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The 'stamen' (plural ''stamina'', from Latin ''stamen'' meaning "thread of the warp") is the male organ of a flower. Each stamen generally has a stalk called the 'filament' (from Latin ''filum'', meaning "thread"), and, on top of the filament, an 'anther' (from Ancient Greek ''anthera'', feminine of ''antheros'' "flowery," from ''anthos'' "flower,") pollen sacs, called ''microsporangia''. The development of the ''microsporangia'' and the contained haploid spores, (called pollen-grains) is closely comparable with that of the microsporangia in gymnosperms or heterosporous ferns. The pollen is set free by the opening (''dehiscence'') of the anther, generally by means of longitudinal slits, but sometimes by pores, as in the heath family (Ericaceae), or by valves, as in the barberry family (Berberidaceae). It is then dropped, or carried by some external agent — wind, water or some member of the animal kingdom — onto the receptive surface of the ''carpel'' of the same or another flower, which is thus pollinated.
Typical flowers have six stamens inside a '''perianth''' (the ''petals'' and ''sepals'' together), arranged in a whorl around the carpel (pistil). But in some species there are many more than six present in a flower (see, for example, the spider tree flower, below). Collectively, the stamens are called an '''androecium''' (from Greek ''andros oikia'': man's house). They are positioned just below the '''gynoecium'''. The anthers are bilocular, i.e. they have two locules. Each locule contains a microsporangium. The tissue between the locules and the cells is called the 'connective'.
In an immature, unopened flower bud, the filaments are still short. Their function is then to transport nutrients to the developing pollen. They start to lengthen once the bud opens. The anther can be attached to the filament in two ways:

★ basifixed : attached at its base to the filament; this gives rise to a 'longitudinal dehiscence' (opening along its length to release pollen)

★ versatile : attached at its center to the filament; pollen is then released through pores ('poricidal dehiscence').

Stamens can be 'connate' (fused or joined in the same whorl):

★ 'monadelphous' : fused into a single, compound structure

★ 'diadelphous' : joined partially into two androecial structures

★ 'synantherous' : only the anthers are connate (such as in the Asteraceae)
Stamens can also be 'adnate' (fused or joined from more than one whorl):

★ 'epipetalous' : adnate to the corolla

★ 'didynamous' : occurring in two pairs of different length

★ 'tetradynamos' : occurring as a set of six filaments with two shorter ones

★ 'exserted' : extending beyond the corolla

★ 'included' : not extending from the corolla.

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Plant sexuality

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Plant sexuality

:''Main article'': Plant sexuality

In the typical flower (that is, the majority of flowering plant species) each flower has both a 'pistil' and 'stamens'. Bisexual plants are named hermaphrodites or perfect flowers.
In some species, however, the flowers are unisexual with only either male or female parts ('monoecious' = on the same plant; 'dioecious' = on different plants). A flower with only male reproductive parts is called 'androecious'. A flower with only female reproductive parts is called 'gynoecious'.
A flower having only functional stamens is called a 'staminate flower'.
An abortive or rudimentary stamen is called a 'staminodium', such as in ''Scrophularia nodosa''.
The pistil and the stamens of orchids are fused into a column. The top part of the column is formed by the anther. This is covered by an 'anther cap'

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