Pseudopanax crassifolius

Not to be confused with Oxandra lanceolata, which is also called lancewood.

Pseudopanax crassifolius
Adult tree

Not Threatened (NZ TCS)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Apiales
Family: Araliaceae
Genus: Pseudopanax
Species:
P. crassifolius
Binomial name
Pseudopanax crassifolius
(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 750 m in lowland to montane shrublands and forests.[2][3]

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,[4][5] including the botanists accompanying Captain James Cook during his first voyage to New Zealand.[6]

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.[7]

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.

  1. ^ de Lange, P. J; Rolfe, J. R; Barkla, J. W; Courtney, S; Champion, P. D; Perrie, L. R; Beadel, S. M; Ford, K; Breitwieser, I; Schönberger, I; Hindmarsh-Walls, R (2018). Conservation status of New Zealand indigenous vascular plants, 2017. Wellington, New Zealand: Department of Conservation. OCLC 1041649797.
  2. ^ Cite error: The named reference allan was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference nzpcn was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference NZnativetrees was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference webb was invoked but never defined (see the help page).
  6. ^ Dawson, J.; Lucas, R. (1993). Lifestyles of New Zealand forest plants. Wellington, New Zealand: Victoria University Press. ISBN 9780864732057.
  7. ^ Fadzly, N.; Jack, C.; Schaefer, H.M.; Burns, K.C. (October 2009). "Ontogenetic colour changes in an insular tree species: signalling to extinct browsing birds?". New Phytologist. 184 (2): 495–501. doi:10.1111/j.1469-8137.2009.02926.x. PMID 19674327.