Machaerina complanata
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Sedges
Detailed description
Dark green, tufted and leafy sedge. Culms 05–0.9–(1.3) m tall, c. 3 mm wide, smooth, ± compressed. Leaves ± = culms, 4–8 mm wide, flat, distichous, isobilateral equitant, striated, pale green, tip acute, margins glabrous. Panicle 0.15–0.50 m long, narrow, erect from a long sheath with short lamina; branchlets flexible, fascicled from upper sheaths. Spikelets, c. 5 mm 1ong, light red-brown, 2–3-flowered, 1–2 flowers fertile. Glumes 5–6, ovate, acuminate or acute, chartaceous, striped with brown, scabrid on back towards tip, margins minutely ciliate. Nut, including beak, c. 4 × 2 mm, trigonous, red-brown, very shortly stipitate, narrowed above to a long, triquetrous, scabrid beak.
Similar taxa
Machaerina sinclairii is similar but has much wider (10–30–(40) mm) light green (rather than dark green) leaves, some what fluffy brown more pendulous rather than erect to suberect, non-fluffy inflorescences, and the persistant style base of M. sinclairii is about the same length as the nut, and though rather narrow is quite conspicuous. In Machaerina complanata the style-base though persistant , is usually turgid, much shorter than the nut and usually inconspicuous.
Distribution
Endemic. Known only from the North Island, where it now occurs locally from Te Paki south to the Kaipara Harbour. It was also once present in the Waikato on the shores of Lake Waaihi, and there are recent subfossil deposits made by this species in peat bogs (now drained) at Papamoa and Te Puke (Bay of Plenty).
Habitat
Coastal to lowland (1–300 m a.s.l.). A species of open habitats which has been collected from estuaries (in salt marsh), consolidated dune swales (which are seasonally wet), freshwater lake and river margins, amongst gum land scrub, under regenerating kauri, from the margins of geothermally active springs and fumaroles, and from acidic peat bogs.
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 | Threatened – Nationally Vulnerable | Qualifiers: DPT, PF, RF
Threats
At all known sites seedlings are scarce (or absent altogether). Many populations are senescent or flower infrequently, and few are on protected land. Indications are that this is a light-demanding plant which in the wild is succumbing to natural succession. In heavy shade plants will not flower. In the past this species was regarded as highly threatened, and at that time the key threat had been habitat loss caused by wetland drainage. Discoveries since the 1990s indicate that this species is not necessarily confined to wetlands, and potentially can grow in any suitably open habitat.
Detailed taxonomy
Genus
Family
Synonyms
Cladium complanatum Bergg., Baumea complanata (Bergg.) Blake
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–November
Fruiting
November–March (but fruits of varying ages may be found throughout the year)
Propagation technique
Difficult and should not be removed from the wild. Fresh seed germinates easily (usually within 1–3 months) but plants resent root disturbance and seedlings need to be handled with care as any root damage will kill them. Once seedlings establish it is easy to grow. Does well in wet or dry but prefers full sun. Experimentation with growing conditions at Oratia Native Plant Nurseries showed this species does best when planted in fresh, untreated pine saw dust. Seed set varies from year to year, and there is some indication that it has mast years. For example, 2005 was a particularly good seeding year, while the previous four years were not.
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]
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Other information
Plant of the Month
This plant has been featured as a Plant of the Month – see Trilepidea: NZPCN newsletter for June 2011 for the full story.
Etymology
complanata: Levelled or flattened
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.
MACCOM
Chromosome number
2n = c.50
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 | Threatened – Nationally Vulnerable | Qualifiers: RF
2012 | Threatened – Nationally Vulnerable | Qualifiers: RF
2009 | Threatened – Nationally Vulnerable | Qualifiers: RF
2004 | Range Restricted
Regional conservation statuses
Auckland: 2025 | Regionally Threatened – Regionally Endangered | Qualifiers: Sp, DPR, DPS, DPT, PF, RR
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
Referencing and citations
References and further reading
McCluggage AP. 2000. New location of Baumea complanata at Shenstone Te Paki Northern New Zealand. Auckland Botanical Society Journal 55: 68–69.
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (8 September 2004). Description adapted from Moore & Edgar (1970).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.