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An archegonium (pl: archegonia), from the
ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the diale ...
''ἀρχή'' ("beginning") and ''γόνος'' ("offspring"), is a multicellular structure or organ of the
gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert ...
phase of certain
plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, convert light energy into chemical energy that, through cellular respiration, can later be released to fuel ...

plant
s, producing and containing the
ovum The egg cell, or ovum (plural ova), is the female reproductive Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduct ...

ovum
or female
gamete A gamete ( /ˈɡæmiːt/; from Ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply ...
. The corresponding male organ is called the
antheridium An antheridium is a haploid Ploidy () is the number of complete sets of chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins cal ...

antheridium
. The archegonium has a long neck canal or venter and a swollen base. Archegonia are typically located on the surface of the plant
thallus Thallus (plural: thalli), 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 Rome, known as Latium. Through the po ...
, although in the
hornwort Hornworts are a group of 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 th ...
s they are embedded.


Bryophytes

In
bryophytes 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 ...

bryophytes
and other
cryptogam '', a fern '', a moss '', a brown alga Image:Hypholoma fasciculare01.jpg, ''Hypholoma fasciculare'', a fungus A cryptogam (scientific name Cryptogamae) is a plant (in the wide sense of the word) that reproduces by spores, without flowers or seeds. ...
s
sperm Sperm is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as ...

sperm
reach the archegonium by swimming in water films, whereas in
Pinophyta Conifers are a group of cone-bearing seed plants The spermatophytes (; ), also known as phanerogams (taxon Phanerogamae) or phaenogams (taxon Phaenogamae), comprise those plant Plants are predominantly photosynthetic eukaryotes of the Kin ...

Pinophyta
and
Angiosperms Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greec ...
the
pollen Pollen is a powdery substance consisting of pollen grains which are microsporophytes of seed plants The spermatophytes (; ), also known as phanerogams (taxon Phanerogamae) or phaenogams (taxon Phaenogamae), comprise those plant Plant ...

pollen
are delivered by wind or animal vectors and the sperm are delivered by means of a
pollen tube A pollen tube is a tubular structure produced by the male 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 (bio ...
. In the
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
''
Physcomitrella patens ''Physcomitrium patens'', (synonym: ''Physcomitrella patens'' ) the spreading earthmoss, is a moss Mosses are small, Non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ). Bryophyta is now the form ...
'',
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 ...
are not embedded but are located on top of the leafy
gametophoreImage:Physcomitrella patens Gametophor.JPG, Single gametophore of ''Physcomitrella patens'' The word gametophore, also known as gametangiophore, is composed of gametangium and "phore" (Greek Φορά, "to be carried"). In moss and fern (Archegoniata) ...
(s. Figure). The Polycomb protein FIE is expressed in the unfertilized
egg cell The egg cell, or ovum (plural ova), is the female reproductive Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduct ...
(right) as the blue colour after GUS staining reveals. Soon after
fertilisation Fertilisation or fertilization (see American and British English spelling differences#-ise.2C -ize .28-isation.2C -ization.29, spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes ...

fertilisation
the FIE gene is inactivated (the blue colour is no longer visible, left) in the young embryo.


Gymnosperms

They are much-reduced and embedded in the megagametophytes of
gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also ...
s. The term is not used for
angiosperm Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ...

angiosperm
s or the gnetophytes ''
Gnetum ''Gnetum'' is a genus of gymnosperm The gymnosperms ( Greek language, lit. revealed seeds) are a group of Spermatophyte, seed-producing plants that includes Pinophyta, conifers, cycads, ''Ginkgo'', and gnetophyta, gnetophytes, forming the cla ...
'' and ''
Welwitschia ''Welwitschia'' is a monotypic taxon, monotypic gymnosperm genus, comprising solely the distinctive ''Welwitschia mirabilis'', Endemism, endemic to the Namib desert within Namibia and Angola. The plant is commonly known simply as welwitschia in En ...

Welwitschia
'' because the megagametophyte is reduced to just a few cells, one of which differentiates into the egg cell. The function of surrounding the gamete is assumed in large part by
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 chromosomes refer to the number of mate ...
cells of the
megasporangium 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 fo ...
(
nucellus In seed plant 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 ...
) inside the
ovule In seed plant 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 ...

ovule
.
Gymnosperms The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also ...
have their archegonium formed after
pollination Pollination is the transfer of pollen Pollen is a powdery substance consisting of pollen grains which are Sporophyte, microsporophytes of spermatophyta, seed plants, which produce male gametes (sperm cells). Pollen grains have a hard coat ...

pollination
inside female
conifer cone A conifer cone (in formal botany, botanical usage: strobilus, plural strobili) is an organ on plants in the division Pinophyta (conifers) that contains the plant sexuality, reproductive structures. The familiar woody cone is the female cone, ...
s (megastrobili).Brooklyn Botanic Garden
/ref>


References

Plant anatomy Gymnosperms
Plant reproduction {{Commons cat, Plant reproduction Plants, reproduction Horticultural techniques Reproduction, .Plant ...
{{botany he:מורפולוגיה של הצמח - מונחים#איברים בצמחים פרימיטיביים