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A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of
vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 ...
s (plants with
xylem Xylem is one of the two types of transport tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North Ame ...

xylem
and
phloem Phloem (, ) is the living tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North America * ''Triphosa ...

phloem
) that reproduce via
spore )'', growing on a thinning, thinned hybrid black poplar ''(populus, Populus x canadensis)''. The last stage of the moss#Life cycle, moss lifecycle is shown, where the sporophytes are visible before dispersion of their spores: the calyptra (1) is ...
s and have neither
seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released to generally positi ...

seed
s nor
flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plan ...

flower
s. They differ from
moss Mosses are small, non-vascular flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plant ...

moss
es and other
bryophyte Bryophytes are an informal group consisting of three divisions Division or divider may refer to: Mathematics *Division (mathematics) Division is one of the four basic operations of arithmetic, the ways that numbers are combined to make new n ...

bryophyte
s by being vascular, i.e., having specialized tissues that conduct water and nutrients and in having life cycles in which the branched
sporophyte A sporophyte () is the diploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Sets of chr ...
is the dominant phase. Ferns have complex
leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together form the shoot system. Leaves are ...

leaves
called
megaphyll In plant anatomy Plant anatomy or phytotomy is the general term for the study of the internal structure of plants. Originally it included plant morphology, the description of the physical form and external structure of plants, but since the mid ...
s, that are more complex than the
microphyll In plant anatomy and evolution Evolution is change in the Heredity, heritable Phenotypic trait, characteristics of biological populations over successive generations. These characteristics are the Gene expression, expressions of genes that ar ...
s of
clubmosses Lycopodiopsida is a class of herbaceous vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ' ...
. Most ferns are
leptosporangiate fern The Polypodiidae, commonly called leptosporangiate ferns, formerly Leptosporangiatae, are one of four subclasses of ferns, and the largest of these, being the largest group of living ferns, including some 11,000 species worldwide. The group has ...
s. They produce coiled fiddleheads that uncoil and expand into
frond Image:Fern frond lobed.jpg, 300px, A fern (''Dryopteris decipiens'') with simple (lobed or pinnatifid) blades, the dissection of each blade not quite reaching to the rachis. A frond is a large, divided leaf. In both common usage and botanical no ...

frond
s. The group includes about 10,560 known extant species. Ferns are defined here in the broad sense, being all of the
Polypodiopsida A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia art ...
, comprising both the leptosporangiate ( Polypodiidae) and eusporangiate ferns, the latter group including
horsetail ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family (biology), family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus o ...

horsetail
s,
whisk ferns ''Psilotum'' is a genus 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 seed A seed is an embryonic plant encl ...
,
marattioid fern Marattiaceae is the only family of extant (living) fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , ...
s, and
ophioglossoid fern Ophioglossaceae, the adder's-tongue family, is a small family 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 seed ...
s. Ferns first appear in the fossil record about 360 million years ago in the late
Devonian The Devonian ( ) is a geologic period and system of the Paleozoic The Paleozoic (or Palaeozoic) Era ( ; from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the H ...
period, but many of the current families and species did not appear until roughly 145 million years ago in the early
Cretaceous The Cretaceous ( ) is a geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These periods form elements of a hierarchy of division ...

Cretaceous
, after flowering plants came to dominate many environments. The fern ''
Osmunda claytoniana ''Claytosmunda'' is a genus of fern. It has only one species, ''Claytosmunda claytoniana'' (Synonym (taxonomy), synonym ''Osmunda claytoniana''), the interrupted fern, native to East Asia, Eastern Asia, Eastern United States, and Eastern Canada. ...
'' is a paramount example of
evolutionary stasis
evolutionary stasis
; paleontological evidence indicates it has remained unchanged, even at the level of fossilized nuclei and chromosomes, for at least 180 million years. Ferns are not of major economic importance, but some are used for food, medicine, as
biofertilizer '' A biofertilizer (also bio-fertilizer) is a substance which contains living micro-organisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply ...
, as ornamental plants and for remediating contaminated soil. They have been the subject of research for their ability to remove some chemical pollutants from the atmosphere. Some fern species, such as
bracken Bracken (''Pteridium'') is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxon ...
(''Pteridium aquilinum'') and water fern (''
Azolla filiculoides ''Azolla filiculoides'' (water fern) is a species of ''Azolla ''Azolla'' (mosquito fern, duckweed fern, fairy moss, water fern) is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classific ...
'') are significant weeds worldwide. Some fern genera, such as ''
Azolla ''Azolla'' (mosquito fern, duckweed fern, fairy moss, water fern) is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of ...

Azolla
'', can fix nitrogen and make a significant input to the nitrogen nutrition of rice paddies. They also play certain roles in folklore.


