Montag, 11. April 2011

Plants in Düsseldorf Part 1

Because of the very beautiful spring weather in my home town of Düsseldorf Germany, I decided to go out; making a little walk in my neighbourhood and to look for some plants or flowers. It is very interesting, how many different species you can find by just go out of your front door. Here are some examples.

The first organisms I want to show isn't real plant but a lichen. Lichens are very interesting organisms; they are a symbiosis between a fungus and an alga (most a green alga or a cyanobacterium). Because they cannot compete with higher plants for optimal conditions, lichens evade on extreme places where higher plants are not able to grow.

This Lichen is known as Xanthoria parietina (L.) Th. Fr., a very common lichen, which can found on trees, rocks, walls an even flagstones on the street. The striking feature of this species is its yellow colour, which is a product of the accumulation of nitrogen. So you can find X. parietina on places with a high rate of fertilization. This one was photographed on a tar plate in the garden of my parents; also a very extreme place two grow

The next species is also an lichen, which I found on the same tar plate like X. paritina. It is called Lecanora muralis (Schreb.) Rabenh. also one of the most common lichens of the world. L. muralis can easily recognize by its pale green Thallus with small brown Asocarps in the middle. The Asocarps are the reproductive organs of a lichen, which creates the spores. Lecanora muralis (Schreb.) Rabenh. is very resistant and can be found everywhere, e. g. streets or walls.

But now we will leave the lichens and go over to the Higher Plants. The first object I found on my tour was this interesting piece.

This (sadly unsharp) picture shows a fertile stalk of Equisetum arvense L. The family of the Equisetaceae is very old and its species are the last surrender of the Equisetopsida. During the Carbon and Perm, this plants were part the main vegetation of the forrest in middle Europe.
Today the genus of Equisetum is the last remaining one of this class. Equisetum arvense L. is a very frequent species, which can be found on fields (name) and also on rubble tips. I found this one on a pavement next to a street.

The interesting point is, that Equisetum has two different forms in which it grows. This picture shows a fertile stalk. The fertile stalk is small and brown. On the top it carries a cone (Sporophylls), which contains the spores. After the spores are released (which happens during April), this brown stalk will disappear and make place for a green, sterile stalk, which is responsible for photosynthesis.

So I was there just at the right time to make this picture of a fertile stalk. Maybe I will upload a picture of the sterile one later this year.

Now we come two the first flower. It is Pulmonaria officinalis agg. L.. This species can easily identified by its blue blossom an the white points on its heart-shaped green leafs. The Herb belongs to the family of the Boraginaceae, a family, which is know by its rough leafs.

I found it on a small way between a field an a small private garden, where someone plant it; maybe as medicinal plant. It loves places with many nitrates in the soil, so it makes sense that I found it next to this field.

The next one is know as Clematis vitalba L.; a member of the Ranuculaceae family. It's a liana, so it climbs up walls, trees and so on. It has woody stem an white crown leaves (Petalen). After pollination, the blossom disappear (it is no longer needed) an the stamp transform into long thin threads, which are used by the ripe fruits to split out with the wind (see picture)

The last plant of the day is also a Ranunculaceae. Ranuclus ficaria L. is a small Herb with golden yellow flowers. It can be found in forest, shrubs or meadows, which are moist enough for this species. I found this one on meadow next to the river of Düssel, which gave Düsseldorf its name.

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