{{Short description|Species of tree endemic to New Zealand}} {{distinguish|text = Oxandra lanceolata, which is also called '''lancewood'''}} {{Use New Zealand English|date=November 2024}} {{Speciesbox | image = Lancewood (Pseudopanax crassifolius).jpg | image_caption = A group of lancewood (''P. crassifolius'') trees in a forest in the Māhia Peninsula. | status = NT | status_system = NZTCS | status_ref = <ref name="constat">{{cite book |last1=de Lange |first1=P. J |last2=Rolfe |first2=J. R |last3=Barkla |first3=J. W |last4=Courtney |first4=S |last5=Champion |first5=P. D |last6=Perrie |first6=L. R |last7=Beadel |first7=S. M |last8=Ford |first8=K |last9=Breitwieser |first9=I |last10=Schönberger |first10=I |last11=Hindmarsh-Walls |first11=R |oclc=1041649797|title=Conservation status of New Zealand indigenous vascular plants, 2017 |date=2018 |publisher=Department of Conservation |location=Wellington, New Zealand }}</ref> | genus = Pseudopanax | species = crassifolius | authority = (Sol. ex A.Cunn.) C.Koch }}
'''''Pseudopanax crassifolius''''', also known as '''horoeka''' or '''lancewood''', is a heteroblastic tree belonging to the family Araliaceae. It is endemic to New Zealand and found throughout the country from sea level up to about {{convert|750|m|abbr=off}} in lowland to montane shrublands and forests.<ref name=allan/><ref name=nzpcn/>
The juvenile form, which lasts between 15 and 20 years, is easily recognised. The leaves are stiff and leathery with a prominent central rib, about 1 cm wide and up to 1 m long with irregular teeth, all growing downwards from a central stem. The young trunk has characteristic vertical swollen ridges. As the tree gets older the stem begins to branch, producing a bushy top. The leaves also become wider and shorter, losing their teeth. It is only when the tree is mature that it adopts a typical tree shape.
The difference between the juvenile and adult tree's appearance is so drastic that the two forms were initially described as separate species and even genera by early botanists,<ref name=NZnativetrees/><ref name=webb/> including the botanists accompanying Captain James Cook during his first voyage to New Zealand.<ref>{{cite book |last1=Dawson |first1=J. |last2=Lucas |first2=R. |title=Lifestyles of New Zealand forest plants |date=1993 |publisher=Victoria University Press |location=Wellington, New Zealand |isbn=978-0-86473-205-7}}</ref>
One of the theories about this curious change of appearance is that the young plant had to protect itself against browsing by the moa, a group of giant flightless birds that once roamed New Zealand's bush. Once above moa height, it was out of danger and turns into a "regular" tree. A study of leaf colour development in ''P. crassifolius'' found that leaves of seedlings would blend with leaf litter, while juvenile leaf colouration would draw attention to their spines. A closely related Chatham Island species, which evolved in the absence of moa, did not display these changes.<ref name="moa">{{cite journal|last=Fadzly|first=N.|author2=Jack, C. |author3=Schaefer, H.M. |author4= Burns, K.C. |title=Ontogenetic colour changes in an insular tree species: signalling to extinct browsing birds?|journal=New Phytologist|date=October 2009|volume=184|issue=2|pages=495–501|doi=10.1111/j.1469-8137.2009.02926.x|pmid=19674327|doi-access=free|bibcode=2009NewPh.184..495F }}</ref>
Closely related is ''Pseudopanax ferox'', the toothed lancewood. It is similar to ''P. crassifolius'' except the leaves are more abundant and severely toothed, resembling remotely a bandsaw blade.
==Description== thumb|225px| Juvenile ''Pseudopanax crassifolius'' tree thumb|225px| Adult ''Pseudopanax crassifolius'' tree
''Pseudopanax crassifolius'' is a heteroblastic plant, meaning that it has different leaf forms and growth habits depending on its growth stage.<ref name="doclance">{{cite web |title=Lancewood/horoeka |url=https://www.doc.govt.nz/nature/native-plants/lancewood-horoeka/ |website=www.doc.govt.nz |publisher=Department of Conservation |access-date=13 September 2024 |language=en-nz}}</ref><ref name=heteroblasty/> These growth stages, which are largely related to the plant height, are: seedling, juvenile, transitional, and adult.<ref name=heteroblasty>{{cite journal |last1=Gould |first1=K. |title=Leaf Heteroblasty in ''Pseudopanax crassifolius'': Functional Significance of Leaf Morphology and Anatomy |journal=Annals of Botany |date=January 1993 |volume=71 |issue=1 |pages=61–70 |doi=10.1006/anbo.1993.1007|bibcode=1993AnBot..71...61G }}</ref>
A juvenile tree is single-stemmed with long and narrow deflexed leaves,<ref name=allan/><ref name="germ"/> typically below the height of {{cvt|3–5|m}}.<ref name=moa/><ref name=heteroblasty/>
As an adult, ''P. crassifolius'' can reach a height of 15 m.<ref name=allan/> It appears as a round-headed tree due to being multi-branched,<ref name=allan/> making it look more like a "typical tree" than its previous forms.
