twines counter-clockwise (viewed from above) around vertical supports, with coiling periods of 2 to 5 cm. Primary pinnae emerge in opposite pairs at nodes spaced 5 to 20 cm apart along the rachis. Each primary pinna is borne on a petiolule 1 to 3 cm long and is itself divided once to twice pinnately. Sterile pinnules are ovate to lanceolate, 2 to 5 cm long and 1 to 2.5 cm wide, with entire to shallowly crenate margins and a thin, herbaceous texture. The venation is free-forking and dichotomous, visible as a delicate network against transmitted light. Fertile pinnules are contracted and narrower than sterile ones, bearing marginal sorophores 3 to 6 mm long, each carrying a double row of sporangia protected by a reflexed false indusium. The overall effect of a well-established plant is a feathery curtain of paired pinnae suspended along a near-invisible wiry axis, creating one of the most graceful climbing structures in the fern world. The rachis cross-section reveals a single C-shaped vascular bundle surrounded by sclerenchyma, confirming its leaf identity despite vine-like behaviour.

Native Range & Distribution Map

Distribution map showing the native range of Lygodium articulatum.

Biology & Frond Morphology

Lygodium articulatum grows from a short, creeping to suberect rhizome 3 to 6 mm in diameter, clothed in dark brown, narrowly lanceolate scales 2 to 4 mm long. The rhizome branches sparingly, producing fronds at irregular intervals and anchoring itself in the upper layers of forest-floor humus with fine, dark adventitious roots. Unlike the rhizome systems of invasive Lygodium species such as L. japonicum and L. microphyllum, which can form dense, deeply penetrating mats, the rhizome of L. articulatum is modest in extent, reflecting the species' slower growth rate and non-invasive character. The vascular anatomy of the rhizome is a protostele typical of the Schizaeales, with centrally positioned xylem surrounded by phloem and an outer cortex of parenchyma and sclerenchyma. Photosynthesis occurs primarily in the pinnules, which are adapted to the low to moderate light intensities of the forest understory and sub-canopy layers. Chloroplast density is high in the palisade mesophyll, enabling efficient carbon fixation at light levels of 10 to 30 percent of full sunlight. The climbing strategy allows the plant to position photosynthetic tissue at varying heights within the forest profile, optimizing light capture as conditions change with canopy dynamics. Mycorrhizal associations with arbuscular mycorrhizal fungi enhance nutrient uptake in the typically acidic, humus-rich soils of New Zealand podocarp forests. Growth rates in the wild are moderate: rachis elongation of 2 to 8 cm per day during the warm season (November to March in the Southern Hemisphere), producing fronds that may reach 10 to 20 metres over several growing seasons. The species is evergreen in frost-free locations but may lose upper frond portions during cold snaps, regenerating from lower nodes and from the rhizome in spring.

Spore Dispersal

Lygodium articulatum reproduces sexually via wind-dispersed spores produced on specialized fertile pinnules located on the upper portions of climbing fronds. Fertile pinnae are typically borne above sterile pinnae on the same rachis, positioning sporangia in the better-ventilated, more light-exposed upper canopy layers where air currents facilitate dispersal. Each fertile pinnule bears 4 to 10 marginal sorophores, finger-like projections 3 to 6 mm long, each carrying a double row of sporangia on the abaxial surface beneath a reflexed false indusium. The sporangia are leptosporangiate with an oblique annulus of 14 to 18 thickened cells that generates the catapult mechanism for spore ejection. Each sporangium contains approximately 128 to 256 spores. The spores are trilete, roughly tetrahedral, 55 to 75 micrometres in diameter, with a verrucate to granulate surface texture. They are sufficiently light for long-distance wind dispersal, and the elevated release point from the climbing frond greatly enhances dispersal range compared to ground-level ferns. Spore release occurs primarily during dry, breezy conditions in late summer and autumn (February to May in New Zealand). Germination on suitable moist, shaded substrates produces bisexual, heart-shaped prothalli approximately 5 to 8 mm across, which develop both antheridia and archegonia, enabling self-fertilization. Sporophyte development from the fertilized archegonium typically takes 3 to 6 months before the first climbing frond is produced. In New Zealand forests, natural recruitment appears adequate to maintain populations, though habitat fragmentation may limit gene flow between isolated forest remnants.

