''Ptisana salicina'', or king fern, is a species of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

native to Norfolk Island,

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and the South Pacific. Large and robust with a distinctive tropical appearance, it has fronds up to 5 metres (16 feet +/-) tall that arise from a starchy base that was a traditional food for the Maori. It has several other common names including para, tawhiti-para, and horseshoe fern.

Distribution

King fern is indigenous to Norfolk Island (the type locality), New Zealand, New Caledonia,

Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , lan ...

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 ...

Society Islands The Society Islands (french: Îles de la Société, officially ''Archipel de la Société;'' ty, Tōtaiete mā) are an archipelago located in the South Pacific Ocean. Politically, they are part of French Polynesia, an overseas country of the ...

and the

Marquesas 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 t ...

. It is closely related to ''Ptisana smithii'' of Vanuatu, Fiji, the Solomon Islands, Samoa and Tonga. In New Zealand it is found in lowland areas on the north-western half of the North Island from inland

Wanganui Whanganui (; ), also spelled Wanganui, is a city in the Manawatū-Whanganui region of New Zealand. The city is located on the west coast of the North Island at the mouth of the Whanganui River, New Zealand's longest navigable waterway. Whang ...

northwards. It is most abundant in the western

Waikato Waikato () is a local government region of the upper North Island of New Zealand. It covers the Waikato District, Waipa District, Matamata-Piako District, South Waikato District and Hamilton City, as well as Hauraki, Coromandel Peninsul ...

, where it is found in forests and forest remnants. It prefers limestone-rich soils, including the entrances to caves and shady stream sides. It often grows in New Zealand association with parataniwha (''

Elatostema rugosum ''Elatostema rugosum'', commonly known as parataniwha or New Zealand begonia is a herbaceous ground cover plant that is endemic to New Zealand. ''Elatostema rugosum'' grows up to high in wet, shaded places such as gullies and streamsides. It ha ...

'') and supplejack ('' Ripogonum scandens'').

Threats

King fern is in serious decline in New Zealand, seriously threatened throughout its range by feral and domestic cattle, wild pigs and goats. Large plants no longer exist except in areas where there has been rigorous control of animals, or in inaccessible cave entrances or steep-sided gorges in karst areas. Another serious threat comes from plant collectors who are said to have wiped out several large populations in the

Kawhia Kawhia Harbour (Maori: ''Kāwhia'') is one of three large natural inlets in the Tasman Sea coast of the Waikato region of New Zealand's North Island. It is located to the south of Raglan Harbour, Ruapuke and Aotea Harbour, 40 kilometres southw ...

district.

Description

The green cane-like leaf stalks are 1 to 3 metres long. The young fronds are protected as they uncoil by a large ear-shaped basal lobe at the base called a

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

. The glossy, dark green fronds are 4 metres, sometimes 5 metres long and 2 metres wide. The juvenile fronds are less robust, and wilt quickly if exposed to sunlight. In the Kawhia area, a distinctive form is sometimes encountered, which has crested tips on the adult leaflets. Specimens of suitable age may produce spores at any time in the year.

Propagation

Propagation is difficult. King fern can be grown from spores, but this is extremely slow. It is sometimes offered for sale in nurseries that specialise in native plants.

References

* {{Taxonbar, from=Q7257082 Marattiidae Ferns of Australasia Ferns of Australia Ferns of New Zealand Flora of the Tubuai Islands Flora of the south-central Pacific

Distribution

Threats

Description

Propagation

See also

References