=== Leaves ===
Seedling leaves are smaller and thinner compared to the following growth stages, but they gradually become longer as the plant grows out from the leaf litter, starting from cotyledon.<ref name=heteroblasty/> Leaves are initially green but become more mottled brown and leathery as the plant grows.<ref name=heteroblasty/>
Juvenile leaves, which are produced up to {{cvt|4|m}} or before the tree branches,<ref name=heteroblasty/> are especially long and narrow ({{cvt|1|m}} long by {{cvt|1–1.5|cm}} wide)<ref name=eagles/> – similar in shape to a lance.<ref name=webb/> They are dark green with a sharply toothed margin and prominent yellow or orange midrib.<ref name=heteroblasty/><ref name=knowyour/> Leaves are also rigid and straight, but angled downwards from the stem,<ref name="allan">{{cite book |last1=Allan |first1=H. H |title=Flora of New Zealand |date=1980|orig-date=1961 |publisher=R.E. Owen, Government Printer |location=Wellington, New Zealand |isbn=0-477-01041-5|oclc=977216383 }}</ref> 45–60º from horizontal.<ref name=orientation>{{cite journal |last1=Clearwater |first1=M. J. |last2=Gould |first2=K. S. |title=Leaf orientation and light interception by juvenile ''Pseudopanax crassifolius'' (Cunn.) C. Koch in a partially shaded forest environment |journal=Oecologia |date=1995 |volume=104 |issue=3 |pages=363–371|doi=10.1007/BF00328372 |pmid=28307593 |bibcode=1995Oecol.104..363C }}</ref>
Intermediate leaves appear once the tree has branched, typically above the height of 4–5 m.<ref name=heteroblasty/> They are an intermediate between juvenile and adult leaves, being shorter and wider than juvenile leaves.<ref name=heteroblasty/>
Adult leaves are shorter and wider ({{cvt|10–20|cm}} long by {{cvt|2–3|cm}} wide), with a less prominent midrib and toothed or entire margin.<ref name=heteroblasty/><ref name=eagles/> Additionally, leaves are simple, alternate,<ref name=fieldguide>{{cite book |last1=Dawson |first1=J. |title=Field guide to New Zealand's native trees |date=2020 |publisher=Potton & Burton |location=Nelson, New Zealand |isbn=978-1-988550-14-5 |edition=Revised}}</ref> and grow outwards or upwards from the branch.<ref>{{cite book |last1=Salmon |first1=J. T. |title=New Zealand flowers and plants in colour |date=1970 |publisher=Reed |location=Wellington, New Zealand |isbn=978-0-589-01095-9 |edition=2nd |oclc=768247525 }}</ref> They typically appear once the tree is above 5 m and branched.<ref name=heteroblasty/> Adult leaves also have greater frost resistance than juvenile leaves.<ref>{{cite journal |last1=Darrow |first1=H. E. |last2=Bannister |first2=P. |last3=Burritt |first3=D. J. |last4=Jameson |first4=P. E. |title=The frost resistance of juvenile and adult forms of some heteroblastic New Zealand plants |journal=New Zealand Journal of Botany |date=2001 |volume=39 |issue=2 |pages=355–363 |doi=10.1080/0028825X.2001.9512741 |bibcode=2001NZJB...39..355D |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825x.2001.9512741}}</ref>
=== Trunk ===
The trunk of a juvenile tree is slender,<ref name=knowyour>{{cite book |last1=Metcalf |first1=L. J. |title=Know your New Zealand trees |date=2006 |publisher=New Holland Publ |location=Auckland, New Zealand |isbn=978-1-86966-098-7}}</ref> straight,<ref name=webb>{{cite book |last1=Webb |first1=C. J. |last2=Johnson |first2=P. N. |last3=Sykes |first3=W. R. |title=Flowering plants of New Zealand |date=1990 |publisher=DSIR Botany |location=Christchurch, New Zealand |isbn=978-0-477-02584-3}}</ref> unbranched,<ref name=poole>{{cite book |last1=Poole |first1=A. L |last2=Adams |first2=N. M |editor1-last=West |editor1-first=C. J |title=Trees and shrubs of New Zealand |date=1994 |publisher=Manaaki Whenua Press |location=Christchurch, New Zealand |isbn=978-0-478-04535-2 |edition= Rev |oclc=33473843 }}</ref> and ridged down its length.
For adult trees, the trunk can be up to {{cvt|50|cm}} in diameter.<ref name=NZnativetrees>{{cite book |last1=Dawson |first1=J. |last2=Lucas |first2=R. |title=New Zealand's native trees |date=2019 |publisher=Potton & Burton |location=Nelson, New Zealand |isbn=978-0-947503-98-7}}</ref> It has horizontal lenticels<ref name=fieldguide/> and smooth, grey,<ref name=knowyour/> or mottled bark.<ref name=natureguide>{{cite book |last1=Dawson |first1=J. |last2=Lucas |first2=R. |title=Nature guide to the New Zealand forest |date=2000 |publisher=Godwit |location=Auckland, New Zealand |isbn=978-1-86962-055-4}}</ref> At this life stage, the top of the tree has branched and the juvenile leaves have fallen off, producing a rounded head with a naked stem.<ref name=knowyour/>
=== Flowers ===
The tiny, {{cvt|4|mm}} diameter, pale yellow to green<ref name=eagles>{{cite book |last1=Eagle |first1=A. L. |title=Eagle's complete trees and shrubs of New Zealand |date=2006 |publisher=Te Papa Press |location=Wellington, New Zealand |isbn=978-0-909010-08-9}}</ref> flowers are clustered in large terminal umbels, {{cvt|30|cm}} across.<ref>{{cite book |last1=Salmon |first1=J. T. |title=New Zealand flowers and plants in colour: 630 beautiful colour plates in native flora |date=1970 |publisher=Reed |location=Wellington, New Zealand |isbn=978-0-589-01095-9 |edition=2nd}}</ref> The flowers are bisexual, so they have five stamens and five styles.<ref name=NZnativetrees/>
=== Fruits ===
