Greek version
Endemic species Rare-Threatened Fungi Bryophytes-Lichens Herbarium


BRYOPHYTES - LICHENS

bryophytesBryophytes belong to a primitive group of plants. They are usually green, small and among the simpliest land plants (few are aquatic). They produce no flowers or fruits and most of them have no inner vessels for water or nutrient transfer. They reproduce with spores and can also generate new plants from segments of cut stems or leaves.

bryophytesBryophytes have no roots, but they have thin (one-cell thick!) rhizoids, useful for adhesion to substrate and water absorbance. Most species have very little tolerance to drought and are restricted in moist and protected areas. They are often observed on rocks, ground, fallen trunks and on trees, but they prefer cold and wet forests, swamps and riverbanks. However, several other species exist, growing in extreme weather conditions, such as the Arctic Cycle, Antarctic or deserts. They also thrive on sand dunes, where they play an important role in stabilizing the sand.
The number of bryophyte species globally is estimated at 14,000-15,000.

Lichens are another primitive group of organisms. They result from a peculiar symbiosis of two species belonging in separate kingdoms, functioning as one biological unit. This alliance takes place from a fungus and an alga. Algae participating in this formation belong to either blue-algae or green-algae and participating fungi belong to either discomycetes or basidiomycetes. During this symbiosis, the fungus is fed by organic matter produced from alga's green cell, while the alga absorbs inorganic matter from the fungus.

Several lichen categories exist, according to their structure: foliose lichen

•  fruticose

•  foliose

•  crustose

•  squamulose

Lichens are found on rocks, soil, trees or artificial structures, in intact environments. They can live in various ecosystems all-over the world, even in inhospitable deserts, in Arctic and Antarctic territories. They are considered along with bryophytes, pioneer species in certain biotopes, because they are often the first organisms to invade in newly exposed rock or surface. A lichen may absorb some salts from the substrates it grows on, but it generally feeds through photosynthesis performed by the alga cell. This means that tree lichens are not parasites, they just use trees as their home. However, the lichens growing on rocks may excrete chemicals that accelerate rock's corrosion, creating new soil.

Lichens are important in chinese medicine and in modern times are widely used for the production of antibiotics. Also, the essential oils they contain are the basis for producing perfumes and alcoholic drinks. Several are nutritient and some N African tribes smoke a lichen mixture. They are also used in maquettes and rock gardens, and for dye by American Indians. They are most useful though as air pollution indicators, because they are extremely sensitive to high concentrations of air pollutants. They have no defense mechanisms to pollutants as more evolved plants do, thus when they disappear from an area, they inform us for air pollution in that area.
During 1960's, approximately 50 lichen species were identified on Parnitha.

 
   
 
 
 
 

 

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Contact:

  Forest Service of Parnitha
  Thrakomakedonon Ave.    142, Acharnes. GR13601
   Athens, Greece.

Tel.: 0030 210 2434061-3 fax.: 0030 210 2434064

mail: daspar@otenet.gr

 
   
           
         
           

 Design-editing:
  Eirini Aplada, Biologist-M.Sc. Environmental Biology and Terrestrial and Marine Ecosystem Management

mail: iaplada@yahoo.com
©2006