Description

Like the sporophytes of seed plants, those of ferns consist of stems, leaves and roots. Ferns differ from seed plants in reproducing by spores. However they also differ from spore-producing
bryophyte Bryophytes are an informal group consisting of three divisions Division or divider may refer to: Mathematics *Division (mathematics) Division is one of the four basic operations of arithmetic, the ways that numbers are combined to make new n ...

bryophyte
s in that, like seed plants, they are Polysporangiophytes, their sporophytes branching and producing many sporangia. Also unlike bryophytes, fern sporophytes are free-living and only briefly dependent on the maternal
gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all ...
.
Stems
Stems
: Fern stems are often referred to as
rhizome In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the A ...

rhizome
s, even though they grow underground only in some of the species. Epiphytic species and many of the terrestrial ones have above-ground creeping
stolon In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechanisms ...
s (e.g.,
Polypodiaceae Polypodiaceae is a Family (biology), family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family includes around 65 genus, genera and an estimated 1,650 species and is placed in the order Polypodiales, suborder ...
), and many groups have above-ground erect semi-woody trunks (e.g.,
Cyatheaceae The Cyatheaceae are a Family (biology), family of tree ferns, the scaly tree ferns, one of eight families in the order Cyatheales in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family may defined much more ...

Cyatheaceae
). These can reach up to tall in a few species (e.g., '' Cyathea brownii'' on
Norfolk Island Norfolk Island (, ; Norfuk language, Norfuk: ''Norf'k Ailen'') is an States and territories of Australia, external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia, directly east of Australia's Evans ...
and ''
Cyathea medullaris ''Sphaeropteris medullaris'', Synonym (taxonomy), synonym ''Cyathea medullaris'', commonly known as mamaku or black tree fern, is a large tree fern up to 20 m tall. It is distributed across the south-west Pacific from Fiji to Pitcairn Islands, Pi ...

Cyathea medullaris
'' in
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
).
Leaf A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together form the shoot system. Leaves are ...

Leaf
: The
green Green is the color between blue and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

green
,
photosynthetic Photosynthesis is a process used by plants and other organisms to convert Conversion or convert may refer to: Arts, entertainment, and media * Conversion (Doctor Who audio), "Conversion" (''Doctor Who'' audio), an episode of the audio drama ' ...

photosynthetic
part of the plant is technically a
megaphyll In plant anatomy Plant anatomy or phytotomy is the general term for the study of the internal structure of plants. Originally it included plant morphology, the description of the physical form and external structure of plants, but since the mid ...
and in ferns, it is often referred to as a ''
frond Image:Fern frond lobed.jpg, 300px, A fern (''Dryopteris decipiens'') with simple (lobed or pinnatifid) blades, the dissection of each blade not quite reaching to the rachis. A frond is a large, divided leaf. In both common usage and botanical no ...

frond
''. New leaves typically expand by the unrolling of a tight spiral called a crozier or
fiddlehead File:Fiddlehead Saint John.JPG, Fiddlehead sculpture at the Saint John Arts Centre by sculptor Jim Boyd in Saint John, New Brunswick, Canada Fiddleheads or fiddlehead greens are the furled fronds of a young fern, harvested for use as a vegetabl ...
into
frond Image:Fern frond lobed.jpg, 300px, A fern (''Dryopteris decipiens'') with simple (lobed or pinnatifid) blades, the dissection of each blade not quite reaching to the rachis. A frond is a large, divided leaf. In both common usage and botanical no ...

frond
s. This uncurling of the leaf is termed
circinate vernation Vernation (from ''vernal'' meaning ''spring'', since that is when leaves spring forth in temperate regions) is the formation of new leaf, leaves or fronds. In plant anatomy, it is the arrangement of leaves in a bud. In pine species, new leaves are ...

circinate vernation
. Leaves are divided into two types a trophophyll and a sporophyll. A trophophyll frond is a vegetative leaf analogous to the typical green leaves of seed plants that does not produce spores, instead only producing sugars by photosynthesis. A
sporophyll A sporophyll is a leaf A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves and stem together form the shoot. Leaves ar ...
frond is a fertile leaf that produces spores borne in
sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. All plants, fungus, fungi, and many other lineages for ...
that are usually clustered to form sori. In most ferns, fertile leaves are morphologically very similar to the sterile ones, and they photosynthesize in the same way. In some groups, the fertile leaves are much narrower than the sterile leaves, and may even have no green tissue at all (e.g., Blechnaceae, Lomariopsidaceae). The anatomy of fern leaves can either be simple or highly divided. In tree ferns, the main stalk that connects the leaf to the stem (known as the stipe), often has multiple leaflets. The leafy structures that grow from the stipe are known as pinnae and are often again divided into smaller pinnules.
Root In vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large grou ...

Root
s: The underground non-photosynthetic structures that take up water and nutrients from
soil Soil is a mixture In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, comp ...

soil
. They are always
fibrous Fiber or fibre (from la, fibra, links=no) is a #Natural fibers, natural or #Man-made fibers, man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest enginee ...
and structurally are very similar to the roots of seed plants. Like all other vascular plants, the diploid sporophyte is the dominant phase or generation in the life cycle. The gametophytes of ferns, however, are very different from those of seed plants. They are free-living and resemble
liverworts The Marchantiophyta () are a division of non-vascular plant, non-vascular embryophyte, land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plan ...

liverworts
, whereas those of seed plants develop within the spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte typically consists of: *
Prothallus '' seen under a light microscope. A prothallus, or prothallium, (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around ...
: A green, photosynthetic structure that is one cell thick, usually heart or kidney shaped, 3–10 mm long and 2–8 mm broad. The prothallus produces gametes by means of: **
Antheridia An antheridium is a haploid structure or organ producing and containing male gametes (called ''antherozoids'' or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. Androecium is also th ...