The fleshy fruits, which are usually dark purple to black when ripe, are {{cvt|3–4|mm}} in diameter and round. They contain five seeds per berry,<ref name=berries>{{cite journal |last1=Burrows |first1=C. J. |title=Fruit types and seed dispersal modes of woody plants in Ahuriri Summit Bush, Port Hills, western Banks Peninsula, Canterbury, New Zealand |journal=New Zealand Journal of Botany |date=1994 |volume=32 |issue=2 |pages=169–181 |doi=10.1080/0028825X.1994.10410366 |bibcode=1994NZJB...32..169B |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825X.1994.10410366|url-access=subscription }}</ref> with the five locules each containing one seed.<ref name="germ"/>
== Taxonomy ==
The species was first described by Daniel Solander in his unpublished manuscripts detailing the First voyage of James Cook in 1779. Solander The juvenile and adult forms of the plant were so visually different that Solander used two different names for the plant: ''Aralis crassifolia'' for the adult form, and ''Xerophylla longifolia'' for the juvenile form.<ref name="MaraReo">{{cite web|url=https://www.temarareo.org/PPN-Soroeka.html |title=*Solo[w]eka ~ *Folo[w]eka |website=Te Mära Reo |publisher=Benton Family Trust |access-date=14 August 2025}}</ref><ref name="MeaningTrees">{{cite q|Q118646408|pp=230-233}}</ref> The first formal description of the plant was made in 1839 by Allan Cunningham, who retained the name ''Aralis crassifolia''.<ref>{{cite Q|Q56100177}}</ref> In 1859, Karl Koch placed the species in the genus ''Pseudopanax'',<ref>{{cite journal|url=https://books.google.com/books?id=5KgCAAAAYAAJ&pg=PA366 |title=Die Araliaceen |journal=Wochenschrift für Gärtnerei und Pflanzenkunde |language=German |place=Berlin |last1=Koch |first1=Karl |author-link1=Karl Koch (botanist) |last2=Fintelmann |first2=G. A. |date=17 November 1859 |volume=2 |number=46 |page=366}}</ref> which remains the modern scientific name used today.<ref name=nzpcn/>
== Etymology ==
The species epithet crassifolius means "thick leaved".<ref name="MeaningTrees"/> The Māori language name horoeka likely derived from Proto-Polynesian *Solo[w]eka or *Qoromea, both hypothetical words used to refer to unknown species of tree. Possible cognates include Tahitian oroea, used to describe ''Cyclophyllum barbatum'', Rennellese kogomea, a word for ''Hibiscus cooperi'', and Hawaiian olomea, used to describe ''Perrottetia sandwicensis''.<ref name="MaraReo"/> All three lancewood species (''P. crassifolius'', ''P. ferox'', and ''P. linearis'') are known as horoeka by Māori.<ref name=doclance/>
The English language name lancewood refers to the Māori cultural use of the juvenile plant as a lance for bird hunting. An alternative early name no longer in use is the "fishbone tree", a reference of the juvenile plant's leaves resembling the spine and ribs of a fish.<ref name="MeaningTrees"/>
== Range ==
''Pseudopanax crassifolius'' is endemic to New Zealand.<ref name=nzpcn>{{cite web |title=''Pseudopanax crassifolius'' |url=https://www.nzpcn.org.nz/flora/species/pseudopanax-crassifolius/ |website=New Zealand Plant Conservation Network |language=en}}</ref> It is abundant and widespread in the North Island, South Island, and Stewart Island.<ref name=allan/>
==Habitat==
''Pseudopanax crassifolius'' occurs from sea level up to about {{cvt|750|m}} in lowland to montane forests and shrublands.<ref name=allan/> It does not have a strong affinity for wet habitats, as it usually occurs in uplands/non-wetlands.<ref>{{cite web |last1=Clarkson |first1=B. R. |title=A vegetation tool for wetland delineation in New Zealand |url=https://www.landcareresearch.co.nz/assets/Discover-Our-Research/Biodiversity/Species-ecosystem-services/Restoring-wetland-ecosystem-functioning/vegetation_tool_wetland_delineation.pdf |website=Manaaki Whenua – Landcare Research |doi=10.7931/J2TD9V77 |date=2013}}</ref> Instead, this species is often growing along forest margins or gaps, in regenerating forests, and as a subcanopy or canopy tree.<ref name=germ/>
Specifically, ''P. crassifolius'' is a common subcanopy or canopy species in a kāmahi — silver fern forest (Beech-broadleaved-podocarp forest Alliances),<ref>{{cite web |title=''Weinmannia racemosa'' - ''Cyathea dealbata'' - ''Knightia excelsa'' (''Beilschmiedia tawa'') / ''Leucopogon fasciculatus'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/beech-broadleaved-podocarp-forest-alliances/kamahi-silver-fern-forest/ |website=Manaaki Whenua – Landcare Research |access-date=20 September 2024}}</ref> hard beech – kāmahi forest (Beech forest Alliances),<ref>{{cite web |title=''Nothofagus truncata'' – ''Weinmannia racemosa'' (''N. menziesii'')/ ''Leucopogon fasciculatus'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/beech-forest-alliances/hard-beech-kamahi-forest/ |website=Manaaki Whenua – Landcare Research |access-date=20 September 2024}}</ref> silver beech-red beech-kāmahi forest (Beech-broadleaved forest Alliances),<ref>{{cite web |title=''Nothofagus menziesii'' - ''Weinmannia racemosa'' - ''N. fusca'' / ''Blechnum discolor'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/beech-broadleaved-forest-alliances/silver-beech-red-beech-kamahi-forest/ |website=Manaaki Whenua - Landcare Research |access-date=20 September 2024}}</ref> Silver fern - mahoe forest,<ref>{{cite web |title=''Cyathea dealbata'' - ''Melicytus ramiflorus'' - ''Freycinetia baueriana'' - ''Ripogonum scandens'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/broadleaved-podocarp-forest-alliances-including-kauri/silver-fern-mahoe-forest/ |website=Manaaki Whenua - Landcare Research |access-date=20 September 2024}}</ref> tōwai – tawa forest,<ref>{{cite web |title=''Weinmannia silvicola'' – ''Beilschmiedia tawa'' / ''Freycinetia banksii'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/broadleaved-podocarp-forest-alliances-including-kauri/towai-tawa-forest/ |website=Manaaki Whenua - Landcare Research |access-date=20 September 2024}}</ref> and kāmahi-podocarp forest (Broadleaved-podocarp forest Alliances including kauri).<ref>{{cite web |title=''Weinmannia racemosa'' – ''Prumnopitys ferruginea'' - ''Dacrydium cupressinum'' / ''Blechnum discolor'' forest |url=https://www.landcareresearch.co.nz/publications/woody-ecosystem-types/broadleaved-podocarp-forest-alliances-including-kauri/kamahi-podocarp-forest/ |website=Manaaki Whenua - Landcare Research |access-date=20 September 2024}}</ref>
