An antheridium is a

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectivel ...

structure or organ producing and containing male

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s (called ''antherozoids'' or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. Androecium is also the collective term for the

stamen The stamen ( plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the fila ...

s of flowering plants. Antheridia are present in the

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 sex ...

phase of

cryptogam A cryptogam (scientific name Cryptogamae) is a plant (in the wide sense of the word) or a plant-like organism that reproduces by spores, without flowers or seeds. The name ''Cryptogamae'' () means "hidden reproduction", referring to the fact ...

s like

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited in s ...

s and ferns. Many

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...

e and some

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

, for example ascomycetes and water moulds, also have antheridia during their

reproductive The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are a ...

stages. In

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσ ...

s and

angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s, the male gametophytes have been reduced to pollen grains and in most of these the antheridia have been reduced to a single generative cell within the pollen grain. During

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, ...

, this generative cell divides and gives rise to sperm cells. The female counterpart to the antheridium in cryptogams is the archegonium, and in flowering plants is the

gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils' ...

. An antheridium typically consists of sterile cells and spermatogenous tissue. The sterile cells may form a central support structure or surround the spermatogenous tissue as a protective jacket. The spermatogenous cells give rise to spermatids via mitotic

cell division Cell division is the process by which a parent cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukaryotes, there are ...

. In some

s, the antheridium is borne on an '' antheridiophore'', a stalk-like structure that carries the antheridium at its apex.

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File:Chara contraria oogon.jpeg,

Oogonium An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in larg ...

(larger) and antheridium (with red centre) of the alga '' Chara'', produced on the stem of a plant File:Hypnum cupressiforme perichaetialblaetter.jpeg, File:Antheridia polytrichum.jpg, "Moss flowers": each shoot has a cluster of antheridia, i.e., an androecium. File:Marchantia polymorpha male.jpg, Sperm of the liverwort '' Marchantia polymorpha'' are produced on the upper surface of antheridiophores. File:Marchantia antheridium mosbo6.jpg, Cross-sectional micrograph of the antheridial head of ''Marchantia'' sp., showing antheridia containing spermatogenous tissue. File:Equisetum Antheridia.jpg, Antheridium (indicated by the red box) of an ''

Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns, which reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass ...

'' sp.

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See also

References

Further reading