urtica ferox

U. ferox can grow to a height of 3 m (9.8 ft) with the base of the stem reaching 12 cm (4.7 in) in thickness. The pale green leaves are very thin like a membrane and the surface of the leaf, stems and stalks are covered in stiff stinging hairs that can grow up to {{convert|6|mm|in|abbr=on}} long. These spines are prominent along the salient mid-vein and leaf margin. The leaves range from {{convert|3-5|cm|in|abbr=on}} in width and {{convert|8-12|cm|in|abbr=on}} in length, these are oppositely arranged and there are two stipules per node. The leaf shape is ovulate-triangulate with a serrated leaf margin each bearing a spine of up to {{convert|1|m|abbr=on}}. The spines covering the leaf surface, stem and stalk are generally no larger than {{convert|6|mm|abbr=on}} in length, the spines on the older darker bark are smaller and softer - these don't cause a sting. This nettle is winter deciduous in cold climates, evergreen in mild climates and can lose its leaves in drought conditions if it is growing in shallow soils.{{Cite web|title=Urtica ferox|url=https://www.nzpcn.org.nz/flora/species/urtica-ferox/|access-date=2021-04-20|website=New Zealand Plant Conservation Network |language=en}}{{Cite journal|last=Burrows|first=C. J.|date=1996-06-01|title=Germination behaviour of seeds of the New Zealand woody species Melicope simplex, Myoporum laetum, Myrsine divaricata, and Urtica ferox|url=https://doi.org/10.1080/0028825X.1996.10410685|journal=New Zealand Journal of Botany|volume=34|issue=2|pages=205–213|doi=10.1080/0028825X.1996.10410685|bibcode=1996NZJB...34..205B |issn=0028-825X}}

Flowering occurs from November to March and because U. ferox is a dioecious shrub it will cross pollinate,Eagle, A. (1986)." Eagle’s tree and shrubs of New Zealand: volume one revised". Auckland, New Zealand: Williams Collins (NEW ZEALAND) LtdWardle, J. (2011). "Wardle’s Native Trees of New Zealand and their story". Wellington, New Zealand: New Zealand Farm Forestry Association with transferral between the flowers enabled by the wind. Pollen grains are collected by the densely packed stigmas on the flowers and seed dispersal is carried out by rolling, wind, and by birds.Webb, C.J., Johnson, P.R., Sykes, W.R., (1990). "Flowering Plants of New Zealand". Christchurch, New Zealand: Botany Division, D.S.I.R The fruit, which are achenes, mature in January, each containing one 1.5 mm long, brown coloured, ovoid-shaped seedSalmon, J.T. (1998). "Native Trees of New Zealand 2". Auckland, New Zealand: Reed Books which takes one month to germinate. In his study on the germination behaviour of 5 different vascular seeding species, C. J. Burrows found that U. ferox had the lowest germination rate of 59% compared to >85% for the other similar species. He surmised that it is capable of building up a large seed bank in the soil which may survive for several years, citing that European species in the genus Urtica produce seed banks.