==Ecology== ===Phenology and reproduction=== thumb|Fruits of ''Pseudopanax crassifolius''
The juvenile form of ''P. crassifolius'' lasts between 15 and 20 years before it transitions into its adult form.<ref name="doclance"/><ref name=knowyour/>
The tree almost only flowers and fruits when it is an adult.<ref name=heteroblasty/> Its bisexual flowers are in full bloom from January to April<ref name=bee/> and are pollinated by insects.<ref name=gender>{{cite journal |last1=Webb |first1=C. J. |last2=Lloyd |first2=D. G. |last3=Delph |first3=L. F. |title=Gender dimorphism in indigenous New Zealand seed plants |journal=New Zealand Journal of Botany |date=1999 |volume=37 |issue=1 |pages=119–130 |doi=10.1080/0028825X.1999.9512618 |bibcode=1999NZJB...37..119W |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825X.1999.9512618}}</ref> Fruits are produced in January to April, ripen through the winter, and persist until August.<ref name="germ"/> These fruits are eaten and then dispersed by birds.<ref name="germ"/> Passing through a bird's gut strips the seed of its fleshy mesocarp coat, which helps it germinate.<ref name="physiology">{{cite book |last1=Bannister |first1=P. |last2=Jameson |first2=P. E. |editor1-last=Coolbear |editor1-first=P. |editor2-last=Cornford |editor2-first=C. A. |editor3-last=Pollock |editor3-first=K. M. |title=Seed Development and Germination |date=1994 |publisher=Agronomy Society of New Zealand. |location=Christchurch, New Zealand |pages=9–15 |url=https://www.agronomysociety.org.nz/uploads/94803/files/SP9_5._NZ_native_plants_germination_physiology.pdf}}</ref> Subsequently, these seeds were found to germinate after five weeks<ref name="germ"/> but this may be delayed if the fleshy mesocarp is still intact.<ref name="physiology"/><ref>{{cite journal |last1=Bannister |first1=P. |last2=Bridgman |first2=J. |title=Responses of seeds of three species of ''Pseudopanax'' to low temperature stratification, removal of fruit flesh, and application of gibberellic acid |journal=New Zealand Journal of Botany |date=1991 |volume=29 |issue=2 |pages=213–216 |doi=10.1080/0028825X.1991.10416723 |bibcode=1991NZJB...29..213B |issn=0028-825X}}</ref>
''Pseudopanax crassifolius'' is evergreen.<ref name=germ/>
===Predators, parasites, and diseases=== ====Birds==== thumb|Kererū feeding on ''Pseudopanax crassifolius'' fruit
The berries serve as an important food source for many birds.<ref name="doclance"/> This includes birds like the hihi,<ref>{{cite journal |last1=Perrott |first1=J. K. |last2=Armstrong |first2=D. P. |title=Vegetation composition and phenology of Mokoia Island, and implications for the reintroduced hihi population |journal=New Zealand Journal of Ecology |date=2000 |volume=24 |issue=1 |pages=19–30 |url=https://www.researchgate.net/publication/228489089}}</ref> North Island kōkako,<ref name=kokako>{{cite journal |last1=Leathwick |first1=J. R. |last2=Hay |first2=J. R. |last3=Fitzgerald |first3=A. E. |title=THE INFLUENCE OF BROWSING BY INTRODUCED MAMMALS ON THE DECLINE OF NORTH ISLAND KOKAKO |journal=New Zealand Journal of Ecology |date=1983 |volume=6 |pages=55–70|url=https://newzealandecology.org/system/files/articles/NZJEcol6_55.pdf }}</ref> whitehead, tūī,<ref name="doclance"/> kererū, silvereye, New Zealand bellbird,<ref name="germ">{{cite journal |last1=Burrows |first1=C. J. |title=Germination behaviour of the seeds of seven New Zealand woody plant species |journal=New Zealand Journal of Botany |date=1996 |volume=34 |issue=3 |pages=355–367 |doi=10.1080/0028825X.1996.10410700 |bibcode=1996NZJB...34..355B |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825X.1996.10410700}}</ref><ref name=berries/> New Zealand kākā, brown creeper, grey warbler, tomtit, blackbird, and chaffinch.<ref name=birdforage>{{cite journal |last1=O'Donnell |first1=C. F. J. |last2=Dilks |first2=P. J. |title=Foods and foraging of forest birds in temperate rain-forest, South Westland, New Zealand |journal=New Zealand Journal of Ecology |date=1994 |volume=18 |issue=2 |pages=87–107 |url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=8e41dadfbab4d9e3f3bb4d711ad75f13b1397db7}}</ref>
Its flowers also provide nectar, which honey-eating birds like the hihi,<ref>{{cite journal |last1=CASTRO |first1=I. |last2=ROBERTSON |first2=A. W. |title=HONEYEATERS AND THE NEW ZEALAND FOREST FLORA: THE UTILISATION AND PROFITABILITY OF SMALL FLOWERS |journal=New Zealand Journal of Ecology |date=1997 |volume=21 |issue=2 |pages=169–179 |url=https://newzealandecology.org/nzje/2025.pdf |issn=0110-6465 |oclc=9987025958}}</ref> tūī, and New Zealand bellbird use for food.<ref name=birdforage/>
As well as the fruit, kererū will also eat the leaf buds of ''P. crassifolius''.<ref name=birdforage/>