Reproduction & Propagation

Lygodium articulatum propagates by two methods: rhizome division and spore culture. Rhizome division is the more practical approach for home growers. In early spring, when new growth is commencing, carefully lift the plant and expose the rhizome system. Identify sections with at least 5 cm of rhizome bearing 2 to 3 frond buds and a healthy complement of roots. Cut cleanly with a sterilized blade, dust cut surfaces with powdered sulfur or cinnamon to reduce infection risk, and replant divisions immediately in pre-moistened substrate at the same depth as the original planting. Water thoroughly and maintain high humidity (70 to 80 percent) for 3 to 4 weeks while roots re-establish. Expect some frond loss during the establishment period; new climbing fronds should emerge within 4 to 6 weeks if temperatures are above 18°C (64°F). Spore propagation follows the general Lygodium protocol. Collect fertile pinnae bearing mature, dark brown sorophores in late summer or autumn. Place in a paper envelope for 48 to 72 hours to allow sporangia to dehisce and release spores. Prepare sterile sowing medium: finely sieved sphagnum peat and perlite (1:1), sterilized by microwave treatment for 3 minutes. Scatter spores thinly over the moist surface without covering. Seal the container in clear plastic and place under bright indirect light or LED grow lights at 20 to 24°C (68 to 75°F). Prothalli should appear within 10 to 21 days as a green film. Maintain sealed conditions for 2 to 3 months, during which young sporophytes develop. Prick out sporophytes at the 3 to 4 frond stage into individual pots with a small support stake. Spore-grown plants reach climbing size within 12 to 18 months.

Cultivation & Substrate

Growing Lygodium articulatum outside its native New Zealand requires replicating the mild, humid, frost-free conditions of warm-temperate Australasian forest. The species is best suited to outdoor cultivation in USDA zones 10 to 11, or to conservatory and greenhouse culture in cooler climates. Provide a sturdy climbing support: a wire trellis, mesh panel, or thin-diameter poles 1 to 4 cm wide, positioned vertically to allow the twining rachis to gain height. In a greenhouse, a wall-mounted wire grid 2 to 3 metres tall makes an excellent support system. Light should be bright but indirect, simulating the dappled sub-canopy conditions of New Zealand forest. Avoid direct midday sun, which scorches the delicate pinnules. In a greenhouse, 40 to 60 percent shade cloth over the roof provides appropriate light levels. Temperature management is critical: maintain 12 to 28°C (54 to 82°F) year-round, with optimal growth at 18 to 24°C (64 to 75°F). The species tolerates brief dips to 5°C (41°F) but sustained temperatures below 8°C (46°F) stall growth and cause frond damage. Humidity should be maintained at 60 to 80 percent; in heated greenhouses, this may require regular misting, humidity trays, or fogging systems. The substrate should be humus-rich and well-drained: a mix of two parts leaf mould or composted bark, one part peat or coco coir, and one part perlite provides the acidic, moisture-retentive medium the species prefers. Water consistently during the growing season to keep the root zone evenly moist; reduce watering in winter if temperatures drop and growth slows. Feed with a half-strength balanced liquid fertilizer (e.g., 10-10-10) monthly during the active growing season (spring through autumn). Sourcing plant material is the greatest challenge: L. articulatum is rarely offered by international nurseries, and New Zealand biosecurity regulations restrict plant export. Spore exchanges through pteridological societies or acquisition from botanical gardens with established collections may be the most viable routes.