Antheridia
: Small spherical structures that produce
flagellate 's '' Artforms of Nature'', 1904 (''Giardia lamblia'') ('' Chlamydomonas'') A flagellate is a cell or organism with one or more whip-like Appendage, appendages called flagellum, flagella. The word ''flagellate'' also describes a particular const ...
sperm. **
Archegonia Image:Archegonium.jpg, 240px, Diagram of archegonium anatomy An archegonium (pl: archegonia), from the ancient Greek ''ἀρχή'' ("beginning") and ''γόνος'' ("offspring"), is a multicellular structure or organ of the gametophyte phase of cert ...

Archegonia
: A flask-shaped structure that produces a single egg at the bottom, reached by the sperm by swimming down the neck. *
Rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophyte Bryophytes are an informal group consisting of three divisions Division or divider may refer to: Mathematics *Division (mathematics) Division is one of th ...
s:
root In vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large grou ...

root
-like structures (not true roots) that consist of single greatly elongated cells, that absorb water and mineral
salts In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...

salts
over the whole structure. Rhizoids anchor the prothallus to the soil.


Taxonomy

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement Ennoblement is the conferring of nobility—the induction of an individual into the noble social class, class. Currently only a few kingdoms still grant nob ...

Carl Linnaeus
(1753) originally recognized 15 genera of ferns and fern allies, classifying them in class Cryptogamia in two groups, Filices (e.g. ''
Polypodium ''Polypodium'' is a genus 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 seed A seed is an embryonic plant en ...
'') and
Musci Mosses are small, non-vascular flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plant ...
(mosses). By 1806 this had increased to 38 genera, and has progressively increased since (''see Figure 1''). Ferns were traditionally classified in the
class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently f ...
Filices, and later in a
Division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical division Military *Division (military), a formation typically consisting o ...
of the Plant Kingdom named
Pteridophyta A pteridophyte is a vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), f ...

Pteridophyta
or Filicophyta. Pteridophyta is no longer recognised as a valid
taxon In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechani ...
because it is
paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and all descendants of that ancestor excluding a few—typically only one or two—Monophyly, monophyletic subgroups. The group is said to be paraphyleti ...

paraphyletic
. The ferns are also referred to as Polypodiophyta or, when treated as a subdivision of
Tracheophyta Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 a ...

Tracheophyta
(vascular plants), Polypodiopsida, although this name sometimes only refers to leptosporangiate ferns. Traditionally, all of the spore producing
vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 ...
s were informally denominated the
pteridophyte A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as "cryptogams", meaning that their means of reproduction is hidden. Ferns, h ...
s, rendering the term synonymous with ferns and
fern allies '', from the Equisetopsida (horsetails) Image:Psilotum.jpg, ''Psilotum nudum'', from the Psilotopsida (whisk ferns) Fern allies are a diverse group of seedless vascular plants that are not true ferns. Like ferns, a fern ally disperses by shedding ...
. This can be confusing because members of the division Pteridophyta were also denominated pteridophytes (''sensu stricto''). Traditionally, three discrete groups have been denominated ferns: two groups of eusporangiate ferns, the families
Ophioglossaceae Ophioglossaceae, the adder's-tongue family, is a small family of ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is the only family in the order Ophioglossales, which together with the Psilotales is placed in the subc ...
( adder's tongues,
moonwort ''Botrychium'' is a genus 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 seed A seed is an embryonic plant en ...
s, and grape ferns) and
Marattiaceae Marattiaceae is the only family of extant (living) fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , ...
; and the leptosporangiate ferns. The Marattiaceae are a primitive group of tropical ferns with large, fleshy rhizomes and are now thought to be a sibling taxon to the leptosporangiate ferns. Several other groups of species were considered fern allies: the
clubmoss Lycopodiopsida is a class of herbaceous vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are called clubmosses, firmosses and quillworts. They have dichotomously branching stems be ...
es,
spikemoss thumbnail, 180px, Wallace's Selaginella (''Selaginella wallacei'') ''Selaginella'' is the sole genus of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from the Greek ''trācheia ...

spikemoss
es, and quillworts in
Lycopodiophyta The lycophytes, when broadly circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertex (geometry), vertices of the polygon. The center of this circle is called the circumcen ...