Birds are also known to forage for invertebrates on ''P. crassifolius''. This includes the kākā, rifleman, brown creeper, grey warbler, tomtit, New Zealand fantail, silvereye, and New Zealand bellbird.<ref name=birdforage/>
Although extinct, it is also believed that the moa may have once predated this plant, specifically its leaves.<ref name=moa/>
====Invertebrates==== Bees introduced and native to New Zealand, like the western honey bee<ref name=bee>{{cite journal |last1=Butz Huryn |first1=V. M. |title=Use of native New Zealand plants by honey bees ( ''Apis mellifera'' L.): A review |journal=New Zealand Journal of Botany |date=1995 |volume=33 |issue=4 |pages=497–512 |doi=10.1080/0028825X.1995.10410621|bibcode=1995NZJB...33..497B }}</ref> or ''Lasioglossum sordidum'',<ref>{{cite book |last1=Donovan |first1=B. J. |title=Fauna of New Zealand 57 |date=2007 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |pages=1–295 |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ57Apoidea.pdf |chapter=Apoidea (Insecta: Hymenoptera).}}</ref> will use this species for nectar when it is flowering. As a result, beekeepers believe ''P. crassifolius'' to be good bee forage and recommend it on farms.<ref name=bees>{{cite book |last1=Newstrom-Lloyd |first1=L. E. |title=Pollination in New Zealand |date=2013 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |url=https://www.landcareresearch.co.nz/assets/Publications/Ecosystem-services-in-New-Zealand/2_11_Newstrom.pdf}}</ref>
thumb|left|''Eumetriochroa panacivagans'' leaf mine on juvenile ''Pseudopanax crassifolius'' leaf
Moth species Acrocercops panacivagans and ''Eumetriochroa panacivagansis'' are known to use ''Pseudopanax'' species like ''P. crassifolias'' as hosts.<ref name=acrocercops/><ref name=leafminer>{{cite journal |last1=Hoare |first1=R. J. B. |last2=Patrick |first2=B. H. |last3=Buckley |first3=T. R. |title=A new leaf-mining moth from New Zealand, ''Sabulopteryx botanica'' sp. nov., with a revised checklist of New Zealand Gracillariidae |journal=ZooKeys |date=2019 |issue=865 |pages=39–65 |doi=10.3897/zookeys.865.34265|doi-access=free |pmid=31379443 |pmc=6663935 }}</ref> This is evident through the mines they create in the leaves.<ref name=acrocercops>{{cite journal |last1=Watt |first1=M. N. |title=The leaf mining insects of New Zealand |journal=Transactions and Proceedings of the New Zealand Institute |date=1920 |volume=52 |pages=439–466}}</ref><ref name=leafminer/> Another moth species, ''Izatha blepharidota'', will also take this plant as a host, with its larvae successfully reared and feeding on the dead branches of ''P. crassifolius''.<ref>{{cite book |last1=Hoare |first1=R. J. B |last2=Rhode |first2=B. E. |title=Izatha: (Insecta: Lepidoptera: Gelechioidea: Oecophoridae) |date=2010 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |isbn=978-0-478-34724-1}}</ref>
The New Zealand praying mantis will deposit its ootheca on ''P. crassifolius''.<ref>{{cite journal |last1=Bowie |first1=M. K. |last2=Bowie |first2=M. H. |title=Where does the New Zealand praying mantis, ''Orthodera novaezealandiae'' (Colenso) (Mantodea: Mantidae), deposit its oothecae? |journal=New Zealand Entomologist |date=2003 |volume=26 |issue=1 |pages=3–5 |doi=10.1080/00779962.2003.9722103 |bibcode=2003NZEnt..26....3B |url=https://researcharchive.lincoln.ac.nz/server/api/core/bitstreams/c0826b0f-19ba-4eab-a6f4-ded82985dd91/content|url-access=subscription }}</ref>
Many beetle species are known to parasitise ''P. crassifolius'', commonly by using it as a host. Weevil species from the family Curculionidae and Belidae have larvae that live in dead, or dying, woody parts of ''P. crassifolius'', including ''Dendrotrupes vestitus'', ''Ectopsis ferrugalis'', ''Platypus apicalis'', ''Scolopterus penicillatus'', ''Stephanorhynchus curvipes'',<ref name=hutcheson>{{cite journal |last1=Hutcheson |first1=J. |title=Notes of the ecology of ''Ectopsis ferrugalis'' (Curculionidae) |journal=New Zealand Entomologist |date=1991 |volume=14 |issue=1 |pages=41–44 |doi=10.1080/00779962.1991.9722612|bibcode=1991NZEnt..14...41H }}</ref> ''Psepholax simplex'', ''Psepholax mediocris'', ''Psepholax crassicornis'', ''Mesoreda sulcifrons'', ''Crisius semifuscus'', ''Clypeolus pascoei'',<ref>{{cite book |last1=Lyal |first1=C. H. C. |title=Fauna of New Zealand 29 |date=1993 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |pages=1–307 |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ29Lyal1993_001.pdf |chapter=Cryptorhynchinae (Insecta: Coleoptera: Curculionidae)}}</ref> ''Phronira osculans'',<ref>{{cite journal |last1=May |first1=B. M. |title=Immature stages of Curculionoidea (Coleoptera): Rearing records 1964-1986 |journal=New Zealand Entomologist |date=1987 |volume=9 |issue=1 |pages=44–56|doi=10.1080/00779962.1987.9722492 |bibcode=1987NZEnt...9...44M }}</ref> ''Dendrotrupes costiceps''<ref>{{cite book |last1=May |first1=B. M. |title=Fauna of New Zealand 28 |date=1993 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |pages=1–223 |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ28May1993_001.pdf |chapter=Larvae of Curculionoidea (Insecta: Coleoptera): a systematic overview}}</ref> and ''Aralius wollastoni''.<ref>{{cite book |last1=Kuschel |first1=G. |title=Fauna of New Zealand 45 |date=2003 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ45Belidae.pdf |chapter=Nemonychidae, Belidae, Brentidae (Insecta: Coleoptera: Curculionoidea)}}</ref> Two longhorn beetle species, ''Tetrorea cilipes'' and ''Hexatricha pulverulenta'' from the family Cerambycidae, have larvae that tunnel in the woody parts of trees and are believed to use ''P. crassifolius'' as a host.<ref name=hutcheson/><ref>{{cite book |last1=Hosking |first1=G. P. |title=Forest and Timber Insects of New Zealand 28 |date=1978 |publisher=Forest Research Institute, New Zealand Forest Service |location=Rotorua, New Zealand |chapter=''Hexatricha pulverulenta'' (Westwood) (Coleoptera: Cerambycidae) squeaking longhorn}}</ref>
