Rhopalostylis is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of two species of palms

Arecaceae

Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...

 native to the South Pacific

Oceania

Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...

. Both are smooth-trunked, with regular ringed scars from fallen leaves. The leaves are 3–5 metres in length, and the leaf bases encircle the trunk.

Distribution

R. baueri occurs on Norfolk Island

Norfolk Island

Norfolk Island is a small island in the Pacific Ocean located between Australia, New Zealand and New Caledonia. The island is part of the Commonwealth of Australia, but it enjoys a large degree of self-governance...

 and the Kermadec Islands

Kermadec Islands

The Kermadec Islands are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga...

 northeast of New Zealand; the Kermadec Islands population, formerly separated as R. cheesemanii, was included in R. baueri

Rhopalostylis baueri

Rhopalostylis baueri is a species of palm native to Norfolk Island and to the Kermadec Islands . Norfolk Island is the type locality. The common names on Norfolk Island are 'Norfolk Island Palm' or 'Niau'...

in 2005 after comparison revealed no significant differences. R. sapida

Nikau

Nikau is a palm tree, the only palm endemic to New Zealand.-Etymology:Nīkau is a Māori word; in the closely related Eastern Polynesian languages of the tropical Pacific, it refers to the fronds or the midrib of the coconut palm.- Distribution:The Nikau palm is the only palm species endemic to...

, known as the Nikau Palm, is the only palm native to mainland New Zealand, and is found in lowland forests on the North Island

North Island

The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...

, in coastal areas of the South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

 as far south as Banks Peninsula

Banks Peninsula

Banks Peninsula is a peninsula of volcanic origin on the east coast of the South Island of New Zealand. It has an area of approximately and encompasses two large harbours and many smaller bays and coves...

, and on the Chatham Islands

Chatham Islands

The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...

 at 44 degrees south

44th parallel south

The 44th parallel south is a circle of latitude that is 44 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, the Indian Ocean, Australasia, the Pacific Ocean and South America....

. R. sapida thus has the southernmost range of any palm genus.

Classification

Sub-family: Arecoideae; Tribe: Areceae; Subtribe: Rhopalostylidinae

Rhopalostylidinae

Rhopalostylidinae is a botanical subtribe consisting of two genera of palms from Australia and New Zealand, Hedyscepe and Rhopalostylis...

. Rhopalostylis is closely related to the Lord Howe Island

Lord Howe Island

Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...

 genus Hedyscepe

Hedyscepe

Hedyscepe canterburyana, the Big Mountain Palm or Umbrella Palm, is the sole species in the genus Hedescepe of the Arecaceae family. It is endemic to Lord Howe Island, Australia and is threatened by habitat loss. It is a solitary palm with a distinct crownshaft, and bears unisexual flowers of both...

.