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The stamen (
plural The plural (sometimes abbreviated An abbreviation (from Latin ''brevis'', meaning ''short'') is a shortened form of a word or phrase, by any method. It may consist of a group of letters, or words taken from the full version of the word or ph ...

plural
''stamina'' or ''stamens'') is the
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 made of sporopollenin that protects the ga ...

pollen
-producing
reproductive organ A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction Sexual reproduction is a type of reproduction Reproduction (or procreation or breeding) is the biological process by which new in ...
of a
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
. Collectively the stamens form the androecium., p. 10


Morphology and terminology

A stamen typically consists of a stalk called the filament and an anther which contains ''
microsporangia Microsporangia are sporangia that produce microspores that give rise to male gametophytes when they germinate. Microsporangia occur in all vascular plants that have Heterospory, heterosporic life cycles, such as Spermatophyte, seed plants, Selagin ...
''. Most commonly anthers are two-lobed and are attached to the filament either at the base or in the middle area of the anther. The sterile tissue between the lobes is called the connective, an extension of the filament containing conducting strands. It can be seen as an extension on the dorsal side of the anther. A pollen grain develops from a
microspore Microspores are land plant The Embryophyta (), or land plants, are the most familiar group of green plant Plants are predominantly photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encomp ...
in the microsporangium and contains 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 (biology), kingdom Plantae. Historically, the plant kingdom encompassed all ...
. The stamens in a flower are collectively called the androecium. The androecium can consist of as few as one-half stamen (i.e. a single
locule A locule (plural locules) or loculus (plural loculi) (meaning "little place" in Latin) is a small cavity or compartment within an organ or part of an organism (animal Animals (also called Metazoa) are organisms that form the Animalia ...
) as in '' Canna'' species or as many as 3,482 stamens which have been counted in the
saguaro The saguaro (, ) (''Carnegiea gigantea'') is a tree-like cactus A cactus (plural cacti, cactuses, or less commonly, cactus) is a member of the plant Plants are predominantly photosynthetic Photosynthesis is a process used by p ...

saguaro
(''Carnegiea gigantea''). The androecium in various species of plants forms a great variety of patterns, some of them highly complex. It generally surrounds the
gynoecium Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom, is the reproduction, reproductive structure found in flowering plants (plants of the division Magnoliophyta, ...

gynoecium
and is surrounded by the
perianth A mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower A flower, sometimes known as a bloom or ...
. A few members of the family
Triuridaceae Triuridaceae are a family of tropical and subtropical flowering plant The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embryophyte, land plants, with 64 Order(biology), orders, 416 Family ...
, particularly ''
Lacandonia schismatica ''Lacandonia schismatica'' is a species of plant in the . It is to in the State of in southern . It is known from very few populations and is considered endangered by the researchers who investigate this species.Davidse, G. & al. (eds.) (1994 ...
'', are exceptional in that their gynoecia surround their androecia.


Etymology

* Stamen is the
Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be in relation with") is "an appa ...