Scale insects will use ''P. crassifolius'' as a host plant by living on its leaves, petioles, fruit, and stems. Notably, ''Trioza panacis'', also known as the lancewood psyllid, will feed on the leaves of ''P. crassifolius'' and a few other ''Pseudopanax'' species.<ref>{{cite web |last1=Martin |first1=N. A. |title=Lancewood psyllid - ''Trioza panacis'' |url=https://interestinginsects.landcareresearch.co.nz/taxa/e930b88e-390a-4295-a71d-aa2556722ed2 |website=Interesting insects and other invertebrates |publisher=Manaaki Whenua – Landcare Research |access-date=15 September 2024}}</ref> Additional scale insect species include those from the family Diaspididae, such as ''Leucaspis gigas'', ''Leucaspis mixta'', ''Leucaspis morrisi'',<ref>{{cite journal |last1=de Boer |first1=J. A. |last2=Valentine |first2=E. W. |title=The identity of ''Leucaspis gigas'' (Homoptera: Diaspididae), with descriptions of four similar species in New Zealand |journal=New Zealand Journal of Zoology |date=1977 |volume=4 |issue=2 |pages=153–164 |doi=10.1080/03014223.1977.9517947}}</ref> and ''Hemiberlesia lataniae''.<ref>{{cite book |last1=Henderson |first1=R. C. |title=Fauna of New Zealand 66 |date=2011 |publisher=Manaaki Whenua press |location=Lincoln, New Zealand |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ66Diaspididae144.pdf |chapter=Diaspididae (Insecta: Hemiptera: Coccoidea)}}</ref> From the family Coccidae, this includes the soft-scale insect species ''Ctenochiton viridis'' and ''Coccus hesperidum''.<ref>{{cite book |last1=Hodgson |first1=C. J. |last2=Henderson |first2=R. C. |title=Fauna of New Zealand 41 |date=2000 |publisher=Manaaki Whenua press |location=Lincoln, New Zealand |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ51MaleCoccidae.pdf |chapter=Coccidae (Insecta: Hemiptera: Coccoidea)}}</ref> Felted scale insects from the family Eriococcidae, like ''Scutare fimbriata'' and ''Eriococcus parabilis''.<ref>{{cite book |last1=Hoy |first1=J. M. |title=Eriococcidae (Homoptera: Coccoidea) of New Zealand |date=1962 |publisher=New Zealand Department of Scientific and Industrial Research |location=Wellington, New Zealand}}</ref> Finally, from the family Rhyparochromidae, ''Woodwardiana evagorata'' will feed on the leaves of ''P. crassifolius''.<ref>{{cite book |last1=Larivière |first1=M. -C. |last2=Larochelle |first2=A. |title=Fauna of New Zealand 50 |date=2004 |publisher=Manaaki Whenua Press |location=Lincoln, New Zealand |pages=1–330 |url=https://www.landcareresearch.co.nz/assets/Publications/Fauna-of-NZ-Series/FNZ50Heteroptera.pdf |chapter=Heteroptera (Insecta: Hemiptera): catalogue}}</ref>
thumb|Adult leaves of ''Pseudopanax crassifolius''
====Mammals==== ''Pseudopanax crassifolius'' leaves are palatable and preferred by mammals introduced to New Zealand, such as cattle,<ref name="cattle">{{cite journal |last1=Timmins |first1=S. M. |title=Impact of cattle on conservation land licensed for grazing in South Westland, New Zealand |journal=New Zealand Journal of Ecology |date=2002 |volume=26 |issue=2 |pages=107–120 |url=https://www.nzes.org.nz/nzje/free_issues/NZJEcol26_2_107.pdf}}</ref> deer, brushtailed possums, and feral goats.<ref name=kokako/><ref>{{cite web |last1=MacLeod |first1=C. J. |last2=Affeld |first2=K |last3=Allen |first3=R. B. |last4=Bellingham |first4=P. J. |last5=Forsyth |first5=D. M. |last6=Gormley |first6=A. M. |last7=Holdaway |first7=R. J. |last8=Richardson |first8=S. J. |last9=Wiser |first9=S. K. |title=Department of Conservation biodiversity indicators: 2012 assessment |url=https://www.landcareresearch.co.nz/assets/researchpubs/department_of_conservation_biodiversity_indicators_2012_assessment.pdf |website=Manaaki Whenua – Landcare Research |access-date=13 September 2024}}</ref><ref name=possum>{{cite journal |last1=Pekelharing |first1=C. J. |last2=Frampton |first2=C. M. |last3=Suisted |first3=P. A. |title=Seasonal variation in the impacts of brushtailed possums (''Trichosurus vulpecula'') on five palatable plant species in New Zealand beech (''Nothofagus'') forest |journal=New Zealand Journal of Ecology |date=1998 |volume=22 |issue=2 |pages=141–148 |url=https://researcharchive.lincoln.ac.nz/server/api/core/bitstreams/25e6a0cf-e91b-482c-9651-8c030fa600ee/content |issn=0110-6465 |oclc=9986937558}}</ref> The leaves of a mature ''P. crassifolius'' tree are known to have a higher nutritive value compared to its juvenile form, which may make them more appealing to these mammals.<ref>{{cite journal |last1=Mitchell |first1=N. D. |title=A STUDY OF THE NUTRITIVE VALUE OF JUVENILE AND ADULT LEAVES OF ''PSEUDOPANAX CRASSIFOLIUS'' |journal=New Zealand Journal of Ecology |date=1980 |volume=3 |page=159 |issn=0110-6465 |oclc=9986861407}}</ref> Alongside leaves, the berries of ''P. crassifolius'' are eaten by brushtail possums.<ref>{{cite journal |last1=Burrows |first1=C. J. |title=Seed trapping in Ahuriri Summit Bush Scenic Reserve, Port Hills, western Banks Peninsula, 1985–1986 |journal=New Zealand Journal of Botany |date=1994 |volume=32 |issue=2 |pages=183–215 |doi=10.1080/0028825X.1994.10410367 |bibcode=1994NZJB...32..183B |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825X.1994.10410367}}</ref> Rats will also predate ''P. crassifolius'', as they are known to eat its seeds.<ref>{{cite book |last1=Campbell |first1=D. J. |title=Changes in numbers of woody plant seedlings on Kapiti Island after rat eradication |date=2002 |publisher=Department of Conservation |location=Wellington, New Zealand |isbn=978-0-478-22238-8 |url=https://www.doc.govt.nz/globalassets/documents/science-and-technical/SfC193.pdf}}</ref>