Lycopodiophyta
; the whisk ferns of
Psilotaceae Psilotaceae is a family 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 seed A seed is an embryonic plant enclo ...
; and the horsetails of
Equisetaceae Equisetaceae, sometimes called the horsetail family, is the only extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinctio ...
. Since this grouping is
polyphyletic 300px, Cladogram of the primates, showing a monophyly (the simians, in yellow), a paraphyly">monophyly.html" ;"title="primates, showing a monophyly">primates, showing a monophyly (the simians, in yellow), a paraphyly (the prosimians, in cyan, inc ...
, the term fern allies should be abandoned, except in a historical context. More recent genetic studies demonstrated that the Lycopodiophyta are more distantly related to other
vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 ...
s, having radiated evolutionarily at the base of the vascular plant
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyly, monophyletic – that is, composed of a common ancestor and all its lineage (evolution), lineal descendants - on a phylogenetic tree. R ...

clade
, while both the whisk ferns and horsetails are as closely related to leptosporangiate ferns as the
ophioglossoid fern Ophioglossaceae, the adder's-tongue family, is a small family 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 seed ...
s and
Marattiaceae Marattiaceae is the only family of extant (living) fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , ...
. In fact, the whisk ferns and ophioglossoid ferns are demonstrably a
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyly, monophyletic – that is, composed of a common ancestor and all its lineage (evolution), lineal descendants - on a phylogenetic tree. R ...

clade
, and the
horsetail ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family (biology), family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus o ...

horsetail
s and
Marattiaceae Marattiaceae is the only family of extant (living) fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , ...
are arguably another clade.


Molecular phylogenetics

Smith et al. (2006) carried out the first higher-level pteridophyte classification published in the
molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominately in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
era, and considered the ferns as monilophytes, as follows: *
Division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical division Military *Division (military), a formation typically consisting o ...
Tracheophyta Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 a ...

Tracheophyta
(tracheophytes) - vascular plants ** Sub division Euphyllophytina (euphyllophytes) *** Infradivision Moniliformopses (monilophytes) *** Infradivision
Spermatophyta The spermatophytes, also known as phanerogams (taxon Phanerogamae) or phaenogams (taxon Phaenogamae), comprise those plant Plants are mainly multicellular organisms, predominantly photosynthetic Photosynthesis is a process used by plan ...

Spermatophyta
- seed plants, ~260,000 species ** Subdivision
Lycopodiophyta The lycophytes, when broadly circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertex (geometry), vertices of the polygon. The center of this circle is called the circumcen ...

Lycopodiophyta
(lycophytes) - less than 1% of extant vascular plants Molecular data, which remain poorly constrained for many parts of the plants' phylogeny, have been supplemented by morphological observations supporting the inclusion of Equisetaceae in the ferns, notably relating to the construction of their sperm and peculiarities of their roots. However, there remained differences of opinion about the placement of the genus ''
Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study ...

Equisetum
'' (see
Equisetopsida Equisetidae is one of the four class (biology), subclasses of fern, Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with ...

Equisetopsida
for further discussion). One possible solution was to denominate only the leptosporangiate ferns as "true ferns" while denominating the other three groups as fern allies. In practice, numerous classification schemes have been proposed for ferns and fern allies, and there has been little consensus among them. The leptosporangiate ferns are sometimes called "true ferns". This group includes most plants familiarly known as ferns. Modern research supports older ideas based on morphology that the Osmundaceae diverged early in the evolutionary history of the leptosporangiate ferns; in certain ways this family is intermediate between the eusporangiate ferns and the leptosporangiate ferns. Rai and Graham (2010) broadly supported the primary groups, but queried their relationships, concluding that "at present perhaps the best that can be said about all relationships among the major lineages of monilophytes in current studies is that we do not understand them very well"., p. 1450 Grewe et al. (2013) confirmed the inclusion of horsetails within ferns ''sensu lato'', but also suggested that uncertainties remained in their precise placement. Other classifications have raised Ophioglossales to the rank of a fifth class, separating the whisk ferns and ophioglossoid ferns. One problem with the classification of ferns is that of
cryptic species In biology, a species complex is a group of closely related organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies the Life#Biology, properties ...
. A cryptic species is a species that is morphologically similar to another species, but differs genetically in ways that prevent fertile interbreeding. A good example of this is the currently designated species '' Asplenium trichomanes'' (maidenhair spleenwort). This is actually a species complex that includes distinct diploid and tetraploid races. There are minor but unclear morphological differences between the two groups, which prefer distinctly differing habitats. In many cases such as this, the species complexes have been separated into separate species, thus raising the total number of species of ferns. Possibly many more cryptic species are yet to be discovered and designated.


Phylogeny

The ferns are related to other higher order taxa, as shown in the following cladogram:


Nomenclature and subdivision

The classification of Smith et al. (2006) treated ferns as four classes: *
Equisetopsida Equisetidae is one of the four class (biology), subclasses of fern, Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with ...
(Sphenopsida) 1 order,
Equisetales Equisetales is an order of subclass Equisetidae with only one living family, Equisetaceae, containing the genus ''Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus Genus (plural genera) is a taxonomi ...
(
Horsetail ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family (biology), family of vascular plants that reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus o ...

