Biology:Metrosideros umbellata

Short description: Species of tree

Southern rātā
Southern rātā near Franz Josef Glacier
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Rosids
Order:	Myrtales
Family:	Myrtaceae
Genus:	Metrosideros
Species:	M. umbellata
Binomial name
Metrosideros umbellata Cav.
Distribution of M. umbellata in mainland New Zealand. Auckland Islands not shown.
Synonyms
Metrosideros lucida (G. Forst) A. Rich

Metrosideros umbellata, the southern rātā, is a tree endemic to New Zealand. It grows up to 15 metres (49 ft) or more tall with a trunk up to 1 metre (3 ft 3 in) or more in diameter. It produces masses of red flowers in summer. Unlike its relative, northern rātā, this species rarely grows as an epiphyte.

Description

The flowers of southern rātā are scarlet, with stamens about 2 centimetres (0.79 in) long. White or yellow flowers are also known. Flowering usually occurs between December and February, but this depends on local conditions. Leaves are from 3 centimetres (1.2 in) to 6 centimetres (2.4 in) long, and are sharply pointed. The wood is hard, dense, and very strong. The bark is rough and flaky and provides an ideal stratum for the roots of epiphytic plants such as Astelia species and Freycinetia banksii (Kiekie). Southern rātā is a major source of honey on the West Coast of the South Island. Kākā, tūī, and bellbirds visit rātā to take advantage of the abundant nectar.

Southern rātā growing at its southern limits in the Auckland Islands at 50°S

Distribution

It prefers cooler regions with high rainfall and is particularly common along the west coast of the South Island where its nectar is the main source of a locally produced rātā honey. Southern rātā is the most widespread of the New Zealand tree rātā species. It is locally present in the North Island from latitude 36° southwards, is more common in western parts of the South Island but absent from much of the east, and is common on Stewart Island (47°S) and in the Auckland Islands, where it reaches its southern limit at just over 50°S.

Conservation

Although southern rātā is not regarded as threatened, it is rather uncommon in the North Island, and in certain areas it is threatened by possum browse. In the Tararua range, southern rātā populations appear to have been replaced by a population consisting of hybrids between northern and southern rātā.

Project Crimson is a charitable trust that promotes conservation of rātā as well as the related pōhutukawa.

Cultivation

Southern rātā is a beautiful specimen tree, but growth can be slow unless it is grown in ideal conditions with moist soil. It is easily grown from fresh seed. While it is possible to grow the tree from softwood or semi-hardwood cuttings, these often prove reluctant to strike roots. It is ideal for coastal environments because it has a good resistance to wind and salt.

At least 16 cultivars of southern rātā have been released. There are also known cultivars of hybrids between southern rātā and pōhutukawa, and between northern rātā and southern rātā. Known cultivars include:

Cultivar name	Year introduced	Flower colour	Introduced by	Notes
M. umbellata ‘Alba’	mid-1980s	White/cream	Denis Hughes	Leaves are a paler lemon-green then standard plants. Sourced from Soaker Hill in the Catlins, South Otago.
M. umbellata ‘Christmas Dream’	Late 1970s	Red	Denis Hughes	Sourced from Lake Manapouri.
M. umbellata ‘Denniston Yellow’	1995	Sulphur Yellow	Deane Keir	Sourced from the Denniston Plateau.
M. umbellata ‘Fireball’	1993	Bright crimson	Deane Keir	Sourced from the Stockton Plateau at a place called Burning Mine.
M. umbellata ‘Firecracker’	1995	Deep red	Jeff Elliott	Sourced from Whanganui Inlet, North-West Nelson.
M. umbellata ‘Gold Beacon’	-	Sulphur Yellow	Les Cleveland	Sourced from the Otira Gorge.
M. umbellata ‘Gold Nugget’	1992	Red	Joe Cartman	Golden new leaves with thin red leaf margins. Sourced from side-shoot of M. umbellata ‘Harlequin’. Also sold as M. umbellata ‘Lownug’.
M. umbellata ‘Harlequin’	md-1980s	Red	Joe Cartman	Variegated cultivar with yellow leaf margins. Sourced from Nugget Point.
M. umbellata ‘Kaka’	late-1990s	Pink	Denis Hughes	Sourced from Kaka Point, Otago.
M. umbellata ‘Moonlight’	2001	Red	Pattersons Nurseries	Reverse variegated cultivar. Sourced from side-shoot of M. umbellata ‘Gold Nugget’. Also sold as M. umbellata ‘Lowmoo’.
M. umbellata ‘Mt Augustus’	Late-1970s	Red	Louise Salmond	Sourced from the Stockton Plateau at a place called Mt Augustus.
M. umbellata ‘Red Tips’	Mid-1990s	Red	Les Cleveland	New leaves have a red tip. Sourced from an island in Lake Wānaka.
M. umbellata ‘St Nicholas’	Late 1970s	Red	Denis Hughes	Sourced from Lake Manapouri.
M. umbellata ‘Scarlet Beacon’	2002	Red	Les Cleveland	-
M. umbellata ‘Silver Beacon’	Mid-1990s	Red	Les Cleveland	New leaves have a silvery tip. Sourced from an island in Lake Wānaka.
M. umbellata ‘Sparrow’s Hybrid’	1994	Red	Mr Sparrow	Sourced from the banks of the Avon River in Christchurch, between Madras and Manchester Streets. Source material provided by Mr Sparrow, a customer of the nursery. Despite the name, this cultivar is not a hybrid.
¤ Metrosideros ‘Cleveland Red’	late-1990s	Scarlet	Les Cleveland	Deliberate interspecific hybrid.
¤ Metrosideros ‘Maungapiko’	1985	Bright crimson	Graeme Platt	Sourced from Maungapiko Track, Great Barrier Island.
¤ Metrosideros ‘Rustic Beauty’	1985	-	Les Cleveland	Deliberate interspecific hybrid.
∞ Metrosideros ‘Sentinel Flame’	2007	Bright red	Graeme Platt / Vibrant Earth nursery	Sourced from either Great Barrier Island or North-West Nelson.

∞ Hybrid of southern rātā and northern rātā
¤ Hybrid of southern rātā and pōhutukawa

See also

• Metrosideros excelsa, pōhutukawa
• Metrosideros robusta, northern rātā
• Metrosideros bartlettii, Bartlett's rātā
• Metrosideros parkinsonii, Parkinson's rātā

References

• "Metrosideros umbellata". Flora of New Zealand. http://floraseries.landcareresearch.co.nz/pages/Taxon.aspx?id=_42b6cbd7-e582-4f4d-ba21-7d69070266dd&fileName=Flora%201.xml. Retrieved 2007-06-09. 
• "Metrosideros umbellata". New Zealand Plant Conservation Network. http://www.nzpcn.org.nz/flora_details.asp?ID=978. Retrieved 2010-10-02. 
• "Southern Rata Fact Sheet". Project Crimson. Archived from the original on 2013-02-08. https://web.archive.org/web/20130208220320/http://www.projectcrimson.org.nz/images/file/Fact%20Sheets/Fact-Sheet-Southern-Rata.pdf. Retrieved 2013-07-30. 

Further reading

• Salmon, J.T., 1986. The Native Trees of New Zealand. Wellington: Heinneman Reed.
• Simpson, P., 2005. Pōhutukawa & Rātā: New Zealand's Iron-Hearted Trees. Wellington: Te Papa Press.

External links

• Project Crimson

Wikidata ☰ Q1461888 entry