The stamen, stamen or stamen (plural stamina ) is the pollen -producing organ in the flower of angiosperms. It consists of the stamen ( filament) and the anthers ( anther ). The totality of all stamens of a flower is the androecium. Stamens in hermaphrodite flowers are always between perianth and gynoecium.

It is considered as a leaf organ and is the Mikrosporophyllen heterosexual sporer ferns homologous.

Shape and number of stamen of flowers vary in different taxa.

  • 3.1 staminodes
  • 3.2 Nectar leaves
  • 3.3 Further modifications


Filament and anther

The lower part with which the dust is attached to the blade base of the flower, the filament ( filament ). He is usually narrow and filiform. The length is very different.

  • The most common and also original case is that at which the dust thread immediately continues in the anther: basifixe anther.
  • In some cases, the anther extended in the course of development at the base down over the neck of the stamen out: If this is done on the ventral side of the stamen, ie on the side of the flower center, creates a dorsifixe anther. Dorsifix because the filament attaches to the dorsal = back page.
  • If this is done on the dorsal side of the stamen, produces a ventrifixe anther.

Dorsi and ventrifixe anthers are often designed as a movable Schaukelantheren. These are special adaptations to pollinators that do not land on the flower and therefore only touch the anthers, about butterflies and bats.

Components of the anther

The anther itself consists of a central part, the connective, at the side two counters (singular theca, theca also ) sit. Each theca consists of two pollen sacs. Each pollen sac corresponds to a Mikrosporangium. In the pollen sacs of pollen is formed.

The four pollen sacs are arranged in a characteristic for each family type:

  • Introrsen anthers at both the flowers center pointing pollen sacs are closer to each other.
  • Extrorsen anthers at the two pointing to the flowers outside pollen sacs are closer to each other.
  • Latrorsen anthers at the inner and outer pollen sacs are equidistant from each other. This anthers therefore have two planes of symmetry, whereas the first two cases have only one plane of symmetry.

Structure of the anther wall

The anther wall consists of four layers. The epidermis is the outer layer. This is followed by the fibrous layer ( endothecium ), which ensures the opening of the anthers. Third is a transient intermediate layer. The inner layer, the tapetum, has plasma -rich cells. These provide for a from the pollen mother cells with the necessary nutrients and but on the other Pollenkitt and thus contribute to the formation of the pollen grain wall ( sporoderm ) at.


At maturity, the anther (mostly in the longitudinal direction) opens by a cohesion mechanism (different stress ratios at drying the fiber layer and the epidermis). So Dry weather favors the release of pollen. The pollen is eventually transferred by wind, insects, etc. on the scar.



A Staminodium (plural staminodes ) is a reduction by evolutionary become infertile, so sterile stamen. The Staminodium is a kind of vestigial organ of the flower. Upon further reduction of the stamen can also completely missing. So you can the example of Rachenblütler ( Scrophulariaceae ) establish a regression series, which can also be found in standard textbooks ( the latter two genera are, however, new molecular biological studies now counted among the plantain family ):

  • Mullein ( Verbascum ): five stamens
  • Brown Wurzen ( Scrophularia ): four stamens and a Staminodium
  • Foxgloves (Digitalis ): four stamens
  • Speedwell ( Veronica ): two stamens

Nectar leaves

Nectar or honey leaves are dust or petals that have been transformed for the production of nectar and serve to attract insects. You are at the base of the petals and have a more or less cone- like shape. Nectar leaves are typical of buttercup family. In the genus Buttercup ( Ranunculus ) they are formed like a flower and give the petals a greasy shine. At the base of the petals are, which are then referred to as honey leaves, here is the so-called nectar pit with the nectar gland. Sometimes the honey leaves are also only small and inconspicuous hidden between Kron or stamens as in the Trollblume. Also, they are inconspicuous, so without inspection function in which hellebore and monkshood. In columbine and larkspur field the nectar leaves are spurred and serve between the actual petals sitting as attracting apparatus. When Adonis nectar production is secondary reduced.

Further modifications

Frequently occur on modifications of stamens and staminodes that point to a specific pollination mechanism. So in many species of labiate genus Salvia form ( sage) and eutaxioides in the way Hemigenia two of the four stamens of a joint. This is the precise placement of pollen on the body of the pollinator.

In the ginger family just a functional stamen exists, while reformed staminodes assume the function of petals.

From the connectives of the stamens to leaf-like appendages may form. These are often colored vividly and can simulate a corolla. Such Blütenumbildungen are typical for the family of pondweed plants.