Horsetail
s) ~ 15 species *
Psilotopsida Ophioglossidae is one of the four class (biology), subclasses of fern, Polypodiopsida (ferns). This subclass consists of the ferns commonly known as whisk ferns, grape ferns, adder's-tongues and moonworts. It is equivalent to the class Psilotopsid ...
2 orders (
whisk ferns ''Psilotum'' is a genus 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 seed A seed is an embryonic plant encl ...
and
ophioglossoid fern Ophioglossaceae, the adder's-tongue family, is a small family 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 seed ...
s) ~92 species *
Marattiopsida Marattiaceae is the only family of extant (living) 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. They d ...
1 order,
Marattiales Marattiaceae is the only family of extant (living) 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 seed A seed is an ...
~ 150 species *
Polypodiopsida A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia art ...
(Filicopsida) 7 orders (
leptosporangiate fern The Polypodiidae, commonly called leptosporangiate ferns, formerly Leptosporangiatae, are one of four subclasses of ferns, and the largest of these, being the largest group of living ferns, including some 11,000 species worldwide. The group has ...
s) ~ 9,000 species In addition they defined 11 orders and 37 families. That system was a consensus of a number of studies, and was further refined. The phylogenetic relationships are shown in the following
cladogram A cladogram (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appr ...

cladogram
(to the level of orders). This division into four major clades was then confirmed using
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology) In archaeology, morphology is the study of the shape of Artifact (archaeology), artefacts and ecofacts. Morphology is a major consid ...

morphology
alone. Subsequently,
Chase Chase may refer to: Business * Chase Bank, a national bank based in New York City, New York * Chase Aircraft (1943–1954), a defunct American aircraft manufacturing company * Chase Coaches, a defunct bus operator in England * Chase Corporation (1 ...
and Reveal considered both lycopods and ferns as subclasses of a class Equisetopsida (
Embryophyta The Embryophyta (), or land plants, are the most familiar group of green plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy into ...
) encompassing all land plants. This is referred to as
Equisetopsida Equisetidae is one of the four class (biology), subclasses of fern, Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with ...
''
sensu lato ''Sensu'' is a Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman ...
'' to distinguish it from the narrower use to refer to horsetails alone,
Equisetopsida Equisetidae is one of the four class (biology), subclasses of fern, Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with ...

Equisetopsida
''sensu stricto''. They placed the lycopods into subclass Lycopodiidae and the ferns, keeping the term monilophytes, into five subclasses, Equisetidae, Ophioglossidae, Psilotidae, Marattiidae and Polypodiidae, by dividing Smith's Psilotopsida into its two orders and elevating them to subclass (Ophioglossidae and Psilotidae). Christenhusz et al. (2011) followed this use of subclasses but recombined Smith's Psilotopsida as Ophioglossidae, giving four subclasses of ferns again. Christenhusz and Mark Chase, Chase (2014) developed a new classification of ferns and lycopods. They used the term Polypodiophyta for the ferns, subdivided like Smith et al. into four groups (shown with equivalents in the Smith system), with 21 families, approximately 212 genera and 10,535 species; * Equisetidae (=Equisetopsida) - monotypic (Equisetales,
Equisetaceae Equisetaceae, sometimes called the horsetail family, is the only extant Extant is the opposite of the word extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinctio ...
, ''
Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study ...

Equisetum
'') horsetails ~ 20 species) * Ophioglossidae (=Psilotopsida) - 2 monotypic orders ~ 92 species * Marattiidae (=Marattiopsida) - 1 monotypic order (Marattiales,
Marattiaceae Marattiaceae is the only family of extant (living) fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , ...
, 2 subfamilies) ~ 130 species * Polypodiidae (=Polypodiopsida) - 7 orders This was a considerable reduction in the number of families from the 37 in the system of Smith et al., since the approach was more that of lumping rather than splitting. For instance a number of families were reduced to subfamilies. Subsequently, a consensus group was formed, the Pteridophyte Phylogeny Group (PPG), analogous to the Angiosperm Phylogeny Group, publishing their first complete classification in November 2016. They recognise ferns as a class, the Polypodiopsida, with four subclasses as described by Christenhusz and Chase, and which are phylogenetically related as in this cladogram: In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the Polypodiopsida consist of four subclasses, 11 orders, 48 families, 319 genera, and an estimated 10,578 species. Thus Polypodiopsida in the broad sense (''sensu lato'') as used by the PPG (Polypodiopsida ''sensu'' PPG I) needs to be distinguished from the narrower usage (''sensu stricto'') of Smith et al. (Polypodiopsida ''sensu'' Smith et al.) Classification of ferns remains unresolved and controversial with competing viewpoints (splitting vs lumping) between the systems of the PPG on the one hand and Christenhusz and Chase on the other, respectively. In 2018, Christenhusz and Chase explicitly argued against recognizing as many genera as PPG I.


