''Gymnocarpium dryopteris'', the western oakfern, common oak fern, oak fern, or northern oak fern, is a

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

fern of the family Cystopteridaceae. It is widespread across much of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

. It has been found in Canada, the United States, Greenland, China, Japan, Korea, Russia, and most of Europe. Flora of North America, ''Gymnocarpium dryopteris'' (Linnaeus) Newman, 1851. Common oak fern, gymnocarpe fougère-du-chêne
/ref> It is a seedless, vascular plant (with

xylem Xylem is one of the two types of transport tissue (biology), tissue in vascular plants, the other being phloem; both of these are part of the vascular bundle. The basic function of the xylem is to transport water upward from the roots to parts o ...

and

phloem Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is ...

) that reproduces via

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s (not seeds or flowers) and have a life cycle with alternating, free-living

sporophyte A sporophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the biological life cycle, life cycles of plants and algae. It is a diploid multicellular organism which produces asexual Spo ...

and

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...

phases.

Description

''Gymnocarpium dryopteris'' has small, delicate fronds up to 40 cm (16 inches) long, with ternately-compound pinnae (leaves). Fronds occur singly. Each petiole grows from one node on a creeping rhizome. Fronds occur singly. On the underside of matured pinnae the naked sori can be found (the Latin generic name ''gymnocarpium'' means "with naked fruit"). The species grows in coniferous woodlands and on shale talus slopes. Despite its common name, ''Gymnocarpium dryopteris'', a forest understory plant, is not found in association with ''

Quercus An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

'' (oak). In cultivation in the UK this plant and the

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

"Plumosum" have gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

Life-cycle

Like most plant species, oak fern alternates generations, where there is a

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

generation in the form of a

(which produces

s), and is followed by a

haploid 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. Here ''sets of chromosomes'' refers to the num ...

generation in the form of a

(which produces

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s). The

sporangia A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...

are found in clusters on the underside of the leaf, called sori. Each sporangium produces multiple sporocytes, with each sporocyte dividing twice, giving rise to four non-sexual spores. Once the spores

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an flowering plant, angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the sp ...

, they form a

prothallus A prothallus, or prothallium, (from Latin ''pro'' = forwards and Greek ''θαλλος'' (''thallos'') = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young ...

, which develops a number of

archegonia An archegonium (: archegonia), from the Ancient Greek ''ἀρχή'' ("beginning") and ''γόνος'' ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamet ...

(ovaries), and antheridia (spermaries). If water is present, the spermatozoids travel from the antheridia to the archegonia and the egg is

fertilized Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or off ...

when the two come into contact. An embryo then grows out of the gametophyte, producing a sporophyte.

Habitat

Oak fern commonly occurs in moist, shady forests, with wet soil and humid conditions. Often found in drainage areas, ditches and north-facing slopes, it thrives in soils that are well-drained and have a ph of 4.5-6.4. Soil texture varies from silty, clay-loams, to sandy gravel. This fern occurs at elevations of along moderately steep slopes with north, east and west aspects. As it is extremely sensitive to ecological changes, the northern oak fern is an important moisture indicator species.Winkel, A., & Wood, L. J. (2022). Population-level drought responses in northern oak fern (Gymnocarpium dryopteris). Botany, 100(9), 753–760. https://doi.org/10.1139/cjb2021-0114

Gallery

File:Gymnocarpium dryopteris 6028.JPG, The leaf of the fern ''Gymnocarpium dryopteris'', showing sori (groups of sporangia). File:Pteridophyte lifecycle.jpg, Life cycle of a pteridophyte. File:Gymnocarpium dryopteris 6035.JPG, ''Gymnocarpium dryopteris'' shown in the middle of the image, surrounded by sword ferns (''Polystichum munitum'').

References

External links

{{Taxonbar, from=Q1301661

dryopteris :''The moth genus ''Dryopteris'' is now considered a junior synonym of ''Oreta. ''Dryopteris'' , commonly called the wood ferns, male ferns (referring in particular to ''Dryopteris filix-mas''), or buckler ferns, is a fern genus in the family Dry ...

Ferns of the Americas Ferns of Asia Ferns of Europe Plants described in 1753 Taxa named by Carl Linnaeus