Nephrolepis flexuosa
Biostatus
Native
Category
Vascular
Structural class
Ferns
Flower colours
No flowers
Detailed description
Rhizomes short, erect, stoloniferous. Stolons without tubers. Fronds pinnate, at first erect but tending to droop with age (0.1)–0.8–1–(1.5) m × (10)–20–(50) mm (including stipes); yellow-green to dark green, narrowly lanceolate, gradually tapering toward apex; rachis bearing subulate scales, margins fringed with many short hair-like processes. Pinnae in 50–60–(80) or more pairs, deltoid-oblong or oblong, subsessile, closely adjacent and overlapping rachis, often with an enlarged basal auricle. Sterile pinnae (5)–10–15–(25) × (4)–6–(10) mm; margins entire to subentire, crenulate or serrated towards apex. Fertile pinnae distinctly shorter, margins crenulate (rarely serrated). Sori submarginal, indusia reniform, opening toward pinna apex.
Similar taxa
Frequently confused with the naturalised and highly aggressive N. cordifolia, from which it is easily distinguished by its non-tuberous habit. Both species also differ by their chromosome number, 2n = 82 in N. cordifolia and 2n = 164 in N. flexuosa, and by their spore morphology and size. N. flexuosa tends to have narrower more gracile fronds which are typically drooping, while those of N. cordifolia are wider, stouter and invariably rigidly erect.
Distribution
Indigenous. New Zealand: Kermadec Islands (Raoul Island), North Island (Kawerau south to Rotorua Lakes District to Lake Taupō / Taupō Moana, reaching its southern limit at Tokaanu near Tūrangi). Also Norfolk Island, Lord Howe Island, Fiji, Cook Islands (Rarotonga). This species may also be in Australia, Samoa and Sri Lanka and it is probably wide ranging throughout the Indian Ocean and Pacific Ocean.
Habitat
Abundant in coastal forest and scrub on Raoul Island, otherwise in New Zealand confined to the North Island where it is only known from active geothermal fields from about Kawerau south to the Rotorua Lakes District to Lake Taupo, where it reaches a world southern limit at Tokaanu near Turangi.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | At Risk – Naturally Uncommon | Qualifiers: DPR, PD, RR, SO
Threats
Very common on Raoul Island. In the North Island it is confined to active geothermal fields where it can be locally common, though more often than not it is scarce. At least one population near Kawerau is threatened by the spread of N. cordifolia which has become well established at that site. Many populations are threatened by the spread of blackberry (Rubus fruticosus agg.) and other weeds, and at least one has gone extinct over the last ten years.
Detailed taxonomy
Family
Synonyms
Nephrolepis var. pseudolauterbachii Hovenkamp et Miyam. appears to be a new name for the same species in the Polynesian part of its range; Nephrolepis auriculata (L.) Trimen
Taxonomic notes
Hovenkamp & Miyamoto (2005) treat Nephrolepis flexuosa as a synonym of N. cordifolia var. cordifolia. For N. cordifolia they indicate that the presence or absence of tubers has no taxonomic importance. They then recognise a distinct non-tuberous variety N. cordifolia var. pseudolauterbachii from the mid Pacific islands. However plants of var. pseudolauterbachii from Fiji had already been referred to N. flexuosa by de Lange et al. (2005), treated in that paper as distinct from N. cordifolia s.s. because of its lack of tubers, larger spores and distinctive tetraploid chromosome number (2n = 164). Thus the relegation of N. flexuosa by Hovenkamp & Miyamoto (2005) into synonymy with diploid N. cordifolia, yet apparent recognition of it (N. flexuosa) as the tetraploid var. pseudolauterbachii is inconsistent. At this stage NZPCN see no reason not to retain N. flexuosa as a valid indigenous New Zealand species.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
Spore bearing fronds may be found throughout the year
Fruiting
Spore bearing fronds may be found throughout the year
Propagation technique
Easy from division of whole plants, and also from fresh spores, which take about 6-8 months to fertilise and produce young plants.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs in uplands (non-wetlands).
Other information
Cultivation
Very rarely available from some specialist native plant nurseries.
Plant of the Month
This plant has been featured as a Plant of the Month – see Trilepidea: NZPCN newsletter for July 2007 for the full story.
Etymology
nephrolepis: Kidney scale
flexuosa: Flexuous
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
NEPFLE
Chromosome number
2n = 164
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | At Risk – Naturally Uncommon | Qualifiers: RR, SO
2012 | At Risk – Declining | Qualifiers: RR, SO
2009 | At Risk – Declining | Qualifiers: RR, SO
2004 | Range Restricted
Referencing and citations
References and further reading
Brownsey PJ, Smith-Dodsworth JC. 2000. New Zealand Ferns and Allied Plants. David Bateman, Auckland, NZ. 168 p.
de Lange PJ, Gardner RO, Sykes WR, Crowcroft GM, Cameron EK, Stalker F, Christian ML, Braggins JE. 2005. Vascular flora of Norfolk Island: some additions and taxonomic notes. New Zealand Journal of Botany 43(2): 563–596. https://doi.org/10.1080/0028825X.2005.9512975.
Hovenkamp PH, Miyamoto F. 2005. A conspectus of the native and naturalized species of Nephrolepis (Nephrolepidaceae) in the world. Blumea 50: 279–322. https://doi.org/10.3767/000651905X623003.
Attribution
Fact Sheet by P.J. de Lange 7 December 2005. Description based on Brownsey and Dodsworth (2000) supplemented with observations made from herbarium specimens.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Nephrolepis flexuosa Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/nephrolepis-flexuosa/ (Date website was queried)