K?whai (M?ori pronunciation: [k?:?ai] or [k?:fai]) are small woody legume trees within the genus Sophora that are native to New Zealand. There are eight species, with Sophora microphylla and S. tetraptera being the most recognised as large trees. Their natural habitat is beside streams and on the edges of forest, in lowland or mountain open areas. K?whai trees grow throughout the country and are a common feature in New Zealand gardens. Outside of New Zealand, k?whai tend to be restricted to mild temperate maritime climates.
The blooms of the k?whai are widely regarded as being New Zealand's national flower, although they have no official status as such.
The word k?whai is also used in the M?ori language for the colour yellow, because of the colour of the flowers.
Video K?whai
Species
The eight species of k?whai are:
- Sophora chathamica, coastal k?whai
- Sophora fulvida, Waitakere k?whai
- Sophora godleyi, Godley's k?whai
- Sophora longicarinata, limestone k?whai
- Sophora microphylla, small-leaved k?whai
- Sophora molloyi, Cook Strait k?whai
- Sophora prostrata, prostrate k?whai
- Sophora tetraptera, large-leaved k?whai
Maps K?whai
Description and ecology
Most species of k?whai grow to around 8 m high and have fairly smooth bark with small leaves. S. microphylla has smaller leaves (0.5-0.7 cm long by 0.3-0.4 cm wide) and flowers (2.5-3.5 cm long) than S. tetraptera, which has leaves of 1-2 cm long and flowers that are 3-5 cm long.
The very distinctive seed pods that appear after flowering are almost segmented, and each contains six or more smooth, hard seeds. Most species have yellow seeds, but Sophora prostrata has black ones. The seeds of Sophora microphylla can be very numerous and the presence of many hundreds of these distinctively yellow seeds on the ground quickly identifies the presence of a nearby k?whai tree. Many species of k?whai are semi-deciduous and lose most of their leaves immediately after flowering in October or November, but quickly produce new leaves. Flowering of k?whai is staggered from July through to November, meaning each tree will get attention from birds such as tui, wood pigeon and bellbird. Tui are very attracted to k?whai and will fly long distances to get a sip of its nectar.
The wood of k?whai is dense and strong and has been used in the past for tools and machinery.
Sophora is one of the four genera of native legumes in New Zealand; the other three are Carmichaelia, Clianthus, and Montigena.
Cultivation
K?whai can be grown from seed or tip cuttings in spring and autumn. The dark or bright yellow seeds germinate best after chitting and being soaked in water for several hours. They can also benefit from a several minute submersion in boiling water to soften the hard shell and then being kept in the same water, taken off boil, for several hours to soak up the water. Young k?whai are quite frost tender, so cuttings or seedlings should be planted in their second year when they are 30 cm or higher.
If grown from seed, k?whai can take many years to flower, the number of years varies depending on the species.
S. prostrata, sometimes called "little baby", is used as a bonsai tree. It grows up to two metres high, has zigzaging stems, and sparse smallish leaves.
Dangers
All parts of the k?whai, but particularly the seeds, are poisonous to humans. However, there do not appear to have been any confirmed cases in humans of severe poisoning following ingestion of k?whai in New Zealand.
Traditional M?ori use
Traditionally the M?ori used the flexible branches as a construction material in their houses and to snare birds. The k?whai flowers were a source of yellow dye.
M?ori also used the k?whai tree as medicine. The bark was heated in a calabash with hot stones, and made into a poultice to treat wounds or rubbed on a sore back or made into an infusion to treat bruising or muscular pains. If someone was bitten by a seal, an infusion (wai k?whai) was prepared from k?whai and applied to the wounds and the patient was said to recover within days.
References
Source of article : Wikipedia
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