Anemophilia

Male catkins of the Canadian poplar ( Populus × canadensis )

Common ball-grass ( Dactylis glomerata ) with open flowers

Anemophilia or wind flowering (also anemogamy) describes the adaptation of seed plants to pollination by the wind. Wind flowering is the original form of pollination in seed plants. I.a. the pine -like plants are primarily wind-flowered. In many clans , the flowering species , which are primarily animal-pollinated , have developed secondary to wind flowering again.

features

Adaptation to wind pollination includes the following characteristics:

• The flowers are inconspicuous.
• The number of individual flower organs is reduced.
• The flowers are often unisexual ( dikline : monözie , diözie ).
• The inflorescences are often dense and drooping.
• The anthers are on thin filaments ( "Pendelantheren").
• Little or no pollen putty is formed, so the pollen grains are individual.
• The pollen surface is often smooth.
• The stigma has an enlarged surface area to collect the pollen grains.
• There are only a few or one ovule per flower . The probability that more than one grain of pollen will hit the scar is extremely low.
• No nectar is formed, and accordingly no juice marks either

When there is wind flowering, a very high ratio of pollen grains to number of ovules ( P / O value ) is necessary to ensure a sufficient pollination rate. It is around one million in the pine-tree species and around 2.5 million in the common hazel ( Corylus avellana ). The silver birch ( Betula pendula ), however, has a value of 6700, which is in the range of animal-flowering species. The high cost of pollen production is partially offset by the fact that wind-pollinated pollen usually contains significantly less sporopollenin .

The plant families that are wind-flowering include the sweet grasses (Poaceae) and rushes (Juncaceae), each of which has hermaphrodite flowers. The species-rich genus of the sedges ( Carex ) has unisexual flowers. The order of the beech-like (Fagales) with beech family (Fagaceae) and birch family (Betulaceae) is characterized by unisexual, monoeciously distributed flowers, to it belong many native tree and shrub species. Another group with predominantly wind pollination are the elm family (Ulmaceae), hemp family (Cannabaceae) and nettle family (Urticaceae), which were formerly combined as a separate order Urticales , which are monoecious or diocesan .

Even within clans that are otherwise animal-pollinated, there are often individual species or genera that have moved to wind flowering. An example is the genus meadow rue ( Thalictrum ), in which individual species are wind-pollinated, or the small meadow button ( Sanguisorba minor ) and the genus Artemisia and poplars ( Populus ).

Trivia

Ludwig Ganghofer describes the fir blossom in his novel, " Waldrausch ", which has been filmed several times, as rust-colored clouds that fly through the forest in spring.

supporting documents

• Peter Leins: blossom and fruit. Morphology, history of development, phylogeny, function, ecology . E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart 2000, pp. 219, 206-213. ISBN 3-510-65194-4

Web links

Commons : Wind Pollination  - collection of images, videos and audio files

Individual evidence

1. ↑ Botany: Even conifers have a blossom , Mitteldeutsche Zeitung of Feb. 15, 2005
2. ↑ The "Waldrausch" is there on https://www.mein Bezirk.at from April 28, 2018