Rhopalostylidinae
Encyclopedia
Rhopalostylidinae is a botanical subtribe consisting of two genera of palms from Australia
and New Zealand
, Hedyscepe
and Rhopalostylis
. These two genera were formerly included in Archontophoenicinae
, to which they are morphologically
similar (Dowe 2010:233), until a revision in (Dransfield, Uhl et al., 2005).
s and strictly pinnate
leaves with generally short and massive petioles. The inflorescences are branched to two or three orders, with the prophyll and penduncular bracts similar (Uhl and Dransfield 1987:367).
, the Norfolk Palm or Niau, from Norfolk Island
, Australia, and Raoul Island
in the Kermadec group
north of New Zealand, and R. sapida, the Nikau Palm, from New Zealand. The leaves of Rhopalostylis tend to be held rigidly upright, especially in R. sapida from the northern North Island
, making the palm somewhat resemble a feather duster.
Hedyscepe contains a single species, H. canterburyana the Big Mountain Palm, which grows on mountain cliffs overlooking the sea on Lord Howe Island
, Australia. However a genetic study in 2006 throws doubt on the validity of Hedescepe as a member of the Rhopalostylidinae. The study revealed a "curious relationship between Hedyscepe and the clade Alloschmidia
and Basselinia
which is highly supported by the combined analysis (88 BP) and thus contradicts the monophyly of the Rhopalostylidinae" (Norup, Dransfield et al., 2006:1075). The genera Alloschmidia
and Basselinia
are endemic to New Caledonia
.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, 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...
and Rhopalostylis
Rhopalostylis
Rhopalostylis is a genus of two species of palms native to the South Pacific. 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...
. These two genera were formerly included in Archontophoenicinae
Archontophoenicinae
Archontophoenicinae is a botanical subtribe consisting of four genera of palms, namely Archontophoenix from Queensland and New South Wales and Actinokentia, Chambeyronia and Kentiopsis from New Caledonia.-Description:...
, to which they are morphologically
similar (Dowe 2010:233), until a revision in (Dransfield, Uhl et al., 2005).
Description
The palms in this subtribe are medium-sized palms, with well-developed, distinct crownshaftCrownshaft
An elongated circumferential leaf base formation present on some species of palm is called a crownshaft.The leaf bases of some pinnate leaved palms form a sheath at the top of the trunk surrounding the bud where all the subsequent leaves are formed.The crownshaft...
s and strictly pinnate
Pinnate
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...
leaves with generally short and massive petioles. The inflorescences are branched to two or three orders, with the prophyll and penduncular bracts similar (Uhl and Dransfield 1987:367).
Genera
The genus Rhopalostylis contains two species, R. baueriRhopalostylis 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'...
, the Norfolk Palm or Niau, from 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...
, Australia, and Raoul Island
Raoul Island
Anvil-shaped Raoul Island , the largest and northernmost of the main Kermadec Islands, , has been the source of vigorous volcanic activity during the past several thousand years that was dominated by dacitic explosive eruptions.The area of the island, including fringing islets and rocks...
in the Kermadec group
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...
north of New Zealand, and R. sapida, the Nikau Palm, from New Zealand. The leaves of Rhopalostylis tend to be held rigidly upright, especially in R. sapida from the northern 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...
, making the palm somewhat resemble a feather duster.
Hedyscepe contains a single species, H. canterburyana the Big Mountain Palm, which grows on mountain cliffs overlooking the sea on 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...
, Australia. However a genetic study in 2006 throws doubt on the validity of Hedescepe as a member of the Rhopalostylidinae. The study revealed a "curious relationship between Hedyscepe and the clade Alloschmidia
Alloschmidia
Alloschmidia glabrata is a species of palm tree in the monotypic genus Alloschmidia.It is found only in New Caledonia....
and Basselinia
Basselinia
Basselinia is a genus of flowering plant in the Arecaceae family.It contains the following species:* Basselinia favieri* Basselinia humboldtiana* Basselinia iterata* Basselinia porphyrea* Basselinia tomentosa...
which is highly supported by the combined analysis (88 BP) and thus contradicts the monophyly of the Rhopalostylidinae" (Norup, Dransfield et al., 2006:1075). The genera Alloschmidia
Alloschmidia
Alloschmidia glabrata is a species of palm tree in the monotypic genus Alloschmidia.It is found only in New Caledonia....
and Basselinia
Basselinia
Basselinia is a genus of flowering plant in the Arecaceae family.It contains the following species:* Basselinia favieri* Basselinia humboldtiana* Basselinia iterata* Basselinia porphyrea* Basselinia tomentosa...
are endemic to New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
.