File:Urtica ferox needles.jpg|Needles along the leaf mid-vein

File:Urtica ferox early flowering.jpg|Buds and flowers developing

File:Urtica ferox habit.jpg| Growth habit

The toxin present in the spines contain the neurotransmitters histamine, serotonin and acetylcholine. A 2022 study in the Journal of Biological Chemistry found that two peptides: Δ-Uf1a and β/δ-Uf2a, are likely responsible for the painful sensations. Δ-Uf1a is suggested to create pain by disturbing cell membranes and β/δ-Uf2a the same by modulating voltage-gated sodium channels. Stings have a painful reaction which causes hives, numbness, and itchiness. In severe cases it can also cause: ataxia, blurred vision, confusion, polyneuropathy, respiratory distress, and hypersalivation. The reaction can potentially be fatal.{{Cite journal |last1=Xie |first1=Jing |last2=Robinson |first2=Samuel D. |last3=Gilding |first3=Edward K. |last4=Jami |first4=Sina |last5=Deuis |first5=Jennifer R. |last6=Rehm |first6=Fabian B.H. |last7=Yap |first7=Kuok |last8=Ragnarsson |first8=Lotten |last9=Chan |first9=Lai Yue |last10=Hamilton |first10=Brett R. |last11=Harvey |first11=Peta J. |last12=Craik |first12=David J. |last13=Vetter |first13=Irina |last14=Durek |first14=Thomas |date=2022 |title=Neurotoxic and cytotoxic peptides underlie the painful stings of the tree nettle Urtica ferox |journal=Journal of Biological Chemistry |volume=298 |issue=8 |pages=1 |doi=10.1016/j.jbc.2022.102218 |doi-access=free |issn=0021-9258 |pmc=9352542 |pmid=35780839}}{{Cite journal |last1=Hammond-Tooke |first1=Graeme D. |last2=Taylor |first2=Peter |last3=Punchihewa |first3=Saman |last4=Beasley |first4=Michael |date=2007 |title=Urtica ferox neuropathy |url=https://onlinelibrary.wiley.com/doi/10.1002/mus.20730 |journal=Muscle & Nerve |language=en |volume=35 |issue=6 |pages=804–807 |doi=10.1002/mus.20730 |pmid=17206658 |s2cid=28044856 |issn=0148-639X|url-access=subscription }}{{Cite journal |last1=Kanzaki |first1=Mami |last2=Tsuchihara |first2=Toyokazu |last3=McMorran |first3=Denise |last4=Taylor |first4=Peter |last5=Hammond-Tooke |first5=Graeme D. |date=2010 |title=A rat model of Urtica ferox neuropathy |url=https://linkinghub.elsevier.com/retrieve/pii/S0161813X10001348 |journal=NeuroToxicology |language=en |volume=31 |issue=6 |pages=709–714 |doi=10.1016/j.neuro.2010.07.004|pmid=20650289 |bibcode=2010NeuTx..31..709K |url-access=subscription }}

There has been one recorded human death from contact—a lightly clad hunter who died five hours after walking through a dense patch.[http://www.teara.govt.nz/TheBush/NativePlantsAndFungi/PoisonousPlantsAndFungi/1/en Poisonous native plants], Te Ara: The Encyclopedia of New Zealand There is also one other likely death, with the mystery of the death only being solved by the pathologist years afterwards.{{Cite web |date=2024-01-20 |title=Cold-case twist: How a casual chat helped solve mystery of body in the bush |url=https://www.nzherald.co.nz/nz/jason-chase-death-pathologist-solves-cause-of-death-after-chance-encounter/AK475AZTW7J4ZALO7GHQJ3IN74/ |access-date=2024-01-20 |website=The New Zealand Herald |language=en-NZ}}

U. ferox is endemic to New Zealand and inhabits coastal and lowland forests and shrublands in the North, South, and Stewart Islands.{{Cite book|last=Eagle|first=Audrey Lily|url=https://www.worldcat.org/oclc/85262201|title=Eagle's complete trees and shrubs of New Zealand|publisher=Te Papa Press|others=Audrey Lily Eagle, Audrey Lily Eagle|year=2006|isbn=978-0-909010-08-9|location=Wellington, N.Z.|pages=416|oclc=85262201}} It is commonly found in clearings or forest margins, often forming large patches, from 0–600 m above sea level. It has also been recorded on the Hen and Chicken Islands along stream-beds.{{Cite Q|Q58676572}}

File:Red Admiral caterpillar 01.JPG

Although U. ferox is a toxic shrub, it also plays a significant part in the phenology of a native butterfly, namely the red admiral (Vanessa gonerilla). The leaves of the tree nettle is the preferred food and provide protection for the butterfly larvae. When the larvae arrives in the leaves, it will curve the tip of nettle leaf, use the silken threads to make the leaves stick together, and construct a secure place where it can eat the food.Barron, M.C., Wratten, S.D. & Barlow, N.D.(2004) "Phenology and parasitism of the red admiral butterfly Brassaris gonerilla (Lepidoptera: Nymphalidae)." New Zealand Journal of Ecology, 28/(1), 105-111Landcare research.(2005). "Red Admiral." Retrieved from [http://www.landcareresearch.co.nz/resources/identification/animals/bug-id/alphabetic-list-of-bugs/red-admiral. http://www.landcareresearch.co.nz/resources/identification/animals/bug-id/alphabetic-list-of-bugs/red-admiral]. Due to the caterpillar's activities, the leaves of shrub can fall off. The eggs of butterflies, also including the yellow admiral (Vanessa itea), are laid on the leaves of nettle during the spring and summer. It takes eight to ten days for the eggs to incubate. Beside these butterflies, some mammalian pests also eat the leaves of tree nettle, like the Common brushtail possum,Cowan, P.E. (1990) "Fruits, seeds, and flowers in the diet of brushtail possums, Trichosurus vulpecula, in lowland podocarp/mixed hardwood forest, Orongorongo Valley," New Zealand. New Zealand Journal of Zoology,17,549–566 goats and deer.Brockie, R. (1992)."A living New Zealand forest." Auckland, New Zealand: David Batemann Ltd However, because no non-flying, non-marine mammals existed in New Zealand prior to human arrival in the last one thousand years, it is unadapted for them.