Evolution and biogeography

Fern-like taxa (''Wattieza'') first appear in the fossil record in the middle
Devonian The Devonian ( ) is a geologic period and system of the Paleozoic The Paleozoic (or Palaeozoic) Era ( ; from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the H ...
period, ca. 390 Mya (unit), Mya. By the Triassic, the first evidence of ferns related to several modern families appeared. The great fern radiation occurred in the late
Cretaceous The Cretaceous ( ) is a geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These periods form elements of a hierarchy of division ...

Cretaceous
, when many modern families of ferns first appeared. Ferns evolved to cope with low-light conditions present under the canopy of angiosperms. Remarkably, the fern photoreceptor neochrome was obtained via horizontal gene transfer from a
bryophyte Bryophytes are an informal group consisting of three divisions Division or divider may refer to: Mathematics *Division (mathematics) Division is one of the four basic operations of arithmetic, the ways that numbers are combined to make new n ...

bryophyte
lineage.


Distribution and habitat

Ferns are widespread in their distribution, with the greatest richness in the tropics, and least in arctic areas. The greatest diversity occurs in tropical rainforests. New Zealand, for which the fern is a symbol, has about 230 species, distributed throughout the country.


Ecology

Fern species live in a wide variety of habitats, from remote mountain elevations, to dry desert rock faces, bodies of water or open fields. Ferns in general may be thought of as largely being specialists in marginal habitats, often succeeding in places where various environmental factors limit the success of flowering plants. Some ferns are among the world's most serious weed species, including the
bracken Bracken (''Pteridium'') is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxon ...
fern growing in the Scottish highlands, or the mosquito fern (''
Azolla ''Azolla'' (mosquito fern, duckweed fern, fairy moss, water fern) is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of ...

Azolla
'') growing in tropical lakes, both species forming large aggressively spreading colonies. There are four particular types of habitats that ferns are found in: moist, shady forests; crevices in rock faces, especially when sheltered from the full sun; acid wetlands including bogs and swamps; and tropical trees, where many species are epiphytes (something like a quarter to a third of all fern species). Especially the epiphytic ferns have turned out to be hosts of a huge diversity of invertebrates. It is assumed that bird's-nest ferns alone contain up to half the invertebrate biomass within a hectare of rainforest canopy. Many ferns depend on associations with mycorrhizal fungi. Many ferns grow only within specific pH ranges; for instance, the climbing fern (''Lygodium palmatum'') of eastern North America will grow only in moist, intensely acid soils, while the bulblet bladder fern (''Cystopteris bulbifera''), with an overlapping range, is found only on limestone. The spores are rich in lipids, protein and calories, so some vertebrates eat these. The European woodmouse (''Apodemus sylvaticus'') has been found to eat the spores of ''Culcita macrocarpa'', and the bullfinch (''Pyrrhula murina'') and the New Zealand lesser short-tailed bat (''Mystacina tuberculata'') also eat fern spores.


Life cycle

Ferns are
vascular plant Vascular plants (from Latin ''vasculum'': duct), also known as Tracheophyta (the tracheophytes , from Greek τραχεῖα ἀρτηρία ''trācheia artēria'' 'windpipe' + φυτά ''phutá'' 'plants'), form a large group of plants ( 300,000 ...
s differing from lycophytes by having true
leaves A leaf (plural leaves) is the principal lateral appendage of the vascular plant plant stem, stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together form the shoot system. Leaves are ...

leaves
(megaphylls), which are often pinnate. They differ from spermatophyte, seed plants (gymnosperms and angiosperms) in reproducing by means of spores and they lack
flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plan ...

flower
s and
seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released to generally positi ...

seed
s. Like all embryophyte, land plants, they have a biological life cycle, life cycle referred to as alternation of generations, characterized by alternating diploid sporophyte, sporophytic and haploid gametophyte, gametophytic phases. The diploid sporophyte has 2''n'' paired chromosomes, where ''n'' varies from species to species. The haploid gametophyte has ''n'' unpaired chromosomes, i.e. half the number of the sporophyte. The gametophyte of ferns is a free-living organism, whereas the gametophyte of the gymnosperms and angiosperms is dependent on the sporophyte. The life cycle of a typical fern proceeds as follows: # A diploid sporophyte phase produces haploid
spore )'', growing on a thinning, thinned hybrid black poplar ''(populus, Populus x canadensis)''. The last stage of the moss#Life cycle, moss lifecycle is shown, where the sporophytes are visible before dispersion of their spores: the calyptra (1) is ...
s by meiosis (a process of cell division which reduces the number of chromosomes by a half). # A spore grows into a free-living haploid gametophyte by mitosis (a process of cell division which maintains the number of chromosomes). The gametophyte typically consists of a photosynthetic prothallus. # The gametophyte produces gametes (often both sperm and Ovum, eggs on the same prothallus) by mitosis. # A mobile,
flagellate 's '' Artforms of Nature'', 1904 (''Giardia lamblia'') ('' Chlamydomonas'') A flagellate is a cell or organism with one or more whip-like Appendage, appendages called flagellum, flagella. The word ''flagellate'' also describes a particular const ...
sperm fertilizes an egg that remains attached to the prothallus. # The fertilized egg is now a diploid zygote and grows by mitosis into a diploid sporophyte (the typical fern plant).


