''Sphaeropteris medullaris'',

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

''Cyathea medullaris'', commonly known as mamaku or black tree fern, is a large

tree fern The tree ferns are arborescent (tree-like) ferns that grow with a trunk elevating the fronds above ground level, making them trees. Many extant tree ferns are members of the order Cyatheales, to which belong the families Cyatheaceae (scaly tree ...

up to 20 m tall. It is distributed across the south-west Pacific from

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

Pitcairn Island Pitcairn Island is the only inhabited island of the Pitcairn Islands, of which many inhabitants are descendants of mutineers of HMS ''Bounty''. Geography The island is of volcanic origin, with a rugged cliff coastline. Unlike many other ...

. Its other

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the C ...

names include katātā, kōrau, or pītau.

Distribution

''Sphaeropteris medullaris'' is common in lowland forest throughout the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

of New Zealand. In the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

its distribution is more localised. It is fairly common in wetter coastal areas, but rare in the drier eastern parts and absent in

Canterbury Canterbury (, ) is a City status in the United Kingdom, cathedral city and UNESCO World Heritage Site, situated in the heart of the City of Canterbury local government district of Kent, England. It lies on the River Stour, Kent, River Stour. ...

and

Otago Otago (, ; mi, Ōtākou ) is a region of New Zealand located in the southern half of the South Island administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local government reg ...

. In New Zealand it also occurs on the

Three Kings Islands 3 is a number, numeral, and glyph. 3, three, or III may also refer to: * AD 3, the third year of the AD era * 3 BC, the third year before the AD era * March, the third month Books * ''Three of Them'' (Russian: ', literally, "three"), a 1901 n ...

in the far north, on

Stewart Island/Rakiura Stewart Island ( mi, Rakiura, ' glowing skies', officially Stewart Island / Rakiura) is New Zealand's third-largest island, located south of the South Island, across the Foveaux Strait. It is a roughly triangular island with a total land ar ...

in the far south and in 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 ...

. Its distribution also includes

, the

Marquesas Islands The Marquesas Islands (; french: Îles Marquises or ' or '; Marquesan: ' ( North Marquesan) and ' ( South Marquesan), both meaning "the land of men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in th ...

Tahiti Tahiti (; Tahitian ; ; previously also known as Otaheite) is the largest island of the Windward group of the Society Islands in French Polynesia. It is located in the central part of the Pacific Ocean and the nearest major landmass is Austr ...

, the

Austral Islands The Austral Islands (french: Îles Australes, officially ''Archipel des Australes;'' ty, Tuha'a Pae) are the southernmost group of islands in French Polynesia, an overseas country of the French Republic in the South Pacific. Geographically, ...

, and

. It is not present in the Kermadecs.

Description

The trunk is black and covered with distinctive hexagonal stipe bases. The

frond A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the lar ...

s may be up to 5 m long, and arch upwards from the crown. Dead fronds are shed except in very young plants. The primary

pinnae The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna (Latin for "wing" or " fin", plural pinnae), a term that is used more in zoology. Structure The diagram shows the shape and location ...

are from 40 cm to 1 m long, and the undersides have scales with spines along their margins. As many as 40,000 leaflets have been counted on a single frond. The stipes are thick, black, very rough to the touch, and are similarly covered in black scales with marginal spines. ''S. medullaris'' can be readily distinguished from related species by the hexagonal stipe scars on the trunk, and by the scales with spines on their margins.

Cultivation

''Sphaeropteris medullaris'' will grow from fresh spores, but this is slow. Plants are easy to transplant when they are young. It is also possible to plant newly felled trunks which will generally sprout again, provided they are watered with care. They are hardy in various conditions once established. It has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

as an ornamental.

Uses

Tree fern trunks, including those of ''S. medullaris'', have been used as rough building material and also for makeshift trackwork. The 1889 book ''The Useful Native Plants of Australia'' records that Indigenous Australians ate the pith of this fern tree which contained a certain amount of starch similar to sago.

References

Bibliography

* C.Michael Hogan. 2010
''Fern''. Encyclopedia of Earth. eds. Saikat Basu and C.Cleveland. National Council for Science and the Environment
Washington DC. {{Taxonbar, from1=Q15600236, from2=Q5197621 medullaris Ferns of Australasia Ferns of Oceania Ferns of New Zealand Flora of the Tubuai Islands Trees of New Zealand Trees of mild maritime climate Garden plants of New Zealand Ornamental trees