Common Mistakes to Avoid

The most frequent error in cultivating Lygodium articulatum is insufficient humidity. Unlike the more robust L. japonicum, which tolerates humidity as low as 50 percent, L. articulatum hails from consistently humid New Zealand forests and suffers frond desiccation and marginal browning when relative humidity drops below 55 percent for extended periods. Heated indoor environments in temperate climates are particularly problematic, as central heating can reduce humidity to 20 to 30 percent in winter. The second common mistake is exposing the plant to frost. Even brief exposure to temperatures below minus 2°C (28°F) can kill the climbing fronds and damage the rhizome, and unlike L. japonicum, which regenerates reliably from deeply dormant rhizomes after hard freezes, L. articulatum lacks equivalent cold hardiness. A third error is failing to provide climbing support; without vertical structures to twine around, the rachis tangles into an unmanageable snarl, becomes stressed, and produces sparse, poorly developed pinnae. Fourth, some growers overwater the substrate, creating waterlogged conditions that promote rhizome rot. The substrate should be consistently moist but never saturated. Fifth, over-fertilization with concentrated fertilizer solutions burns the fine root system and causes pinnule scorch. Always dilute to half strength and fertilize only during active growth. Finally, placing the plant in deep shade reduces photosynthetic output below the threshold needed to sustain vigorous climbing growth, resulting in etiolated, sparse fronds that fail to develop the graceful curtain effect characteristic of healthy specimens.

Seasonal Considerations

In its native New Zealand habitat, Lygodium articulatum grows year-round in frost-free areas, with peak growth during the warm season from November through March. In cultivation, seasonal care should follow the local climate pattern. During spring and summer (the primary growth period), ensure consistent moisture, maintain temperatures of 18 to 25°C (64 to 77°F), provide 12 to 14 hours of bright indirect light, and fertilize monthly with half-strength balanced liquid fertilizer. This is when rachis elongation is fastest, potentially 3 to 8 cm per day in warm, humid conditions. Monitor climbing supports and redirect or prune fronds that outgrow their allocated space. During autumn, growth slows as temperatures moderate and day length decreases. Reduce fertilization to every 6 to 8 weeks, then cease entirely by mid-autumn. Continue watering but extend intervals slightly as transpiration decreases. This is a good time to remove any damaged or dead frond material and inspect for pests. In winter, the plant enters a period of reduced activity. If grown in a greenhouse, maintain minimum temperatures of 10 to 12°C (50 to 54°F). Water sparingly, allowing the top centimetre of substrate to dry slightly between waterings. Do not fertilize during winter. If some frond sections die back during cold weather, leave them in place until spring when new growth begins, then prune away dead material to make room. In tropical and subtropical outdoor settings (zones 10 to 11), the species may grow nearly continuously, with only a slight slowing during the coolest months. In these conditions, reduce fertilization in the cooler period but maintain regular watering. Resume full growing-season care when temperatures consistently exceed 18°C (64°F) and day length increases.

Diseases & Pests

Lygodium articulatum is generally pest- and disease-resistant when grown under appropriate conditions. The most common problem is rhizome rot caused by Pythium or Phytophthora species, which occurs when the substrate is chronically waterlogged or when drainage is poor. Symptoms include failure to produce new fronds, softening and browning of the rhizome, and a sour odor when the rhizome is examined. Prevention through well-drained substrate and careful watering is far more effective than treatment; if caught early, cutting away infected tissue, repotting in fresh substrate, and reducing watering may save the plant. Scale insects occasionally colonize the wiry rachis, appearing as small brown or white limpet-like crusts. They are rarely present in sufficient numbers to cause serious damage and can be removed by wiping with isopropyl alcohol on a cotton swab or applying horticultural oil at 1 to 2 percent concentration. Mealybugs and aphids are uncommon on Lygodium but may appear in greenhouse culture; treat with insecticidal soap or neem oil. Botrytis (gray mold) can develop on dead or dying frond material in humid, poorly ventilated conditions, so prompt removal of dead tissue and adequate air circulation are important preventive measures. Foliar nematodes are occasionally reported on Lygodium species, causing irregular brown patches bounded by veins; remove and destroy affected pinnae and avoid overhead watering that splashes from infected to healthy tissue.

