Saturday, August 20, 2011


Many trees growing lichens. It is doubly strange beings who are made up of fungi and algae. Together they form a symbiosis. To live as a team, they have only light and moisture. In this process, that their very specific appearance may vary with regard to size, color and shape.
Lichen fungi are different from their old age that can reach the fruiting bodies and the existence of a permanently visible plant body, the thallus.
They differ from mosses in the absence of fresh greens and also by the absence of sporangia. Lichens are usually gray, greenish gray, yellowish gray, yellow, orange or brown. They are often crusty plaques or bush-like structures.
crust-like lichen

Survival Artists
Lichens can be very old, even ancient. They grow slowly, but only in places where they do not have to compete with angiosperms. Only moss, Iceland moss and some other species can survive in closed vegetation (grasslands and dwarf shrub vegetation Schale). They are common on rocks and on the bark of trees. Especially in the mountains felt lichen is comfortable. They can dry out completely without suffering harm, and tolerated temperature differences are found in all climate zones. Worldwide there are about 16,000 species
Many lichens are rare or even threatened their existence and should not be cut off for a collection.
Lichens that grow on trees (epiphytic lichens) are most threatened. They suffer changes in their living room. These are bright, natural forests with old trees. These are increasingly rare. Lichens react very sensitively to pollutants like sulfur dioxide, but also on climate change. They are a kind of living for measuring changes in the environment that the person concerned. Research has shown that the disappearance of lichens is associated with respiratory problems in humans.
Growth Forms
There are three main types of fruiting bodies: crust-like, leaf-shaped and bushy.
The crust-like lichens are intertwined with their host.
In the leaf-shaped lichen thallus is more or less divided into lobes. In many places they are connected with the host, sometimes using special adhesive organs. Navel Lichens are only one fixed point.
Among the shrubby lichens, all species grow three-dimensionally in space. They are small shrubs. To this group belong to the lichen beards. Their thallus is like a beard of the branches off trees.
Even clearer is the shrub lichens that are upright. They are often richly branched, sometimes rod-shaped horn or spear. Often they have leaves or scales over the host outgrow.
leaf-shaped lichens
Vegetative propagation
Lichens have bodies, soralia, soredia and isidia, for the vegetative vemeerdering serve. Isidia tend bar or club-shaped to branched coral-like or sometimes nearly globular growths of thallusbovenzijde. They break off easily. Afgebrolen develop to share the new short mosses.
Soralia are visible as a 'mealy', typically whitish-gray to green rash on the thallus. They consist of groups of very small, roughly spherical cells, which are called soredia. They are in the tissue layer of the thallus constructed, where algae live. Their shape is oblong or linear, sometimes even around. There are convex and concave shapes.
On the under side of leaf-shaped lichens are known rhizinen or adhesive fibers. They serve to anchor the thallus to the host. They are branched or brush-shaped and seem on pipe cleaners. Some native foliage and lichens are shrubby edges or tips of the brush covered with thalluslobben uitstekels shaped, cilia or eyelashes to be called.
The cover of the lichen soredia or reproduce isidia are usually no fruiting. Other species are up to fruit set. Fruit bodies with short mosses are formed by the component of the fungal thallus.
shrub shrub lichen lichen

Literature on mosses and lichens
For more information about these lichens to determine I recommend the book "Mosses and Lichens" by Volkmar Wirth / Ruprecht Dull, publisher Tirion.

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