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Pleopeltis polypodioides | |
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Pleopeltis polypodioides on an oak limb after a brief rain | |
Fronds on the same limb in desiccated state | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | Polypodiophyta |
Class: | Polypodiopsida |
Order: | Polypodiales |
Suborder: | Polypodiineae |
Family: | Polypodiaceae |
Genus: | Pleopeltis |
Species: | P. polypodioides |
Binomial name | |
Pleopeltis polypodioides | |
Varieties [2] | |
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Synonyms [2] | |
Species
P. p. var. knoblochiana
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Pleopeltis polypodioides, common name resurrection fern, is a species of creeping, coarse-textured fern native to the Americas and Africa.
The evergreen fronds of Pleopeltis polypodioides are 25 cm high by 5 cm wide and monomorphic. The leathery, yellow-green pinnae (leaflets) are deeply pinnatifid, oblong to narrowly lanceolate, usually widest near middle, occasionally at or near base. It attaches to the limbs of its host plant with a branching, creeping, slender rhizome, which grows to 2 mm in diameter. The scales are lanceolate, with light brown base and margins, and having a dark central stripe.
The gametophytes (the haploid gamete producers) develop from very small spores that float in the air and are deposited on moist tree branches. These spores are produced in sporangia that develop on the leaves of the fern's sporophyte. The fern can also reproduce by the division of its rhizomes.
On the underside of the blades, the sori (reproductive clusters) are round, discrete, and sunken. Their outline can be seen as raised dimples on the upper surface. They are typically near the outer edge, and occur on all but the lowest pinnae of fertile fronds. Indusia are absent. Sporangia are yellow to brown at maturity. Spores are produced from summer to fall.
Pleopeltis polypodioides resides in the hardwood forests of southeastern United States in areas including Delaware, Maryland, the Carolinas, Virginia, West Virginia, Illinois, Ohio, Alabama, Georgia, Florida, Mississippi, Arkansas, Texas and Oklahoma. This fern can also be found in areas such as subtropical America, parts of southern Africa and other humid or sub-humid climate areas.
This fern is an epiphyte, or air plant, which means it attaches itself to other plants and gets its nutrients from the air and from water and nutrients that collect on the outer surface of bark. The resurrection fern lives on the branches of large trees such as cypresses and can often be seen carpeting the shady areas on limbs of large oak trees repeatedly exposed to rainfall. However, it is known to grow on the surfaces of rocks and dead logs as well. It is often found in the company of other epiphytic plants, such as Spanish moss.
Pleopeltis polypodioides gets its common name "resurrection fern" because it can survive long periods of drought by curling up its fronds and appearing desiccated, grey-brown and dead. However, when just a little water is present, the fern will uncurl and reopen, appearing to "resurrect". It has been estimated that these plants could last 100 years without water and still revive after a single exposure. [3] [4]
The roots have evolved to function as anchors to tree bark. They have been found to be inefficient in absorption. When in clustered groups of ferns on the bark of trees, the increased transpiration of the ferns and bark allows the middle ferns of the cluster to remain open longer than ferns on the outside. The relative humidity of the air and the closing rate of the leaves of the ferns is an inverse relationship. The greater the humidity, the slower the leaves close because of prolonged exposure to moisture in the air. [5]
Pleopeltis polypodioides can severely desiccate and lose almost all of its water. Experiments have shown it can lose up to 97% and remain alive, though more typically, it loses around 76% in dry spells. [6] [ page needed ] For comparison, most other plants would die after losing only 8–12% water. Upon rainfall or even minute exposures to water, they can fully rehydrate and return to a normal state in 24 to 48 hours. [3] [7] Following substantial exposures to moisture, there is an immediate increase in its water content of up to 50% after the first hour and 65–70% after three hours. [7] When it regains moisture, the fern can once again become photosynthetically active, increasing its metabolism and release of organic compounds that provide nutrients for symbiotic bacteria that allow them both to thrive.
At least one study has shown association between P. polypodioides and moss, [8] indicating that this fern may rely on moss for some of its water needs.
