WORKING PAPER NUMBER 4

STUDY MATERIAL

CRUSTY LICHENS

THE TIPE: PHYSCIA TENELLA

-are strongly stuck to the substratum from inferior part ;

-they appear under the from of spots with irregular outline and theyr colour varias;

-generally they grow on trees with a smooth bark such as: beechtrees, elm,trees, linclor trees;

MATERIAL /THE INSTRUMENT NEEDED

-magnifying glass,

-microscope,

-anatomical tweezers;

-spatulated needles;

-razer ;

-blades;

-lamella;

-knife;

-clock glass;

-droppors;

-pothassium hydroxide (a wathery solution 4-20%)

-a glass wand with a top

THE PROCEEDINGS

- put the lichen;on lamellas or on the clock glass;

-we add with a dropper a small quantity of potassium hydroxide (KOH)on the bark apotecs or soralis, or on the material that has been collected from walles ;

-we help the solution of potassium hydroxide entre the structure of the material we are studying by using a the glass wand. We will separate the lichen from the bark after by have delimitated one from the other;

- we repeat the some operation with the speciments we have collected from of other trees;

-the lichens found in a natural from with are identic with those take found on the bark of the trees from nepolluted areas , are or less polluted;

-those who have parts which have bean contaminated with sulphur dioxide and the degree of pollution of the air;

-to obtain , observ a reaction which is different in what concerns the intensity we add a small quantity of wather;

-we position the lamellas or the clock glass under the magnifying glass or under microscope;

-after a certain period of time, we may observe changes in the colour , we can also notice changes in the structure of the tallus, the presence of certain spots, that might ranish after a while, the accumulation noxious substances in the tallus, lesions, the degree of humidity and dryness, differences between the some species situated in areas which are more or less polluted, variations of the diameter of the thallus dependind on the quality of the air from the area from where it has been collected.

The specie: PHYSCIA TENELLA
Harwesting area: DURĂU
Altitude : 800 m the 8^th February 2006
The place from where the material has been drawn	The Findings	The Conclusions
The wood on both sides of the road from the resort station	-very common; -unmodified form; -unmodified natural thallus; -normal rhythm of growth; -unmodified basic characteristics; -they are not coverd by polluting substance;	-the air is litlle polluted; (lest then 30μg/m³)

The analysis has been made by next students:

Gănceanu Iulia, Hultoană Oana, Mucenica Bogdan, Andrei Ştefan.