Acaena novae-zelandiae
Common names
red bidibid
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified description
An evergreen shiny or dull bright green herb, which spreads up to 1.5 metres across and about 15cm in height. Found all over New Zealand in varied habitats. The pinnate leaves are sharply toothed and have hairs on the tips. The globe shaped flower balls are white, then grow into a cluster of red hooked spikes, which when ripe brown off, become firm and may stick to your socks or laces when brushed past in order to disperse.
Flower colours
White
Detailed description
Stoloniferous, prostrate, trailing perennial herb, forming a loose mat up to 1.5 metres in diameter. Stems 1.5-2 mm diameter, hairy, up to 1 metre long, and/or 15 cm high, rooting at nodes; Stipules entire to pentafid; Leaves odd-pinnate, rachis often red, between 20-110 mm long with 9-15 leaflets; Leaflets oblong to elliptical 4-17 × 2-10 mm, serrated toothed margin, 8-15 teeth hair-tipped, terminal leaflet 9-12 mm long, lower leaflets are smaller, upper surface shiny (especially new growth) slightly channelled glabrous bright green to dull green (depending on age) veins obvious, lower surface pale green hairy along veins; Inflorescence scape 100-150 mm, finely hairy; Capitulum about 9 mm diameter when flowering, composed of 80-120 florets, each floret has 4 sepals, 2 (rarely 3) stamen, white anthers, 1 style, 1 achene; Fruit roughly cone-shaped, each having 4 red barb-tipped spines, up to 7.5-12 mm long, which mature dry, pale brown or golden brown when ripe, enabling attachment to passing hairy/feathered surfaces as vector, and/or to aid wind dispersal, tiny spines occasionally occur in between foremost spines.
Similar taxa
Acaena pallida is similar but only found in coastal gravels and dunes. It too and can be shiny especially new growth, it also has red spikes on unripe fruit. It differs by generally having larger leaflets 6-30 × 3-13 mm (compared to 4-17 × 2-10 mm) and has very hairy stems. The leaflets are not hair-tipped as is seen in A. novae-zelandiae. A. pallida is not as common due to its habitat requirements.
Distribution
Indigenous. North Island, South Island, Stewart Island, Chatham Islands, Campbell Island, Also found in South East Australia, and New Guinea.
Habitat
Lowland to alpine (0-1700m.a.s.l.), from forest edge to open grassland scrubland and coastal environments.
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 | Not Threatened | Qualifiers: SO
Detailed taxonomy
Genus
Family
Taxonomic notes
A. novae-zelandiae is naturalised on Campbell Island, where it readily hybridises with A. minor var. antarctica; it is also naturalised in Britain, Ireland and California.
This species is renowned to hybridise with other New Zealand species, in Dawson (1960), it is suggested this species is often one of the parents and produces vigorous unusual specimens which may make it difficult for the observer to define.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
October-February.
Fruiting
November-June.
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
Etymology
acaena: From the Greek ‘akanthos’ thorn, referring to the spiny calyx that many species have
novae-zelandiae: Of New Zealand
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.
ACANOV
Chromosome number
2n = 42
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 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Auckland: 2025 | Regionally Not Threatened | Qualifiers: DPS, DPT, TL
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.
Otago: 2025 | Regionally Not Threatened
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Conservation Status of Indigenous Vascular Plants in Otago, 2025” Jarvie S et al. (2025) report.
Referencing and citations
References and further reading
Allan HH. 1961. Flora of New Zealand. Volume 1. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. Government Printer, Wellington, NZ. pg. 360-361.
Dawson JW. 1960. Natural Acaena hybrids in the vicinity of Wellington. In Transactions of the Royal Society of New Zealand Volume 88: pp. 13-27.
Lloyd K. 2001. A Key and notes for Acaena (Rosaceae) in New Zealand. Botanical Society of Otago Newsletter 25. Pgs.10-14.
Webb CJ, Sykes WR, Garnock-Jones PJ. 1988. Flora of New Zealand, Volume IV. Naturalised Pteridophytes, Gymnosperms, Dicotyledons. Botany Division, Department of Scientific and Industrial Research, Christchurch, NZ. Pg. 1062.
Attribution
Fact sheet prepared for NZPCN by MD Ward (August 29th 2025). Description adapted from Lloyd (2001), Webb et. al. (1988), Allan (1961).
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.