====Plants==== The parasitic plant ''Dactylanthus taylorii'' has been reported to grow on the roots of ''P. crassifolius'', where it steals nutrients by causing the roots to enlarge.<ref>{{cite journal |last1=ECROYD |first1=C. E. |title=THE ECOLOGY OF ''DACTYLANTHUS TAYLORII'' AND THREATS TO ITS SURVIVAL |journal=New Zealand Journal of Ecology |date=1996 |volume=20 |issue=1 |pages=81–100 |url=https://newzealandecology.org/nzje/1991.pdf}}</ref>
thumb|One example of ''Pseudopanax crassifolius'' × ''lessonii'' hybrid leaf morphology
====Fungi==== ''Chaenothecopsis schefflerae'', a fungus that lives on plant exudate or exudate-soaked wood or bark, has been found on ''P. crassifolius''.<ref>{{cite journal |last1=Beimforde |first1=C. |last2=Tuovila |first2=H. |last3=Schmidt |first3=A. R. |last4=Lee |first4=W. G. |last5=Gube |first5=M. |last6=Rikkinen |first6=J. |title=''Chaenothecopsis schefflerae'' (Ascomycota: Mycocaliciales): a widespread fungus on semi-hardened exudates of endemic New Zealand Araliaceae |journal=New Zealand Journal of Botany |date=2017 |volume=55 |issue=4 |pages=387–406 |doi=10.1080/0028825X.2017.1360368 |bibcode=2017NZJB...55..387B |url=https://www.tandfonline.com/doi/pdf/10.1080/0028825X.2017.1360368|url-access=subscription |hdl=10138/309572 |hdl-access=free }}</ref>
===Hybrids===
''Pseudopanax crassifolius'' commonly hybridises with ''Pseudopanax lessonii.''<ref name="phylo">{{cite journal |last1=Perrie |first1=L. R. |last2=Shepherd |first2=L. D. |title=Reconstructing the species phylogeny of ''Pseudopanax'' (Araliaceae), a genus of hybridising trees |journal=Molecular Phylogenetics and Evolution |date=September 2009 |volume=52 |issue=3 |pages=774–783 |doi=10.1016/j.ympev.2009.05.030 |pmid=19500681 |bibcode=2009MolPE..52..774P }}</ref> Given the two species' dissimilar appearances, they produce a range of morphologically diverse offspring, with leaves often appearing different to both parent species.<ref name="phylo"/> Despite this, ''Pseudopanax crassifolius'' hybridises with ''P. lessonnii'' significantly more frequently than with morphologically similar ''Pseudopanax'' species, such as ''Pseudopanax ferox'' or ''Pseudopanax linearis''.<ref name="phylo"/> One theory relating to this process is that ''P. crassifolius'' is more closely related to ''P. lessonnii'' and its allies than other ''Pseudopanax'' species.<ref name="phylo"/>
==Evolution== The heteroblastic nature of this species has resulted in up to seven theories as to why it has evolved such distinct seedling, juvenile, and adult forms.<ref name=doclance/>
thumb|left|Brown ''Pseudopanax crassifolius'' seedling
One theory is that the heteroblasty of ''P. crassifolius'' evolved as a defensive adaptation to prevent and deter moa predation.<ref name=moa/><ref>{{cite journal |last1=Greenwood |first1=R. M. |last2=Atkinson |first2=I. A. E. |title=Evolution of divaricating plants in New Zealand in relation to moa browsing |journal=Proceedings of the New Zealand Ecological Society |date=1977 |volume=24 |pages=21–33 |issn=0077-9946}}</ref> The brown, mottled ''P. crassifolius'' seedling camouflages against leaf litter, which may have made it harder for moa to detect.<ref name=moa/> Once the tree grows too tall to blend in with the leaf litter, researchers believe that the long, rigid juvenile leaves with teeth along the margin might deter moa browsing because they would be difficult to swallow.<ref name=moa/> A highlighted coloured patch often seen along the teeth of the leaf may have warned moa to its defenses.<ref name="moa"/> The prominent midrib of the juvenile leaf allows it to be 13 times stronger than adult leaves, which would have made it more resistant to breakage by moa.<ref name=heteroblasty/> It is also believed that once ''P. crassifolius'' is above 3 m in height, it exceeds the maximum browsing for moa.<ref name=moa/> This may explain why we see the tree transition into its adult form, around this height, as it becomes less vulnerable to moa predation. Additionally, because moa were absent from the Chatham Islands, ''Pseudopanax chathamicus'', a close relative of ''P. crassifolius'' that is endemic to the Chatham Islands, lacks the same defensive adaptations.<ref name=chatham>{{cite journal |last1=Burns |first1=K. C. |last2=Dawson |first2=J. W. |title=Heteroblasty on Chatham Island: a comparison with New Zealand and New Caledonia |journal=New Zealand Journal of Ecology |date=2009 |volume=33 |issue=2 |pages=156–163 |issn=0110-6465 |oclc=9987297350}}</ref> Instead, the juvenile leaves of ''P. chathamicus'' are large and broad, with a smooth margin.<ref name="chatham"/> ''Pseudopanax chathamicus'' leaves also appear the same green colour throughout its development, lacking the colour changes seen in ''P. crassifolius''.<ref name="moa"/> Lastly, ''P. chathamicus'' begins branching as it transitions to an adult much earlier than ''P. crassifolius''.<ref name="chatham" /> These differences suggest that moa predation did influence the evolution of ''P. crassifolius''.
