''Dracophyllum arboreum'', commonly known as Chatham Island grass tree and tarahinau (
Moriori
The Moriori are the native Polynesian people of the Chatham Islands (''Rēkohu'' in Moriori; ' in Māori), New Zealand. Moriori originated from Māori settlers from the New Zealand mainland around 1500 CE. This was near the time of the ...
), is a species of tree in the heath family
Ericaceae
The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...
. Endemic to the
Chatham Islands
The Chatham Islands ( ) (Moriori: ''Rēkohu'', 'Misty Sun'; mi, Wharekauri) are an archipelago in the Pacific Ocean about east of New Zealand's South Island. They are administered as part of New Zealand. The archipelago consists of about te ...
of New Zealand, it reaches a height of and has leaves that differ between the juvenile and adult forms.
''D. arboreum'' has wide light green leaves in its juvenile form, which become thin needles as it gains maturity. Flowering occurs from November through to February, yielding small white flowers which later become tiny brown fruit. It inhabits many different types of
vegetation communities from near sea level to , including swamps, cliffs, bogs, and shrublands. It has a range restricted to three Islands some east of New Zealand: the
Chatham
Chatham may refer to:
Places and jurisdictions Canada
* Chatham Islands (British Columbia)
* Chatham Sound, British Columbia
* Chatham, New Brunswick, a former town, now a neighbourhood of Miramichi
* Chatham (electoral district), New Brunswic ...
,
Pitt, and
Rangatira
In Māori culture, () are tribal chiefs, the hereditary Māori leaders of a hapū. Ideally, rangatira were people of great practical wisdom who held authority () on behalf of the tribe and maintained boundaries between a tribe's land and that ...
Islands.
It was first described by the British botanist
Joseph Hooker
Joseph Hooker (November 13, 1814 – October 31, 1879) was an American Civil War general for the Union, chiefly remembered for his decisive defeat by Confederate General Robert E. Lee at the Battle of Chancellorsville in 1863.
Hooker had serv ...
in 1864 as a
variety
Variety may refer to:
Arts and entertainment Entertainment formats
* Variety (radio)
* Variety show, in theater and television
Films
* ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont
* ''Variety'' (1935 film), ...
of the species ''
D. latifolium,'' but was first given the status as a species itself in 1902 by the New Zealand botanist
Leonard Cockayne
Leonard Cockayne (7 April 1855 – 8 July 1934) is regarded as New Zealand's greatest botanist and a founder of modern science in New Zealand.
Biography
He was born in Sheffield, England where he attended Wesley College. He travelled to Austra ...
. Another New Zealand botanist,
Thomas Cheeseman
Thomas Frederick Cheeseman (8 June 184515 October 1923) was a New Zealand botanist. He was also a naturalist who had wide-ranging interests, such that he even described a few species of sea slugs (marine gastropod molluscs).
Biography
Chees ...
, demoted it once again to a variety in 1925, this time of ''
D. scoparium,'' but this change has not been recognised by other botanists and institutions. The New Zealand naturalist
Walter Oliver
Walter Reginald Brook Oliver (7 September 1883 – 16 May 1957) was a New Zealand naturalist, ornithologist, malacologist, and museum curator.
Biography
Born in Launceston, Tasmania, Oliver emigrated with his family to New Zealand in 1896, set ...
placed it in the
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
''Oreothamnus'' in 1928. A
cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
analysis in 2010 revealed through genetic sequencing that it was part of a
paraphyletic group
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
and not directly related to ''
D. patens,'' as Oliver had suggested in his 1952 supplement, but to ''D. scoparium,'' as he had originally thought.
Description
''Dracophyllum arboreum'' is a tree which grows to a height of . It has greyish brown bark with new growth a reddish brown to yellow. Its leaves are dimorphic, meaning they differ between the juvenile and adult stages dramatically. The juvenile leaves are green and leathery. The juvenile leaves are also completely hairless, except for dense, tiny hairs along the edges. The adult leaves, on the other hand, are narrow, , and needle-like. They are
hairless
Hairless, also known as H, is a well-characterized Drosophila gene. Since Hairless is a dominant loss of function mutation, many mutations to Hairless are embryonic lethal, but there are several viable hairless mutants. This specific Drosophila ...
, except for a margin that is covered with many tiny hairs, as well as a tuft of hair at the base of the top side.
Flowering occurs from November to February, producing spiked terminal
inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
s (flower clusters) with 4 – 9 flowers on each. They grow off of lateral