Latin
word meaning "thread" (originally thread of the warp, in weaving). * Filament derives from
classical Latin Classical Latin is the form of Latin language Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication used by humans, including speech (spoken language), gestur ...
filum The filum terminale ("terminal thread") is a delicate strand of connective tissue, fibrous tissue, about 20 cm in length, proceeding downward from the apex of the conus medullaris. It is one of the modifications of pia mater. It gives longitud ...
, meaning "thread"Lewis, C.T. & Short, C. (1879). ''A Latin dictionary founded on Andrews' edition of Freund's Latin dictionary.'' Oxford: Clarendon Press. * Anther derives from French anthère,Klein, E. (1971). ''A comprehensive etymological dictionary of the English language. Dealing with the origin of words and their sense development thus illustration the history of civilization and culture.'' Amsterdam: Elsevier Science B.V. from classical Latin anthera, meaning "medicine extracted from the flower"Siebenhaar, F.J. (1850). ''Terminologisches Wörterbuch der medicinischen Wissenschaften.'' (Zweite Auflage). Leipzig: Arnoldische Buchhandlung.Saalfeld, G.A.E.A. (1884). ''Tensaurus Italograecus. Ausführliches historisch-kritisches Wörterbuch der Griechischen Lehn- und Fremdwörter im Lateinischen.'' Wien: Druck und Verlag von Carl Gerold's Sohn, Buchhändler der Kaiserl. Akademie der Wissenschaften. in turn 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 as Greek (, ), refers collectively to the diale ...
ἀνθηρά (), feminine of ἀνθηρός () meaning "flowery",Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press. from
ἄνθος{{wiktionary Antho- is a prefix derived from the Ancient Greek ἄνθος (anthos) meaning “flower”. It is found in words such as : * Anthomania, an obsession with flowers * Anthocyanins, a class of phenolic pigments found in plants * Anthodite ...
() meaning "flower" * Androecium (plural ''androecia'') derives 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 as Greek (, ), refers collectively to the diale ...
ἀνήρ () meaning "man", and οἶκος () meaning "house" or "chamber/room".


Variation in morphology

Depending on the species of plant, some or all of the stamens in a flower may be attached to the petals or to the floral axis. They also may be free-standing or fused to one another in many different ways, including fusion of some but not all stamens. The filaments may be fused and the anthers free, or the filaments free and the anthers fused. Rather than there being two locules, one locule of a stamen may fail to develop, or alternatively the two locules may merge late in development to give a single locule. Extreme cases of stamen fusion occur in some species of '' Cyclanthera'' in the family
Cucurbitaceae The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family (biology), family consisting of about 965 species in around 95 genera, of which the most important to humans are: *''Cucurbita'' – Squash (plant), squash, pumpkin, ...

Cucurbitaceae
and in section ''Cyclanthera'' of genus ''
Phyllanthus ''Phyllanthus'' is the largest genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term ...
'' (family
Euphorbiaceae The Euphorbiaceae, the spurge ''Euphorbia'' is a very large and diverse genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that ...

Euphorbiaceae
) where the stamens form a ring around the gynoecium, with a single locule.


Pollen production

A typical anther contains four microsporangia. The ''microsporangia'' form sacs or pockets (''locules'') in the anther (anther sacs or pollen sacs). The two separate locules on each side of an anther may fuse into a single locule. Each microsporangium is lined with a nutritive tissue layer called the ''tapetum'' and initially contains diploid pollen mother cells. These undergo meiosis to form
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 called histones which, aided by ...
spores. The spores may remain attached to each other in a tetrad or separate after meiosis. Each microspore then divides mitotically to form an immature microgametophyte called a
pollen grain Pollen Tube Diagram 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 ...

pollen grain
. The pollen is eventually released when the anther forms openings ( dehisces). These may consist of longitudinal slits, pores, as in the
heath A heath () is a shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, Herbaceous plant, herbs, and geophytes. Shrubland m ...
family (
Ericaceae The Ericaceae are a family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain the well-being of its members and of soci ...
), or by valves, as in the
barberry ''Berberis'' (), commonly known as barberry, is a large genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such class ...
family (
Berberidaceae The Berberidaceae are a family of 18 genera of flowering plant The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of Embryophyte, land plants, with 64 Order(biology), orders, 416 Family (biolo ...
). In some plants, notably members of
Orchidaceae Orchidaceae ( ), common name, commonly called the orchid family, is a diverse and widespread family (biology), family of flowering plants, with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two lar ...

