Lichen on tree bark

It is appropriate for there to be two spellings (and two pronunciations) for Lichen. That is because there needs to be a fungus and an algae or cyanobacteria for a lichen to exist. Lichen is an organism that acts in a mutual relationship with  algae converting sunlight into vital nutrients and sugar whilst the partner fungus acts as the host to the new organism.  Thus a lichen is a composite organism that arises from living among   multiple fungi species and algae. Lichens have different properties from those of its component organisms.

Fascinating facts about Lichen

• There are  20- 30,000 varieties of lichen with more being discovered every year
• Lichen takes a vital role in the formation of soil.
• Lichen grows on rocks, walls, buildings, trees and other hospitable surfaces.
• With careful study Lichen can help with navigation when walking in the countryside. It predominantly grows on the north side of trees where the wind comes from the west
• Sunshine can colour  lichen in greens, greys, yellows or even reds dependent on variety and conditions.
• Lichen is a source of food for microbes insects and even reindeer. Some varieties are poisonous to humans.

• There are three  distinct types of lichen: foliose, crustose, and fruticose. Foliose  are leaflike in both appearance and structure, crustose have a crusty appearance.
  
• There are leafy lichen that thrive on rocks at he seaside called Xanthoria parietina with many common names like yellow scale, maritime sunburst lichen and shore lichen.
• Lichens of the species Ochrolechia and Umbilicaria can produce dyes of beautiful brilliant purple and red shades extracted by urine  Orcein produces a reddish-brown dye
• Letharia vulpina or Wolf Lichen is a fruitose of fluorescent yellow color making a dye of a bright yellow color.
• The map lichen rhizocarpon geographicum is luminous green on the southern side where it can harvest more light and a black lines of spores with normal green due to less light on the north.

Lichen no a wall

• Lichen do not harm living trees nor take any food from the bark. They do appear on trees that are older or in decline for other reasons
• Lichen are long lived and slow growing