Peraxilla colensoi
Past favourite plant finalist
Common names
Scarlet mistletoe, korukoru, pirita, roeroe
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Trees & Shrubs - Dicotyledons
Simplified description
Fleshy shrub to 3m wide growing on outer branches of beech trees with glossy green fleshy paired leaves and masses of red tubular flowers. Leaves to 8cm long, smooth with a red edge. Flowers to 2.5cm long. Fallen petals litter forest floor under plants. Fruit yellow.
Flower colours
Red/Pink
Detailed description
A shrub up to 3 m across. It parasitises further out on branches of its host than Peraxilla tetrapetala. The veins on leaves are hardly evident and only the midrib is conspicuous. Leaf tips are never notched and the leaves themselves are large and never blistered. The leaves sit in pairs on opposite sides of the stem and are thick and have a leathery texture. Leaf margins are usually smooth with red slightly rough margins. Masses of scarlet flowers make this plant very obvious from October - January. Flower heads have groups of 3-10 flowers and are up to 60 mm long. The ripe fruit are yellow/golden and are small, fleshy and oval.
Similar taxa
Peraxilla tetrapetala, Ileostylus micranthus. Peraxilla colensoi is a larger plant with larger leaves than P. tetrapetala, has flowers in clumps of 3-10 and grows on silver beech. P. tetrapetala has leaves with blister galls, flowers in clumps of 1-3 and grows on black or mountain beech. Ileostylus micranthus does not grow on beech trees and has small, greenish flowers.
Distribution
North and South Island, but common only in southern parts of the South Island.
Habitat
A parasite mainly found in silver beech forest but has been recorded on 16 host species (9 exotic) in New Zealand including red beech and black beech. Tui (Prosthemadera novaeseelandiae) and bellbird (Anthonis melanura) disperse this species in the North Island.
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 – Declining | Qualifiers: CD
Threats
A wide variety of threats are now acknowledged as working in unison to cause the national decline of this and allied leafy mistletoes species. The most obvious threat seems to be brush tailed possums (Trichosurus vulpecula), which heavily browse mistletoes, to such an extent that they are held as the primary cause for the loss of the beech mistletoes from large parts of the countries beech forest.
Detailed taxonomy
Genus
Family
Synonyms
Elytranthe colensoi (Hook.f.) Engl. Loranthus colensoi Hook. f.
Endemic taxon
Yes
Endemic genus
Yes
Endemic family
No
Ecology
Flowering
October to January
Propagation technique
Can be grown from fresh seed placed on suitable host tissue (ideally Nothofagus menziesii). Although seed germinates readily the ability of the seedling to form a firm host is rather variable. Failure rates are high and experimentation with plenty of fresh seed is usually needed.
Other information
Ecological notes
Image of the haustoria of Peraxilla colensoi by John Dawson (from Forest Vines to Snow Tussocks).
Etymology
colensoi: Named after William Colenso (7 November 1811 - 10 February 1899) who was a Cornish Christian missionary to New Zealand, and also a printer, botanist, explorer and politician.
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.
PERCOL
Chromosome number
2n= 24
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 – Declining | Qualifiers: CD
2012 | At Risk – Declining | Qualifiers: CD
2009 | At Risk – Declining | Qualifiers: CD
2004 | Gradual Decline
Regional conservation statuses
Otago: 2025 | Regionally At Risk – Regionally Declining | Qualifiers: CD, DPS, DPT, NR, PD, SP
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
Attribution
Fact sheet prepared by P.J. de Lange for NZPCN (1 June 2013)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Peraxilla colensoi Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/peraxilla-colensoi/ (Date website was queried)