Biology
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англиски
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добавил Arkive
Ferns are 'primitive' plants that spread by releasing spores rather than by producing flowers and fruits. The distinctive frond stage of the fern lifecycle is asexual; spores are released from the fronds, which then germinate into minuscule heart-shaped structures known as 'prothalli'. It is here that the sexual stage of the lifecycle occurs; male and female organs on the prothallus produce sperm and eggs respectively. If the female eggs are fertilised successfully, a new fern plant will begin to grow and the cycle starts again (4).
Conservation
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англиски
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Marattia purpurascens is the largest of Ascension Island's native plants and its population is being monitored by Ascension Conservation (3).
Description
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англиски
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This large fern has broad, sturdy fronds that can reach up to 1 metre in length (2). The dark green fronds are divided into as many as 3 branches, each with 6 pairs of leaflets, known as 'pinnules' (2). Ferns produce spores and these develop within structures known as 'sori', which line the edges of the pinnules (2).
Habitat
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англиски
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Marattia purpurascens is found growing in open grassland on the exposed side of Green Mountain and amongst bamboo thickets near to the summit (3).
Range
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англиски
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Endemic to Ascension Island in the South Atlantic, this fern is today restricted to a single population on Green Mountain (3).
Status
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англиски
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Classified as Near Threatened (NT) in 2003 under IUCN Red List categories (3).
Threats
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англиски
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The population of Marattia purpurascens is now believed to be more stable than was previously feared and the species has been downgraded to Near Threatened under IUCN categories (3). Long-term threats to its survival do exist however, in the form of competition with introduced species and grazing by sheep, although this is not currently a common occurrence (3).
Ptisana purpurascens
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англиски
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добавил wikipedia EN
Ptisana purpurascens is a large fern belonging to the botanical family Marattiaceae. It has a globular rhizome with stipule-like fleshy outgrowths. The leaves are dark green, twice pinnate and up to 1 metre long. Every pinnule has up to six pairs of leaflets. The petioles are dark-purplish, hence the name 'purpurascens' meaning 'becoming purple'. The sporangia are fused in all Ptisana into a bivalvate synangium.
Conservation plans have been proposed for Ptisana purpurascens, an endemic of the distant Ascension Island in the South Atlantic, where a single population remains on Green Mountain. While the mature plants are still present in large numbers, long-term threats to its survival exist in the form of competition with alien invasive species like introduced plants such as Buddleja madagascariensis and grazing by sheep and rabbits. Successful reproduction is very rare, making the species highly endangered.
References
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Gray, A., Palembe, T., Stroud, S. 2005. The conservation of the endemic vascular flora of Ascension Island and threats from alien species. Oryx 39: 449–453. [1]
- See the ARKive site for additional information [2]
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Ptisana purpurascens: Brief Summary
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англиски
)
добавил wikipedia EN
Ptisana purpurascens is a large fern belonging to the botanical family Marattiaceae. It has a globular rhizome with stipule-like fleshy outgrowths. The leaves are dark green, twice pinnate and up to 1 metre long. Every pinnule has up to six pairs of leaflets. The petioles are dark-purplish, hence the name 'purpurascens' meaning 'becoming purple'. The sporangia are fused in all Ptisana into a bivalvate synangium.
Conservation plans have been proposed for Ptisana purpurascens, an endemic of the distant Ascension Island in the South Atlantic, where a single population remains on Green Mountain. While the mature plants are still present in large numbers, long-term threats to its survival exist in the form of competition with alien invasive species like introduced plants such as Buddleja madagascariensis and grazing by sheep and rabbits. Successful reproduction is very rare, making the species highly endangered.
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Ptisana purpurascens
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добавил wikipedia VI
Ptisana purpurascens là một loài dương xỉ trong họ Marattiaceae. Loài này được de Vriese Murdock mô tả khoa học đầu tiên năm 2008.[2]
Chú thích
Liên kết ngoài
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Ptisana purpurascens: Brief Summary
(
виетнамски
)
добавил wikipedia VI
Ptisana purpurascens là một loài dương xỉ trong họ Marattiaceae. Loài này được de Vriese Murdock mô tả khoa học đầu tiên năm 2008.
- лиценца
- cc-by-sa-3.0
- авторски права
- Wikipedia tác giả và biên tập viên