Uses

Ferns are not as important economically as seed plants, but have considerable importance in some societies. Some ferns are used for food, including the fiddleheads of ''Pteridium aquilinum'' (
bracken Bracken (''Pteridium'') is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxon ...
), ''Matteuccia struthiopteris'' (ostrich fern), and ''Osmundastrum cinnamomeum'' (cinnamon fern). ''Diplazium esculentum'' is also used in the tropics (for example in ''budu pakis'', a traditional dish of Brunei) as food. Tubers from the "para", ''Ptisana salicina'' (king fern) are a traditional food in
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
and the Oceania, South Pacific. Fern tubers were used for food 30,000 years ago in Europe. Fern tubers were used by the Guanches to make gofio in the Canary Islands. Ferns are generally not known to be poisonous to humans. Licorice fern
rhizome In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the A ...

rhizome
s were chewed by the natives of the Pacific Northwest for their flavor. Ferns of the genus ''Azolla'', commonly known as water fern or mosquito ferns are very small, floating plants that do not resemble ferns. The mosquito ferns are used as a biological fertilizer in the rice paddies of southeast Asia, taking advantage of their ability to fix nitrogen from the air into compounds that can then be used by other plants. Ferns have proved resistant to phytophagous insects. The gene that express the protein Tma12 in an edible fern, ''Tectaria macrodonta'', has been transferred to cotton plants, which became resistant to whitefly infestations. Many ferns are grown in horticulture as landscape plants, for foliage, cut foliage and as houseplants, especially the Boston fern (''Nephrolepis exaltata'') and other members of the genus ''Nephrolepis''. The Asplenium nidus, bird's nest fern (''Asplenium nidus'') is also popular, as are the staghorn ferns (genus ''Platycerium''). Perennial (also known as hardy) ferns planted in gardens in the northern hemisphere also have a considerable following. Several ferns, such as bracken and ''Azolla'' species are noxious weeds or invasive species. Further examples include Japanese climbing fern (''Lygodium japonicum''), sensitive fern (''Onoclea sensibilis'') and Giant water fern (''Salvinia molesta''), one of the world's worst aquatic weeds. The important fossil fuel coal consists of the remains of primitive plants, including ferns. Ferns have been studied and found to be useful in the removal of heavy metals, especially arsenic, from the soil. Other ferns with some economic significance include: * ''Dryopteris filix-mas'' (male fern), used as a vermifuge, and formerly in the US Pharmacopeia; also, this fern accidentally sprouting in a bottle resulted in Nathaniel Bagshaw Ward's 1829 invention of the terrarium or Wardian case * ''Rumohra adiantiformis'' (floral fern), extensively used in the floristry, florist trade * ''Microsorum pteropus'' (Java fern), one of the most popular freshwater List of freshwater aquarium plant species, aquarium plants. * ''Osmunda regalis'' (royal fern) and ''Osmunda cinnamomea'' (cinnamon fern), the root fiber being used horticulturally; the fiddleheads of ''O. cinnamomea'' are also used as a cooked vegetable * ''Matteuccia struthiopteris'' (ostrich fern), the fiddleheads used as a cooked vegetable in North America * ''Pteridium aquilinum'' and ''Pteridium esculentum'' (bracken), the fiddleheads used as a cooked vegetable in Japan and are believed to be responsible for the high rate of stomach cancer in Japan. It is also one of the world's most important agricultural weeds, especially in the British highlands, and often poisons cattle and horses. * ''Diplazium esculentum'' (vegetable fern), a source of food for some societies * ''Pteris vittata'' (brake fern), used to absorb arsenic from the soil * ''Polypodium glycyrrhiza'' (licorice fern), roots chewed for their pleasant flavor * Tree ferns, used as building material in some tropical areas * ''Cyathea cooperi'' (Australian tree fern), an important invasive species in Hawaii * ''Ceratopteris richardii'', a model plant for teaching and research, often called C-fern


Culture


Pteridologist

The study of ferns and other pteridophytes is called pteridology. A pteridologist is a specialist in the study of pteridophytes in a broader sense that includes the more distantly related lycophytes.


Pteridomania

Pteridomania is a term for the Victorian era Fads and trends, craze of fern collecting and fern motifs in decorative art including pottery, glass, metals, textiles, wood, printing, printed paper, and sculpture "appearing on everything from infant baptism, christening presents to gravestones and memorials." The fashion for growing ferns indoors led to the development of the Wardian case, a glazed cabinet that would exclude air pollutants and maintain the necessary humidity. The dried form of ferns was also used in other arts, being used as a stencil or directly inked for use in a design. The botanical work, ''The Ferns of Great Britain and Ireland'', is a notable example of this type of nature printing. The process, patented by the artist and publisher Henry Bradbury, impressed a specimen on to a soft lead plate. The first publication to demonstrate this was Alois Auer's ''The Discovery of the Nature Printing-Process''. Fern bars were popular in America in the 1970s and 80s.


