Anogramma ascensionis
Encyclopedia
Anogramma ascensionis is a species of fern
in the Pteridaceae
family that is endemic to Ascension Island
, a volcanic island in the South Atlantic Ocean. It is one of eight putative species in the Anogramma
genus. It was thought to have become extinct due to habitat loss, until four plants were found on the island in 2010. Over 60 specimens were then successfully cultivated at Royal Botanic Gardens, Kew
and on Ascension Island. It is now classified as Critically Endangered.
The small fern has delicate yellow-green leaves which appear similar to small sprigs of parsley
. It was first recorded in 1842 by an amateur botanist, Dr A.B. Curror, and then officially described and named by Joseph Dalton Hooker
after a visit he made to the island in 1843. It is endemic to the steep slopes of Green Mountain
on the island. Another specimen was recorded in 1889, with few or no reports of specimens again until 1958, when a British scientist collected one on the north slope of the mountain. Further searches were conducted in 1976, 1986 and 1995 but were unsuccessful, and in 2003 it was officially declared extinct.
There are ten species of plants endemic to Ascension Island, with seven of them still known to survive. The island lost much of its native habitat due to invasive animals and plants, beginning with goats introduced in the 16th century by Portuguese explorers. Other non-native animals, including rabbits, sheep, donkeys, and rats—along with over 200 non-native plant species—have destroyed much of the original habitat and plants.
The introduction of non-native plants and animals was greatly hastened beginning in 1847, when Joseph Dalton Hooker advised the Royal Navy to import plants to the island to change the dry cinder soil and arid climate. Kew Gardens, who's director at the time was Hooker's father, helped ship trees to Ascension Island beginning in 1850. Green Mountain in particular was transformed through their efforts. Competition from invasive and non-native maidenhair fern (Adiantum) is believed by scientists to be partly responsible for the demise of A. ascensionis.
A. ascensionis was rediscovered during a routine plant survey being performed by a team from the Ascension Island Government's Conservation Department. Because it was found growing in dry rock, on a very steep ridge, the four plants had to be watered and kept alive long enough to produce spores. Two of the plants produced spores before they died. After harvesting, the spores were quickly airlifted to Kew Gardens, where they were placed in a sterile environment to produce sporelings. Sixty new ferns were raised at Kew, along with more on Ascension Island. Since then, a small number of plants were discovered growing near the original four.
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
in the Pteridaceae
Pteridaceae
Pteridaceae is a large family of ferns in the order Pteridales. Members of the family have creeping or erect rhizomes and are mostly terrestrial or epipetric...
family that is endemic to Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
, a volcanic island in the South Atlantic Ocean. It is one of eight putative species in the Anogramma
Anogramma
Anogramma is a genus of fern in the Pteridaceae family. It contains 8 putative species:* Anogramma ascensionis Diels – endemic to Ascension Island, South Atlantic Ocean.* Anogramma caespitosa – only found on Mount Kilimanjaro, Tanzania....
genus. It was thought to have become extinct due to habitat loss, until four plants were found on the island in 2010. Over 60 specimens were then successfully cultivated at Royal Botanic Gardens, Kew
Royal Botanic Gardens, Kew
The Royal Botanic Gardens, Kew, usually referred to as Kew Gardens, is 121 hectares of gardens and botanical glasshouses between Richmond and Kew in southwest London, England. "The Royal Botanic Gardens, Kew" and the brand name "Kew" are also used as umbrella terms for the institution that runs...
and on Ascension Island. It is now classified as Critically Endangered.
The small fern has delicate yellow-green leaves which appear similar to small sprigs of parsley
Parsley
Parsley is a species of Petroselinum in the family Apiaceae, native to the central Mediterranean region , naturalized elsewhere in Europe, and widely cultivated as an herb, a spice and a vegetable.- Description :Garden parsley is a bright green hairless biennial herbaceous plant in temperate...
. It was first recorded in 1842 by an amateur botanist, Dr A.B. Curror, and then officially described and named by Joseph Dalton Hooker
Joseph Dalton Hooker
Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...
after a visit he made to the island in 1843. It is endemic to the steep slopes of Green Mountain
Green Mountain
Green Mountain is a common name for "The Peak", the highest point, on Ascension Island which has gained some fame for claims that it is one of very few large-scale artificial forests.-History and Vegetation:...
on the island. Another specimen was recorded in 1889, with few or no reports of specimens again until 1958, when a British scientist collected one on the north slope of the mountain. Further searches were conducted in 1976, 1986 and 1995 but were unsuccessful, and in 2003 it was officially declared extinct.
There are ten species of plants endemic to Ascension Island, with seven of them still known to survive. The island lost much of its native habitat due to invasive animals and plants, beginning with goats introduced in the 16th century by Portuguese explorers. Other non-native animals, including rabbits, sheep, donkeys, and rats—along with over 200 non-native plant species—have destroyed much of the original habitat and plants.
The introduction of non-native plants and animals was greatly hastened beginning in 1847, when Joseph Dalton Hooker advised the Royal Navy to import plants to the island to change the dry cinder soil and arid climate. Kew Gardens, who's director at the time was Hooker's father, helped ship trees to Ascension Island beginning in 1850. Green Mountain in particular was transformed through their efforts. Competition from invasive and non-native maidenhair fern (Adiantum) is believed by scientists to be partly responsible for the demise of A. ascensionis.
A. ascensionis was rediscovered during a routine plant survey being performed by a team from the Ascension Island Government's Conservation Department. Because it was found growing in dry rock, on a very steep ridge, the four plants had to be watered and kept alive long enough to produce spores. Two of the plants produced spores before they died. After harvesting, the spores were quickly airlifted to Kew Gardens, where they were placed in a sterile environment to produce sporelings. Sixty new ferns were raised at Kew, along with more on Ascension Island. Since then, a small number of plants were discovered growing near the original four.
External links
- Science In Action BBC World Service 25 June 2010