T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Weinmannia racemosa (Kamahi)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Oxalidales
Family:  Cunoniaceae (semi tropical genus and includes similar trees to Weinmannia racemosa such as the Cunonia capensis (Butterknife tree)
Genus: Weinmannia
Binomial name: Weinmannia racemosa
Common names: Kamahi,

Weinmannia racemosa is a medium-sized tree of the family Cunoniaceae, is a very common tree in New Zealand, occurring in lowland, montane, and subalpine forests and shrubland from the central North Island south to Stewart Island. Weinmannia racemosa Is the dominant tree on Mt Egmont/Taranaki and that's unique as virtually all New Zealand mountains have beech trees as the dominate tree, Mt Egmont/Taranaki has none. The theory is the eruptions killed all the beech. In Taranaki. Except for local gardens the closest specimens growing wild are found  at Awakino or near Whangamomana.
Weinmannia racemosa sometimes begins life as an epiphyte on the trunks of tree ferns, kamahi attains its greatest height of 25 or more metres in the Catlins forests of the south-eastern South Island.
It has small creamy-white flowers in erect spikes. Kamahi generally occurs with other broadleaf trees, at times acting as a pioneer species which is eventually succeeded by the southern beeches (Nothofagus spp.
It is a  spreading tree to 25m with dark green leathery leaves.
It produces masses of creamy flowers in summer. It can be found in regenerating bush or is often common on clay banks on the side of the road and streams. The flowers are sweet scented and produced in profusion in November and December.
Kamahi bark is greyish, with white blotches and relatively smooth. Kamahi bark was a rich native source of tannins, which were used to dye cloaks and mats and to preserve fishing lines. Its timber, often protected by tapu, was durable and "lucky" for fishing rods. 
The Maori also use kamahi as a chest tonic if kumarahou is not available. It is given to people suffering from the flu, bronchitis, heavy chest colds; the bark being boiled and the infusion drunk. This was also used to bathe wounds, burns, etc since it has antiseptic qualities, as well as accelerating healing.
The tannic acid from the bark reacts with the ferrous salts in the paru - the mud in certain swamps, etc., - to produce a strong and permanent black dye.
With its high tannin content (10 – 13%) the bark was much used in early European times by tanners, who apparently almost wiped the species out in the Auckland region.

Large mature tree in flower, Mt Egmont reserve.


 



The flower colour is darker on some trees. Photographed late November, New Plymouth








A single flower.


Juvenile capsules with two pink partly fused styles.  They turn red then brown as they mature



Flower buds, an inflorescence and the seed heads.

The serrated leaf of the Weinmannia racemosa


Underneath surface of leaf


The adult leaves have a joint at the end of the stalk, and indication they are derived from a compounded juvenile.




Base of two leaf stalks


The multitrunks of a Weinmannia racemosa


A young juvenile shrub growing up a bank.