Resurrection ferns accumulate sugar in dehydrated cells in order to protect them and stabilize the membranes and proteins in the dry state. By accumulating sugar, the cells can maintain hydrogen bonds between necessary macromolecules needed for their structure. An interesting feature of the resurrection fern is it does not immediately take up water after having been in a desiccated state. Pleopeltis polypodioides has a porous cell structure network that can expand and rearrange to accommodate absorbing three to four times its weight in water after being exposed. [9]
When the fronds "dry", the mesophyll deforms, which causes the lamina to curl and exposes the underside and show the peltate scales. The peltate scales help prevent photooxidation and mechanical damage, as well as assist in quick rehydration. [10] The fern fronds contain canal cells in the center of their surface scales that direct water to the epidermis of the fern leaves, allowing absorption. The ability of the fern fronds to unroll after exposure to desiccation is attributed to the large cells of the upper epidermis along the midrib of the frond that increase in width more than any other epidermal cell, which forces the fronds to uncurl and flatten out. [5]
Pleopeltis polypodioides has adapted to survive desiccation with the ability of its cell walls to deform and reform, without bursting or rupturing. It has been observed that dehydrins may allow the cell walls of the fern fronds and leaves to deform and reform in times of extreme drought followed by water exposure, due to large fluctuations in water content. Dehydrins were found to be expressed only when the fern was drying or in the desiccated state, with the dehydrins located on the outsides of the cells near the cell walls, allowing the leaves and fronds of the ferns to deform and reform accordingly. [11]
Thermoluminescence of the resurrection fern has been tested to observe at what temperatures it occurs and therefore shows what temperatures and amount of desiccation the ferns can tolerate before their chloroplasts lose the energy they have stored for the plant in the form of light emissions. One study found the resurrection fern required high temperatures before thermoluminescence occurred at around 50 °C, whereas other desiccation-tolerant plants showed thermoluminescence at 40 °C. [12] The thermoluminescent activity of the resurrection fern increased as it was exposed to six separate but consecutive flashes of green safelight at its leaves. Because thermoluminescence from the fern fronds was not observed until higher temperatures, this hints that the fern’s chloroplasts may have a mechanism to withhold and store energy for the fern as it desiccates, allowing it to survive higher temperatures and extreme periods of desiccation. [12]
The fern has spores on the bottom of the fronds, contained in sori. Sori can be found aligned in rows on the underside of fertile fronds. They start as yellow, but as they mature, they turn brown and split. [13] The fern sporulates in summer and early fall. Rhizome sections are also viable offspring and can root themselves in new medium.
The ferns are a group of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissues that conduct water and nutrients, and in having life cycles in which the branched sporophyte is the dominant phase.
Marsileaceae is a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because the leaves of the genus Marsilea superficially resemble the leaves of a four-leaf clover. In all, the family contains three genera and 50 to 80 species with most of those belonging to Marsilea.
Platycerium is a genus of about 18 fern species in the polypod family, Polypodiaceae. Ferns in this genus are widely known as staghorn or elkhorn ferns due to their uniquely shaped fronds. This genus is epiphytic and is native to tropical and temperate areas of South America, Africa, Southeast Asia, Australia, and New Guinea.
Onoclea sensibilis, the sensitive fern, also known as the bead fern, is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from its sensitivity to frost, the fronds dying quickly when first touched by it. It is sometimes treated as the only species in Onoclea, but some authors do not consider the genus monotypic.
The Hymenophyllaceae, the filmy ferns and bristle ferns, are a family of two to nine genera and about 650 known species of ferns, with a subcosmopolitan distribution, but generally restricted to very damp places or to locations where they are wetted by spray from waterfalls or springs. Fossil evidence shows that ferns of the family Hymenophyllaceae have existed since at least the Upper Triassic.
Phlebodium aureum is an epiphytic fern native to tropical and subtropical regions of the Americas.
Selaginella lepidophylla, also known as a resurrection plant, is a species of desert plant in the spikemoss family (Selaginellaceae). It is native to the Chihuahuan Desert of the United States and Mexico. S. lepidophylla is renowned for its ability to survive almost complete desiccation. Resurrection plants are vascular rooted plants capable of surviving extreme desiccation, then resuming normal metabolic activity upon rehydration. The plant's hydro-responsive movements are governed by stem moisture content, tissue properties and a graded distribution of lignified cells affecting concentric stem stiffness and spiraling. During dry weather in its native habitat, its stems curl into a tight ball, uncurling only when exposed to moisture.
