| Nikau | ||||||||||||||||||
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| Rhopalostylis sapida H.Wendl. & Drude |
Nikau (Rhopalostylis sapida) is a palm tree endemic to New Zealand.
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The Nikau is the only palm species native to mainland New Zealand. Its natural range is coastal and lowland forest on the North Island, and on the South Island as far south as Okarito (43°20′S) in the west and Banks Peninsula (43°5′S) in the east. It also occurs on Chatham Island and Pitt Island/Rangiauria to the south-east of New Zealand, where it is the world's southernmost palm at 44° 18'S latitude. Nīkau is a Māori word; in related Polynesian languages of the tropical Pacific, it refers to the fronds or the midrib of the coconut palm.
The Nikau grows up to 15 m tall, with a stout green trunk which bears grey-green leaf scars. The trunk is topped by a smooth bulging crownshaft up to 1m long. The fronds are up to 3m long, and the closely-set, sometimes overlapping leaflets are up to 1 m long. The inflorence is multi-branched and from 200 to 400 mm long. The tightly packed flowers are unisexual and coloured lilac to pink. Male flowers are borne in pairs, and have 6 stamens. The female flowers are solitary. The fruit is elliptic or oblong, and generally measures about 10 by 7 mm, and is red when ripe. The Nikau produces flowers between November and April, and fruits ripen from February to November, taking almost a year to fully ripen. These are a favorite food of the Kererū, the native wood pigeon.
The Nikau is easy to grow from seed if the fruit is soaked in water for a few days and then gently scrubbed to remove the flesh. The seed will then germinate readily if placed in sealed plastic bags in semi-shade, after which they can be planted in deep pots. The pots should be tall and narrow to provide room for the taproot and to lessen the likelihood of root damage when transplanting. Transplanting is generally successful if the taproot is left intact. The Nikau makes an excellent pot plant, and is quite hardy. It tends to be slow-growing.
Nikau palms show considerable variation in the wild. Plants from the South Island and the offshore islands of the North Island have larger, more gracefully arching fronds and are popular in cultivation. The Chatham Islands form is particularly different, having a distinct juvenile form and larger fruits, and a thicker covering of fine hairs on the fronds. More research is needed into its precise relationship with the mainland form. The New Zealand Nikau palm is very similar to Rhopalostylis baueri of the Kermadecs and Norfolk Island, which can be distinguished by its more rounded or oval fruits, and by its leaflets which are broader than those found in most populations of R. sapida.