Orchidaceae
and
Asclepiadoideae According to APG II, the Asclepiadaceae, commonly known as milkweed family, is a former plant Plants are predominantly photosynthetic Photosynthesis is a process used by plants and other organisms to Energy transformation, conver ...
, the pollen remains in masses called pollinia, which are adapted to attach to particular pollinating agents such as birds or insects. More commonly, mature pollen grains separate and are dispensed by wind or water, pollinating insects, birds or other pollination vectors. Pollen of angiosperms must be transported to the
stigma Stigma or plural stigmata, stigmas may refer to: * Social stigma, the disapproval of a person based on physical or behavioral characteristics that distinguish them from others Symbolism * Stigmata, bodily marks or wounds resembling the crucifix ...
, the receptive surface of the ''
carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom, is the reproduction, reproductive structure found in flowering plants (plants of the division Magnoliophyta, ...

carpel
'', of a compatible flower, for successful
pollination Pollination is the transfer of pollen from an anther (male part) of a plant to the stigma (female part) of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by Anemophily, wind. Pollinating agents are a ...

pollination
to occur. After arriving, the pollen grain (an immature microgametophyte) typically completes its development. It may grow a pollen tube and undergoing mitosis to produce two sperm nuclei.


Sexual reproduction in plants

In the typical flower (that is, in the majority of flowering plant species) each flower has both
carpels '' stigmas and style Gynoecium (, from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...

carpels
and stamens. In some species, however, the flowers are unisexual with only carpels or stamens. (
monoecious Monoecy (; adjective form: monoecious ) is a sexual system in seed plants The spermatophytes (; ), also known as phanerogams (taxon Phanerogamae) or phaenogams (taxon Phaenogamae), comprise those plant Plants are predominantly photosynthet ...
= both types of flowers found on the same plant;
dioecious Dioecy (; 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 approximately 10.7 million as o ...
= the two types of flower found only on different plants). A flower with only stamens is called androecious. A flower with only carpels is called gynoecious. A flower having only functional stamens and lacking functional carpels is called a staminate flower, or (inaccurately) male.Encyclopædia Britannica.com
/ref> A plant with only functional
carpel Gynoecium (; ) is most commonly used as a collective term for the parts of a flower A flower, sometimes known as a bloom or blossom, is the reproduction, reproductive structure found in flowering plants (plants of the division Magnoliophyta, ...
s is called
pistillate '' stigmas and style Gynoecium (, from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
, or (inaccurately) female. An abortive or rudimentary stamen is called a staminodium or
staminode In botany, a staminode is an often rudimentary, sterile or abortive stamen, which means that it does not produce pollen.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''; Published by Gerald Duckworth & Co. ...
, such as in '' Scrophularia nodosa''. The
carpels '' stigmas and style Gynoecium (, from Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...

carpels
and stamens of
orchid Orchidaceae ( ), commonly called the orchid family, is a diverse and widespread family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social ...

orchid
s are fused into a
column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression (physical), compression, the weight of the structure above to other structural elements below. In other words, a column is ...
. The top part of the column is formed by the anther, which is covered by an anther cap.


Terminology

;Stamen Stamens can also be adnate (fused or joined from more than one whorl): * epipetalous: adnate to the
corolla Corolla may refer to: *Corolla (botany) upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is ...
* epiphyllous: adnate to undifferentiated
tepal A tepal is one of the outer parts of a flower A flower, sometimes known as a bloom or blossom, is the reproduction, reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological ...
s (as in many
Liliaceae The lily family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject ...

Liliaceae
) They can have different lengths from each other: * didymous: two equal pairs * didynamous: occurring in two pairs, a long pair and a shorter pair * tetradynamous: occurring as a set of six stamens with four long and two shorter ones or respective to the rest of the flower (
perianth A mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower A flower, sometimes known as a bloom or ...
): * exserted: extending beyond the corolla * included: not extending beyond the corolla They may be arranged in one of two different patterns: * spiral; or * whorled: one or more discrete whorls (series) They may be arranged, with respect to the
petals upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) Petals are modified leaves A leaf (plural leaves) is the principal lateral appendage of the ...

