Ramalina - Ramalina durieui - Ramalina |
The ramalina are a genus
of lichens with a typical shrubby structure. They are very different from the
lichens we are used to seeing on walls, rocks and stones. At least one species of
ramalina can be found in the Maltese islands. Instead of having the familiar
circular shape, this species, which one finds growing on trees at Buskett and the
nearby valley of Girgenti , has the shape of shredded grey
leaves stuck onto a branch or twig.
The genus ramalina
consists of about 240 species. They are found widely around the world in
various habitats.
In the Maltese islands
about two hundred species have been recorded. Most are coloured patches
decorating stone or wood surfaces. Lichens are very slow growing and it takes a
very long time for a freshly exposed surface to become covered in lichen.
Lichens are usually the
first organisms to colonise bare surfaces. They can survive in inhospitable
environments because they can make the most out of two worlds. A lichen
consists of two organisms, a fungus and a green algae or a cyanobacterium
living together symbiotically.
It was only in 1867 that
the dual nature of lichens was discovered by Simon Schwender, a Swiss professor
of botany who was director of the Botanical Gardens in Basel . His discovery was not immediately accepted
as a number of leading lichenologists did not believe that a species could be
made up of two different organisms.
Some species of lichen
are eaten regularly. While some species are considered a delicacy others are
resorted to only in times of famine. In Northern Europe a lichen was cooked as
a bread, porridge and even eaten as a salad.
Lichens have been used
for centuries to produce dyes especially red and purple. They have also been
used as a source of primitive antibiotics. Some compounds in lichens are useful
as they can reduce harmful rays from the sun.
This article was published in The Times of Malta on February 2014.
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