Indoor Growing & Terrariums

Growing Lygodium articulatum indoors requires a conservatory, sunroom, or large greenhouse rather than a typical living room setting. The species needs vertical climbing space (minimum 2 to 3 metres of trellis height), bright indirect light, warmth (18 to 25°C or 64 to 77°F), and humidity of 60 to 80 percent, conditions difficult to achieve in standard domestic rooms. An east- or north-facing conservatory in the Southern Hemisphere (or east- or south-facing in the Northern Hemisphere) provides ideal light. Install a wall-mounted wire trellis or tensioned vertical wires spaced 10 to 15 cm apart for the rachis to twine around. The climbing fronds create a graceful, lacy screen that serves both ornamental and privacy functions. Pot in a container of at least 15 to 25 litres with excellent drainage holes, using a humus-rich mix of leaf mould, coco coir, and perlite. Water when the top centimetre of substrate feels dry, typically every 2 to 4 days in summer and weekly in winter. Maintain humidity by grouping with other tropical plants, using pebble trays, or running a room humidifier. Feed monthly during the growing season with dilute liquid fertilizer. The primary maintenance task is pruning: fronds that reach the top of the trellis and begin growing along the ceiling should be cut cleanly with sterilized scissors at a convenient point along the rachis. The plant responds by producing new fronds from the rhizome. For growers without conservatory space, a large, heated terrarium cabinet (1.5 metres or taller) with built-in grow lights and humidity control could house the species, though frequent pruning would be necessary. This is not a windowsill plant or a desk fern. Its unique appeal lies entirely in the climbing habit, and any indoor setup that does not provide vertical space and appropriate climate control wastes the species' most distinctive characteristic.

Terrarium Setup

Lygodium articulatum is poorly suited to conventional terrarium culture due to its vigorous climbing habit and indeterminate frond growth. A single frond can extend several metres, rapidly outgrowing any standard terrarium enclosure. However, a very large paludarium or display vivarium exceeding 1.5 metres in height, fitted with internal climbing supports (moss poles, wire trellises, or tension-strung fishing line), could theoretically house a young specimen for a limited period. In such a setup, use a substrate of sphagnum moss mixed with perlite and fine orchid bark (1:1:1) over a drainage layer of expanded clay aggregate. Maintain water in the drainage reservoir to provide passive humidity of 70 to 85 percent, with the substrate itself kept moist but not waterlogged. Temperatures of 18 to 25°C (64 to 77°F) and bright indirect light from full-spectrum LED fixtures providing 4,000 to 8,000 lux at the foliage level are appropriate. Ventilation is essential to prevent stagnant air and fungal issues; a partially open top or small circulation fan running intermittently achieves adequate air exchange. The plant will need regular pruning as climbing fronds reach the top of the enclosure, cutting the rachis cleanly with sterilized scissors. This stimulates the rhizome to produce new fronds. For growers seeking a fern with a climbing or trailing habit suitable for standard terrariums, consider Selaginella species, Microgramma, or Pyrrosia piloselloides instead, which remain compact enough for enclosed culture.

Landscape & Garden Use

Lygodium articulatum can be used in the garden wherever its hardiness and habitat preferences are matched. Ferns are classic choices for shaded borders, woodland gardens, stumperies, rockeries, stream-side plantings, and ground-cover under trees.

Landscape Tips

• Companions: Hostas, Astilbe, Heuchera, Tiarella, Epimedium, hellebores, snowdrops and other shade-tolerant perennials are classic partners.
• Soil preparation: Incorporate leaf mould or composted bark to improve moisture retention and mimic a forest floor.
• Mulching: A 3–5 cm mulch of chipped bark or leaf litter protects the rhizomes, conserves moisture, and slowly releases nutrients.
• Watering: Establish new plantings with regular deep watering during the first growing season; most hardy ferns need only occasional supplemental irrigation once established.

Conservation & Collector Notes

Lygodium articulatum is not currently listed as threatened in New Zealand under the Department of Conservation's threat classification system. The species remains relatively common in suitable forest habitats throughout the North Island and northern South Island. However, long-term population trends are linked to the health of New Zealand's native forest, which has been significantly reduced since human settlement. Continued deforestation, possum and deer browse damage to forest understory, and habitat fragmentation all represent indirect threats. The species does not face the invasiveness concerns that plague L. japonicum and L. microphyllum in the Americas, as it is well-behaved within its native range. Climate change may expand suitable habitat southward on the South Island as temperatures warm but could also alter the humidity and frost patterns that define its current range limits.