Rhopalostylis is a genus of two species of palms in the family Arecaceae, subfamily Arecoideae, tribe Areceae, subtribe Rhopalostylidinae. The genus is native to the South Pacific and is closely related to Hedyscepe, the sole palm of Lord Howe Island.
Both species are smooth-trunked with regular ringed scars left by fallen leaves. The leaves reach 3–5 m in length and the leaf bases encircle the trunk, forming a prominent crownshaft. In R. sapida, the trunk grows to 15 m; the crownshaft is 0.6–1 m long, dark green and bulging; fronds carry leaflets to 1 m that are closely set and sometimes overlapping. Flowers are sessile and unisexual, lilac to pink, and the fruit is elliptic-oblong, about 10 × 7 mm, with red flesh.
The genus contains two species: Rhopalostylis sapida (the nikau palm) and Rhopalostylis baueri (the Norfolk palm). R. sapida is the only palm native to mainland New Zealand, and its range extending to the Chatham Islands at 44°S makes Rhopalostylis the southernmost-ranging palm genus in the world.
Etymology
The genus name Rhopalostylis derives from Greek meaning "club style" (rhopalon = club, stylis = style), referring to the club-like shape of the style. The species epithet sapida is Latin for "savoury" or "pleasant-tasting."
Distribution
Rhopalostylis sapida (nikau) is endemic to New Zealand, occurring throughout the North Island, in the South Island from the Marlborough Sounds and Nelson south to Okarito on the west coast and Banks Peninsula on the east, and on the Chatham and Pitt Islands at 44°S — giving the genus the southernmost natural range of any palm. R. baueri occurs on Norfolk Island and the Kermadec Islands northeast of New Zealand; the Kermadec Islands population (formerly treated as R. cheesemanii) was synonymised with R. baueri in 2005 after comparison revealed no significant differences.
Ecology
Rhopalostylis sapida is primarily a species of coastal to lowland forest in the warmer parts of New Zealand. It flowers from November to April and fruits from February to November. Its wetland indicator status is FACU (facultative upland), meaning it occasionally occurs in hydrophytic settings but is predominantly an upland forest species.
Cultivation
Rhopalostylis sapida is widely available from retail plant nurseries in New Zealand. It performs well as a container plant provided the taproot is left intact, and can be transplanted successfully. The species is considered quite hardy and shows considerable natural variation, suggesting potential for horticultural selection.
Propagation
Nikau palms are relatively easy to grow from seed. Fruits should be soaked in water for several days, then lightly scrubbed to remove the flesh. Seeds are placed in sealed plastic bags in half shade until germination begins. Germinating seeds should be planted in deep, narrow pots to accommodate the taproot, and root disturbance should be minimised.
Conservation
Rhopalostylis sapida is assessed as "Not Threatened" under New Zealand's Threat Classification System, a status maintained across assessments in 2004, 2009, 2012, 2017, and 2023. It is also assessed as Regionally Not Threatened in the Auckland region (2025).