thumb|Juvenile ''Pseudopanax crassifolius'' leaf featuring distinctive colouring along its teeth
Another theory about the heteroblasty of ''P. crassifolius'' is that it evolved due to varying light intensities that the plant experiences as it grows from below to above the forest canopy.<ref name=lighttheory>{{cite journal |last1=DAY |first1=J. S. |title=LIGHT CONDITIONS AND THE EVOLUTION OF HETEROBLASTY (AND THE DIVARICATE FORM) IN NEW ZEALAND |journal=New Zealand Journal of Ecology |date=1998 |volume=22 |issue=1 |pages=43–54}}</ref> The seedling and juvenile leaves of ''P. crassifolius'' are thought to share morphological and anatomical traits with plants that commonly grow in low-light environments, while adult leaves share traits with plants that grow under the sun.<ref name=heteroblasty/> As a juvenile, ''P. crassifolius'' often occurs as a partially shaded subcanopy tree before it eventually grows above the canopy as an adult. The deflexed orientation of its juvenile leaves optimises capture of low-intensity light received in the subcanopy environment.<ref name=orientation/><ref name=lighttheory/> The subcanopy's low-light environment creates a low-energy, making the juvenile leaves low-cost to produce compared to the adult leaves.<ref name=lighttheory/> As ''P. crassifolius'' grows, it enters a high-light-intensity environment above the canopy, allowing it to produce large but expensive leaves as an adult.<ref name=lighttheory/> For these reasons, researchers believe that the juvenile form of ''P. crassifolius'' may be adapted for low-light intensity conditions, while the adult form is adapted to high-light intensity conditions.<ref name=lighttheory/> With that being said, one study found that species without heteroblasty (homoblastic species) had a greater survival rate than heteroblastic seedlings in a low-light intensity treatment, meaning that heteroblasty in ''P. crassifolius'' may not provide much advantage in a subcanopy environment.<ref>{{cite journal |last1=Gamage |first1=H. K. |title=Phenotypic variation in heteroblastic woody species does not contribute to shade survival |journal=AoB Plants |date=2011 |volume=2011 |article-number=plr013 |doi=10.1093/aobpla/plr013 |pmid=22476483 |pmc=3129537 }}</ref>
==Uses== ===Urban design===
thumb|180px|The trunk of an adult ''Pseudopanax crassifolius''
''Pseudopanax crassifolius'' is a popular plant in urban design not only for its iconic and charismatic appearance but also for its ecological benefits. Its unique look can be used to create textural contrast amongst other plants.<ref>{{cite web |last1=NZ Transport Agency |title=SH20 Manukau Extension urban and landscape design master plan |url=https://www.nzta.govt.nz/assets/resources/urban-design/sh-20-manukau-extension/docs/uldm-2.pdf |website=NZ Transport Agency Waka Kotahi |access-date=15 September 2024}}</ref> Because of its thin and tall juvenile form, this species is also great in small spaces.<ref>{{cite book |last1=Ignatieva |first1=M. |last2=Meurk |first2=C. D. |last3=Van Roon |first3=M. |last4=Simcock |first4=R. |last5=Stewart |first5=G. H. |title=How to put nature into our neighbourhoods: Application of Low Impact Urban Design and Development (LIUDD) principles, with a biodiversity focus, for New Zealand developers and homeowners. |date=2008 |publisher=Manaaki Whenua - Landcare Research New Zealand |location=Lincoln, New Zealand |isbn=978-0-478-09397-1 |url=https://researcharchive.lincoln.ac.nz/server/api/core/bitstreams/39b1dd2e-fd23-44a2-b13c-096d64b15bb8/content}}</ref> For these reasons, this species is recommended along streets, entrance ways, traffic islands, or in the central island of roundabouts.<ref name=LIUDD>{{cite journal |last1=Ignatieva |first1=M. |last2=Stewart |first2=G. |last3=Meurk |first3=C. D. |title=Low Impact Urban Design and Development (LIUDD): matching urban design and urban ecology |journal=Landscape Review |date=2008 |volume=12 |issue=2 |pages=61–73 |url=https://researcharchive.lincoln.ac.nz/server/api/core/bitstreams/74ab4ac8-2112-4cc7-aa9a-82c5d1164502/content}}</ref> It was once a choice wood for rod building
===Early European settler use=== The midribs of juvenile leaves were once used as bootlaces or in fixing horse bridles and harnesses.<ref name=doclance/> Its dense, light brown wood was used for fence posts or piles.<ref name=knowyour/> In fact, its wood was once used for timber in Otago.<ref name=doclance/> However, the wood is not known to be very durable.<ref name=doclance/> Additionally, the flexible trunk would sometimes be used as a whip.<ref name=doclance/>
===Traditional Māori use===
Māori would use the stems of juvenile trees to spear kererū, while Māori specifically from the South Island would use ''P. crassifolius'' leaves to make paint brushes for rock paintings.<ref name=doclance/> Due to its flexibility, the trunk of a young ''P. crassifolius'' could be twisted and used as a tokotoko (ceremonial walking stick).<ref>{{cite web |title=Native trees and their connections with people |url=https://www.doc.govt.nz/globalassets/documents/getting-involved/students-and-teachers/native-tree-factsheets/trees-with-people-connections-sheet.pdf |website=Department of Conservation |access-date=21 September 2024}}</ref>
==In Māori culture== Māori thought that a flowering ''P. crassifolius'' indicated that birds would be abundant the following year because they would be attracted to the ripened fruit.<ref name=doclance/>
==Conservation== ''Pseudopanax crassifolius'' is a non-threatened species, meaning it has large, stable populations.<ref name="constat"/> Mammalian browsing is a current threat to ''P. crassifolius''. For example, brushtailed possum browsing is known to cause defoliation and death to mature trees.<ref name="doclance"/> Cattle browsing also impacts the abundance of ''P. crassifolius'', with one study finding the plant only in areas devoid of cattle.<ref name="cattle"/>
==References== {{Reflist}}
==External links== *''Flora of New Zealand'', URL: [http://floraseries.landcareresearch.co.nz/pages/Taxon.aspx?id=_e781ffb2-4b03-4fff-9999-18a8ba0956ce&fileName=Flora%201.xml ''Pseudopanax crassifolius'']. *''New Zealand Plant Conservation Network'', [http://nzpcn.org.nz/flora_details.asp?ID=1196 ''Pseudopanax crassifolius''].
{{Commons-inline|Pseudopanax crassifolius}} {{Taxonbar|from=Q7255222}}
crassifolius Category:Endemic flora of New Zealand Category:Trees of New Zealand Category:Trees of mild maritime climate