Coriaria arborea var. arborea
Poisonous plant
Common name
tutu, tree tutu
Family
Coriariaceae
Flora category
Vascular – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Trees & Shrubs - Dicotyledons
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.
CORAVA
Chromosome number
2n = 40
Current conservation status
The threat classification status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – a suggested threat classification status has not been assessed by the NZTCS panel.
Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Not Threatened
Previous conservation statuses
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Brief description
Common robust much-branched large shrub inhabiting disturbed areas. Twigs square in cross-section, bearing pairs of 50-80mm long glossy green elliptical leaves that do not have a leaf stalk. Flowers in drooping spikes up to 30cm long. Fruit black.
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).
UPL: Obligate Upland
Rarely is a hydrophyte, almost always in uplands (non-wetlands).
Flower colours
Green
Life cycle
Fleshy berries are dispersed by frugivory (Thorsen et al., 2009).
Etymology
coriaria: From the Latin corium ‘hide’, possibly from the use of some species for tanning leather
arborea: From the Latin arbor ‘tree’, meaning tree-like
Poisonous plant
Tutu is the classic poisonous plant of NZ. It is a widely distributed native species found throughout New Zealand, particularly along stream banks and in regenerating native bush. Some of the first animals introduced to NZ by Captain Cook in the 18th Century were poisoned by it. The plant caused losses in cattle and sheep. All parts of all Coriaria species are poisonous except the succulent black, soft fleshy petals surrounding the seeds (the seeds themselves are also poisonous). Poisoning is usually through eating the seeds, berries or poisonous honey.
Tutin acts on the central nervous system leading to symptoms of nausea, vomiting, burred vision, weakness and seizures or convulsions and can lead to a comatose state. Breathing is usually affected, so too is memory.
Toxic honey is contaminated as a result of bees visiting tutu (Coriaria arborea) with honey dew being excreted onto the leaves of the plant by the tiny toxic sap sucking passion vine hopper (Scolypopa australis) and then bees gathering the honeydew.
Tutin, and its derivative, hyenanchin are extremely toxic to humans, but only a few areas in NZ regularly produce toxic honey. These include the Coromandel Peninsula and Eastern Bay of Plenty and the Marlborough Sounds.
A number of people have been killed, incapacitated and hospitalised over the years from eating toxic honey. The last recorded case from commercial honey was in 1974 involving 13 patients. There have been 9 cases since 1974 with the last known poisonings occurring in 1991 in the Eastern Bay of Plenty area and 2008 in the Coromandel.
See also the 2008 news item about toxic honey causing illness in the Coromandel.
Click on this link for more information about Poisonous native plants.
References and further reading
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309