petals
: * diplostemonous: in two
whorls A whorl is a type of spiral or circular pattern. Other meanings of whorl include: * Whorl (botany), the attachment of sepals, petals, leaves, or branches at a single point * Whorl (biology), the structure of some organs, used in the aid of ident ...
, the outer alternating with the petals, while the inner is opposite the petals. * haplostemenous: having a single series of stamens, equal in number to the proper number of petals and alternating with them * obdiplostemonous: in two whorls, with twice the number of stamens as petals, the outer opposite the petals, inner opposite the sepals, e.g.
Simaroubaceae The Simaroubaceae are a small, mostly tropical, family in the order Sapindales. In recent decades, it has been subject to much taxonomic debate, with several small families being split off. A molecular phylogeny of the family was published in 200 ...
(''see
diagram A diagram is a symbolic representation Representation may refer to: Law and politics *Representation (politics) Political representation is the activity of making citizens "present" in public policy making processes when political actors act in ...
'') ;Connective Where the connective is very small, or imperceptible, the anther lobes are close together, and the connective is referred to as discrete, e.g. ''
Euphorbia ''Euphorbia'' is a very large and diverse genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV ...

Euphorbia
'' pp., '' Adhatoda zeylanica''. Where the connective separates the anther lobes, it is called divaricate, e.g. ''
Tilia ''Tilia'' is a genus of about 30 species of trees or bushes, native throughout most of the temperateness, temperate Northern Hemisphere. The tree is known as linden for the European species, and basswood for North American species. In Britain and ...
'', ''
Justicia gendarussa Justicia may refer to: * ''Justicia'' (plant), a genus of flowering plants in the family Acanthaceae * ''Justicia'' (album), by Eddie Palmieri, 1969 *Justicia (Madrid), ward in the Madrid city center *SS Justicia, SS ''Justicia'', British ship *A 20 ...

Justicia gendarussa
''. The connective may also be a long and stalk-like, crosswise on the filament, this is a distractile connective, e.g. ''
Salvia ''Salvia'' is the largest genus of plants in the sage family Lamiaceae, with nearly 1000 species of shrubs, herbaceous plant, herbaceous perennial plant, perennials, and annual plant, annuals. Within the Lamiaceae, ''Salvia'' is part of the tri ...

Salvia
''. The connective may also bear appendages, and is called appendiculate, e.g. '' Nerium odorum'' and some other species of
Apocynaceae Apocynaceae (from ''Apocynum ''Apocynum'', commonly known as dogbane or Indian hemp, is a small genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, includi ...
. In ''Nerium'', the appendages are united as a staminal corona. ;Filament A column formed from the fusion of multiple filaments is known as an androphore. Stamens can be connate (fused or joined in the same whorl) as follows: * extrorse: anther
dehiscenceDehiscence can refer to: * Dehiscence (botany), the spontaneous opening at maturity of a plant structure, such as a fruit, anther, or sporangium, to release its contents * Wound dehiscence, a previously closed wound reopening * Superior canal dehisc ...
directed away from the centre of the flower. Cf. introrse, directed inwards, and latrorse towards the side. * monadelphous: fused into a single, compound structure * declinate: curving downwards, then up at the tip (also – declinate-descending) * diadelphous: joined partially into two androecial structures * pentadelphous: joined partially into five androecial structures * synandrous: only the anthers are connate (such as in the
Asteraceae The family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain the well-being of its members and of society. Ideally, fam ...

Asteraceae
). The fused stamens are referred to as a synandrium. ;Anther Anther shapes are variously described by terms such as linear, rounded, sagittate, sinuous, or reniform. The anther can be attached to the filament's connective in two ways: * basifixed: attached at its base to the filament ** pseudobasifixed: a somewhat misnomer configuration where connective tissue extends in a tube around the filament tip * dorsifixed: attached at its center to the filament, usually versatile (able to move)


Gallery


References


Bibliography

* * * *


External links

{{Authority control Plant anatomy
Plant morphology ''Plant morphology'' is the field in botany that studies the diversity in forms, with the naked eye or slight optical magnification. This is opposed to plant anatomy (see :Plant anatomy) that needs to cut into plants to be able to study its subject, ...
Plant sexuality Plant reproductive system Pollination