Species

Sophora chathamica

Etymology

Sophora: after the Arabic name for a similar tree
chathamica: From the Chatham Islands

Common Name(s)

Kowhai, coastal kowhai

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Sophora chathamica Cockayne

Family

Fabaceae

Brief Description

A kowhai tree bearing leaves to 150mm long that have leaflets 6-16mm long by 4-8mm wide that slightly overlap and get smaller towards the tip and with bunches of drooping yellow flowers and dry ridged and knobbly seed pods 50-180mm long containing hard yellow seeds. Juvenile and adults similar.

Flora Category

Vascular - Native

NVS Species Code

SOPCHA

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.

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

Sophora microphylla var. chathamica (Cockayne) Yakolev, Sophora microphylla subsp. microphylla var. chathamica (Cockayne) Yakolev

Distribution

Endemic. A primarily coastal species known from North, South and Chatham Islands but probably only indigenous to the northern half of the North Island, where it is common in the west from the Tongaporutu River to Te Paki. In the east it is abundant south to about Thames, so far it has not been reported south and east of there. Very common around Auckland, the Hauraki Gulf and from Port Waikato south to Kawhia. There are some inland occurrences in the lower Waikato Basin. Disjunct occurrences around Wellington, the Chatham Islands and Whanganui Inlet may result from deliberate plantings by the Maori.

Habitat

Primarily a species of coastal forest, often on cliff faces or banks overlooking estuarine rivers or inlets. Occasionally found in swamp forest.

Features

Tree up to 20 m tall, with one or more trunks. Branches spreading to upright. Juveniles weakly flexuose. Leaves on seedlings and juveniles moderately to densely leafy, 4.4-9 x 4.4-7.5 mm, orbicular to very broadly obovate, crowded, usually overlapping. Adult leaves up to 150 mm long, imparipinnate, usually pubescent, hairs, straight, appressed. Leaflets 25-55, crowded and overlapping, 6-16 x 4-8 mm, broadly elliptic, broadly obovate, broadly ovate, obovate to orbicular, distal leaflets usually smaller than proximal. Inflorescences racemose with up to 11 flowers. Calyx 8-10 x 10-13 mm, cupulate. Flowers yellow, keel petal blade 29-43 x 9-11 mm, wing petal blade 25-42 x 9-11 mm, standard petal blade 25-34 x 20-25 mm; petals with distinct claws 4-6 mm long. Fruit 50-180 mm long, 4-winged, brown, with up to 12 seeds. Seeds 5.5-8 x 4.-5. mm, oblong, elliptic to orbicular, yellow to light yellow-brown.

Similar Taxa

Distinguished from all other Kowhai species by the absence of a divaricating/filiramulate juvenile stage; with leaflets 6-16 x 4-8 mm; and by the distal leaflets usually smaller than proximal, crowded and overlapping (especially toward distal end), with leaflets broadly elliptic, broadly obovate, broadly ovate, obovate to more or less orbicular, with all parts moderately hairy.

Flowering

August-November

Flower Colours

Yellow

Fruiting

October-September

Propagation Technique

Easy from seed, provided the hard seed shell is nicked first with a knife or rubbed with sandpaper to expose the endosperm. Soaking seed treated this way overnight often helps speed up germination. Can be grown with difficulty from cuttings.

Threats

The main threat that faces all wild New Zealand kowhai species is the risk posed through planting for revegetation and horticultural purposes of hybrid material, foreign species, such as the Chilean Pelu (S. cassioides) and also of kowhai species outside their natural range. However, S. chathamica seems to be very common throughout its range, and is adequately protected within a range of reserves and land set aside for conservation purposes. The nativity of the Chatham Island populations is not clear, and though assumed to be planted by Maori, because this assertion needs further study and the trees are culturally significant they require direct management. Few (if any Chatham Island) plants can be said to exist in truly secure habitats.

Chromosome No.

2n = 18

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Where To Buy

Commonly available at most commercial nurseries. A popular native tree for larger gardens. Very commonly sold in garden centres, where it is often sold as either S. microphylla or S. tetraptera. Some plants with a superficial resemblance to S. chathamica and offered by nurseries usually as S. microphylla or S. tetraptera have, upon closer inspection, turned out to be the closely related Chilean pelu (S. cassioides).

Poisonous plant

All parts of the plant but especially the ripe yellow seed are poisonous. Because the seed are hard they will take a lot of chewing to cause harm, and also will need to be consumed in large quantities to effectively poison a human. If the seed are crushed before eating it is more likely that they will cause harm. The major toxin is Cytisine and symptoms of poisoning include nausea, vomiting, increased heart rate, twitching of muscles or loss of coordination. Onset of these symptoms may occur within one hour. In extreme cases symptoms include paralysis and respiratory failure. Click on this link for more information about Poisonous native plants.

Attribution

Fact Sheet prepared for NZPCN by P.J. de Lange (31 July 2004). Description adapted from Heenan et al. (2001).

References and further reading

Anonymous. 1944. Kowhai. Wellington Botanical Society Bulletin, 9: 4-5

Heenan, P.B.; de Lange, P. J.; Wilton, A. D. 2001: Sophora (Fabaceae) in New Zealand: taxonomy, distribution, and biogeography. New Zealand Journal of Botany 39: 17-53

This page last updated on 31 Oct 2014