Folklore

Ferns figure in folklore, for example in legends about mythical flowers or seeds. In Slavic folklore, ferns are believed to bloom once a year, during the Ivan Kupala Day, Ivan Kupala night. Although alleged to be exceedingly difficult to find, anyone who sees a fern flower is thought to be guaranteed to be happy and rich for the rest of their life. Similarly, Finland, Finnish tradition holds that one who finds the
seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was released to generally positi ...

seed
of a fern in bloom on Midsummer night will, by possession of it, be guided and be able to travel invisibly to the locations where eternally blazing Will o' the wisps called aarnivalkea mark the spot of hidden treasure. These spots are protected by a spell that prevents anyone but the fern-seed holder from ever knowing their locations. In the US, ferns are thought to have magical properties such as a dried fern can be thrown into hot coals of a fire to exorcise evil spirits, or smoke from a burning fern is thought to drive away snakes and such creatures.


New Zealand


Organisms confused with ferns


Misnomers

Several non-fern plants (and even animals) are called ferns and are sometimes confused with ferns. These include: * Asparagus fern—This may apply to one of several species of the monocotyledon, monocot genus ''Asparagus (genus), Asparagus'', which are flowering plants. * Sweetfern—A flowering shrub of the genus ''Comptonia (plant), Comptonia''. * Air fern—A group of animals called hydrozoan that are distantly related to jellyfish and corals. They are harvested, dried, dyed green, and then sold as a plant that can live on air. While it may look like a fern, it is merely the skeleton of this Colony (biology), colonial animal. * Fern bush—''Chamaebatiaria, Chamaebatiaria millefolium''—a rose family shrub with fern-like leaves. * Fern tree—''Jacaranda mimosifolia''—an ornamental tree of the order Lamiales. * Fern leaf tree—''Filicium decipiens''—an ornamental tree of the order Sapindales.


Fern-like flowering plants

Some flowering plants such as Arecaceae, palms and members of the Apiaceae, carrot family have pinnate leaves that somewhat resemble fern fronds. However, these plants have fully developed seeds contained in fruits, rather than the microscopic spores of ferns.


Gallery

File:Silver-fern.jpg, Silver fern or ''Alsophila dealbata,'' endemic to
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
File:Polypodiopsida Fern 01.jpg, Polypodiopsida Fern File:Polypodiopsida Fern 02.jpg, Polypodiopsida Fern File:Adiantum lunulatum W IMG 2336.jpg, ''Adiantum lunulatum'' File:Fern.jpg, Fern leaf, probably ''Blechnum nudum'' File:Tree Fern.jpg, A tree fern unrolling a new frond File:Fern02.jpg, Tree fern, probably ''Dicksonia antarctica'' File:Ferns.jpg, Tree ferns, probably ''Dicksonia antarctica'' File:Haeckel Filicinae 92.jpg, "Filicinae" from Ernst Haeckel's ''Kunstformen der Natur'', 1904 File:Oaxaca fern.jpg, Unidentified tree fern in Oaxaca (state), Oaxaca File:Tree Fern Spores.jpg, Tree Fern Spores San Diego, CA File:Fern-leaf-oliv.jpg, Leaf of fern File:Fern leaves.jpg, Unidentified fern with spores showing in Rotorua, New Zealand, NZ. File:CowellFerns.JPG, Ferns in one of many natural Sequoia sempervirens, Coast Redwood undergrowth settings Santa Cruz, CA. File:Asplenium marinum Moore38.png, Nature printing, Nature prints in The Ferns of Great Britain and Ireland used fronds to produce the plates File:Spiraled fern.JPG, A young, newly formed fern frond File:FernBedInForest.jpg, Fern bed under a forest canopy in woods near Franklin, Virginia File:Pyrrosia piloselloides duit-duit.jpg, ''Pyrrosia piloselloides'', Dragon's Scale, in Malaysia File:Samambaia fern.jpg, Fern growing on a wall File:Fern Spores.jpg, Spores of Dryopteris filix-mas File:Kidney Fern New Zealand. (12185571965).jpg, Thrichomanes reniforme, the Kidney Fern


See also

* British Pteridological Society * Chirosia betuleti - Fern gall * Fern spike * Fern sports * Paisley (design) * Pteridophyte * Silver fern flag


Notes


References


Bibliography


Books and theses

* * , ''see also'' Species Plantarum * Lord, Thomas R. (2006). ''Ferns and Fern Allies of Pennsylvania''. Indiana, PA: Pinelands Press
Ferns and Fern Allies of Pennsylvania - Thomas Reeves Lord
* Moran, Robbin C. (2004). ''A Natural History of Ferns''. Portland, OR: Timber Press. . * * *


Journal articles

* * * * * * * * * * * * * * * * * * *


Websites

* * * * * * * A classification of th






L. Watson and M.J. Dallwitz (2004 onwards). The Ferns (Filicopsida) of the British Isles.





"American Fern Society"

"British Pteridological Society"

Images of ferns of Hawaii


External links

* * {{Authority control Ferns, Fern florae, Non-timber forest products Extant Late Devonian first appearances