Gleichenia polypodioides

{{Short description|Species of fern}}

{{Speciesbox

| name = Coral fern

| image = Gleichenia polypodioides, varingblaar, Meiringskloof, a.jpg

| image_caption = Pendent, cremnophytic habit on a sheltered sandstone overhang

| genus = Gleichenia

| species = polypodioides

| authority = (L.) Sm.

| synonyms = Onoclea polypodioides L.

}}

Gleichenia polypodioides (L.) Sm., commonly known as coral fern, kystervaring ('kyster' meaning 'coastal' and of possible Scandinavian derivation) or ystervaring (meaning 'iron fern' in Afrikaans) due to its glabrous, brown, wiry stipes. The species is widespread in south- and east tropical Africa, southern Africa and the western Indian Ocean region. It occurs naturally in a broad coastal belt in South Africa, Lesotho, Eswatini, Angola, Malawi, Burundi, Tanzania, Mozambique, Zimbabwe, Mauritius, Réunion, Amsterdam Island and Madagascar, and was first described by Carl Linnaeus in 1771 under the name Onoclea polypodioides. Often forming dense and impenetrable thickets, sometimes over large areas, this rhizomatous perennial is an important pioneer in disturbed areas such as pine plantations. It is often mistakenly seen as an exotic invader rather than as a useful rehabilitation plant, a source of peat and growing medium,[https://archive.today/20130114172108/http://152.111.1.87/argief/berigte/dieburger/1989/09/09/13/16.html "Peat-producing Fern Exploited and Marketed" - Die Burger]{{cite journal|doi=10.1080/00382167.1977.9629453 | volume=101 | title=Fibrous Root Mat ofGleichenia polypodioidesFern: Possible use as a medium for growing plants / Veselrige Wortelmat Van Die VaringGleichenia Polypodioides:Moontlike Gebruik as 'n Medium Om Plante Te Kweek | journal=South African Forestry Journal | year=1977 | pages=39–46| last1=Morze | first1=J. }} while showing exceptional resistance to herbicides.{{cite journal|doi=10.1080/00382167.1979.9630494 | volume=108 | title=Chemical Control ofGleichenia PolypodioidesFern and Bracken | journal=South African Forestry Journal | year=1979 | pages=43–44| last1=Morze | first1=J. }}

{{quote|Rhizome brown, 1–2.5 mm. in diam., creeping, with long-spined dark-brown scales up to 0.5 mm. in diam. (including spines), with fronds spaced 2–20 cm. apart. Stipe castaneous, up to 60 cm. long and up to 1.5 mm. in diam., glabrous or with a few scales similar to those on the rhizome, shallowly sulcate. Frond bifurcate to reniform-lunate in outline, with 1 (rarely 2) level of false dichotomy in each lateral branch system arising from each side of the terminal bud; all branches bearing distant foliar segments. Aborted apical buds up to 1.2 mm. long, clothed in dark-brown lanceolate laciniate scales (sometimes with black spines). Pinnules (foliar segments) linear, up to 7 x 0.75 cm., pinnate, usually glabrous (but sometimes set with brown laciniate scales), divided into sessile rounded entire triangular lobes, 3 x 2 mm., green to glaucous below. Sori partially immersed in the lamina, consisting of 2–4 sporangia, each in a separate but adjoining pit.|E. A. C. L. E. Schelpe - Flora Zambesiaca}}

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| image1 = Gleichenia polypodioides03.jpg

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| caption1 = Fronds covering an earthbank at Bloukrans Pass, South Africa

| image2 = Gleichenia polypodioides00.jpg

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| caption2 = Monospecific stand on exposed ridge near Karatara, South Africa

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The genus is named after the German botanist W.F. von Gleichen,{{Cite web |url=http://fernkloof.com/species.mv?165 |title=Roridula gorgonias - Vlieebos - Flowers in Fernkloof Nature Reserve near Hermanus |access-date=2012-12-13 |archive-url=https://web.archive.org/web/20151018115539/http://fernkloof.com/species.mv?165 |archive-date=2015-10-18 |url-status=dead }} while "polypodioides" denotes a resemblance to Polypodium which also has sori sunk into the frond surface.Southern African Ferns and Fern Allies - JE Burrows (1990) Gleichenia polypodioides is one of 12 species in the genus,[http://www.theplantlist.org/tpl/search?q=Gleichenia The Plant List] and occurs on sheltered rocks and slopes, along stream- and earthbanks, on road embankments and other disturbed areas, in cool regions of high rainfall or frequent mist, on sites enjoying full sun or light shade. In the subtropics it occurs at elevations from 1,220 to 1,870 m,[http://apps.kew.org/efloras/namedetail.do?flora=fz&taxon=7521&nameid=18830 Flora Zambesiaca, Kew] but in South Africa it is present near sea level.