U. ferox requires high nutrient levels found in cycling forest systems such as those found in native New Zealand forest. In these environments an “A type” soil horizon of rich leaf litter and humus between 10 – 80 cm is common. This is significant as the species doesn't directly compete with other flora, this is achieved through inhabiting the boundary zones between strata, therefore the high soil fertility. Like other species in the nettle family it grows well in soils with high nutrient levels; especially in high quantities of nitrogen.Rollwagen, A.(2006). Species Profile: Tree Nettle. Retrieved from Canterbury Nature: http://www.canterburynature.org/species/lincoln_essays/treenettle.php Access to open sunlight and rainwater results in a rapidly growing plant able to take advantage of natural tree fall and other natural events such as land slides and flooding which clear dominating old growth species.

In Māori folklore, Kupe was said to have placed several obstacles, including {{lang|mi|ongaonga}}, to hinder pursuers whose wives he had stolen.

Tree nettle has been eaten, and used medicinally.{{medical citation needed|date=May 2016}} Māori used the bark of tree nettle and the leaves of kawakawa, boiled together, to make a liquid that can be used internally and externally for eczema and venereal disease.{{cite web|title=Urtica ferox. Ongaonga. Tree nettle.|url=http://maoriplantuse.landcareresearch.co.nz/WebForms/PeoplePlantsDetails.aspx?firstcome=firstcome&PKey=7BC13C99-341D-4369-A421-DBEDD13DBA7D|website=Landcare Research Manaaki Whenua|publisher=Landcare Research New Zealand|access-date=17 January 2016}} Also, the leaves of tree nettle play a significant part in the treating of pains. The decoction of leaves and young twigs dipped in boiled water is said to have been used for stomach ache and as treatment for gonorrhea.Adames, O.(1945). "Maori medical plants." Auckland, New Zealand: Auckland Botanical Society Bulletin.Wardle, J. (2011). "Wardle’s Native Trees of New Zealand and their story. "Wellington, New Zealand: New Zealand Farm Forestry Association{{MEDRS|date=May 2016}} Urtica ferox was also a food source for Māori. The inner stems were sometimes consumed after the leaves and outer bark had been removed,DoC.(2006, March).Retrieved from Department of Conservation: http://www.doc.govt.nz/documents/getting-involved/students-and-teachers/field-trips-by-region/kapiti-education-kit/Species%20cards/ongaonga-tree-nettle.pdf the thin film that makes up the inner bark was also eaten raw and is said to have a sweet taste, it is also documented that stems were cooked after having the leaves removed.Best, E. (1903). "Food products of Tuhoeland: being notes on the food-supplies of a non-agricultural tribe of the natives of New Zealand; together with some account of various customs, superstitions etc. pertaining to foods." Wellington, New Zealand: Transactions of the New Zealand Institute.

• List of poisonous plants

{{Reflist}}

• {{cite book

| last = Connor

| first = H. E.

| title = Poisonous Plants in New Zealand (DSIR Research Bulletin 99)

| orig-year = 1952

| edition = 2nd

| year = 1977

| publisher = Government Printer

| location = Wellington

| id = {{Listed Invalid ISBN|0-477-01007}}

}}

• {{cite book

| last = Crowe

| first = Andrew

| date = 1999-09-07

| title = Which Native Forest Plant?

| publisher = Penguin

| location = New Zealand

| isbn = 0-14-028631-4

}}

• {{cite book

| last = Hutching

| first = Gerard

| year = 1998

| title =Natural World of New Zealand | publisher = Viking (Penguin)

| location = New Zealand

| isbn = 0-670-87782-4

}}

{{Commons category|Urtica ferox}}

• Urtica ferox discussed on RNZ Critter of the Week, [https://www.rnz.co.nz/audio/player?audio_id=2018887920 28 April 2023]

{{Taxonbar|from=Q2024246}}

Category:Trees of New Zealand

ferox

Category:Endemic flora of New Zealand

Category:Dioecious plants