Pleopeltis is a genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The genus widely distributed in tropical regions of the world, and also north into temperate regions in eastern North America and eastern Asia. Several species are known by the common name scaly polypody and resurrection fern.
Polypodium vulgare, the common polypody, is an evergreen fern of the family Polypodiaceae. The name is derived from Greek poly- ("many") and pous, podos ("foot"). Polypody has traditional uses in cooking for its aroma and sweet taste, and in herbal medicine as a purgative and vermifuge. This species is expansive and highly adapted to many environments.
Poikilohydry is the lack of ability to maintain and/or regulate water content to achieve homeostasis of cells and tissue connected with quick equilibration of cell/tissue water content to that of the environment. The term is derived from Ancient Greek ποικίλος.
Polypodium glycyrrhiza, commonly known as licorice fern, many-footed fern, and sweet root, is a summer deciduous fern native to northwestern North America, where it is found in shaded, damp locations.
Zealandia pustulata is a species of fern native to eastern Australia and New Zealand. It is commonly referred to as 'kangaroo fern' or 'kangaroo paw fern' as its native range includes Australia and the shape of its mature foliage tends to resemble the shape of a kangaroo's foot. It is also referred to as 'hound's tongue', and as kōwaowao and pāraharaha in the Māori language.
Parablechnum wattsii, synonym Blechnum wattsii, is a common terrestrial fern growing in rainforest and open forest. It is often seen near creeks in much of south eastern Australia, including Victoria, Tasmania, South Australia, New South Wales and Queensland. The specific epithet wattsii honours William Walter Watts (1856-1920). Watts was considered an authority on mosses and ferns and has more than 30 species named for him. Common names by which the species may be called are hard water fern - from its stiff leathery fronds, leech fern - as forest workers often encounter leaches while working in clusters of these ferns, hard hill fern - from the fern's habit and habitat, and red cabbage fern - from the bronze-pink colour of the young fronds resembling cooked red cabbage.
Diplazium australe, commonly known as the Austral lady fern, is a small fern occurring in eastern Australia, New Zealand and Norfolk Island. The habitat is moist shaded areas, often occurring in rainforest.
Polystichum vestitum, commonly known as the prickly shield fern or pūnui (Māori), is a hardy, evergreen or semi-evergreen ground fern.
Aglaomorpha is a genus of ferns in the subfamily Drynarioideae of the family Polypodiaceae. The Pteridophyte Phylogeny Group classification of 2016 uses this genus name, while other sources use Drynaria to include Aglaomorpha. Species are commonly known as basket ferns. As circumscribed in PPG I, the genus contains around 50 species.
Lygodium japonicum is a species of fern that is known by the common names vine-like fern and Japanese climbing fern. It is native to eastern Asia, including Taiwan, Japan, Korea, southeastern Asia, and India, and eastern Australia. The fern is present in the southeastern United States and Puerto Rico as an introduced species.
Gleichenia polypodioides (L.) Sm., commonly known as coral fern, kystervaring or ystervaring 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, while showing exceptional resistance to herbicides.
Rhizome brown, 1–2.5 mm. in diam., creeping, with long-spined dark-brown scales up to 0.5 mm. in diam., 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 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. Pinnules linear, up to 7 x 0.75 cm., pinnate, usually glabrous, 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.
Hymenophyllum tunbrigense, the Tunbridge filmy fern or Tunbridge filmy-fern, is a small, fragile perennial leptosporangiate fern which forms large dense colonies of overlapping leaves from creeping rhizomes. The common name derives from the leaves which are very thin, only a single cell thick, and translucent, giving the appearance of a wet film. The evergreen fronds are bipinnatifid, deeply and irregularly dissected, about 3 to 6 cm long, 2 cm across with dark winged stipes. In contrast to the similar H. wilsonii the fronds are more divided, flattened, appressed to the substrate and tend to have a bluish tint.
Polypodium is a genus of ferns in the family Polypodiaceae, subfamily Polypodioideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). The genus is widely distributed throughout the world, with the highest species diversity in the tropics. The name is derived from Ancient Greek poly ("many") + podion, on account of the foot-like appearance of the rhizome and its branches. They are commonly called polypodies or rockcap ferns, but for many species unique vernacular names exist.