Poineer species of Xerosere Succession, shows resurection, Natural farmers, In Medicine, Perfumes, dyes, Antibiotics, In Biryani, Litmus paper, Tanning, Bioindicators, Biodeterioration, Lichenometry

1. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
Importance of Lichens
Lichens are very important in both ecologically and economically.
Ecological importance:
Lichens are pioneer species, play an important role colonising new surfaces, these are able to
colonize places where there are extremes of humidity, temperature and light, and they often
occur in places where few other macroscopic living things can survive. In xerosere plant
succession, saxicolous lichens are the first living things to grow on bare rock or areas denuded
of life by a disaster. It helps to bind and stabilize soil sand in dunes. In deserts and semiarid
areas, lichens are part of extensive, living biological soil crusts, essential for maintaining the soil
structure. Lichens play an important role in weathering of rocks and soil formation, carryout
weathering of rocks by two means, i.e biogeophysical weathering and biogeochemical
weathering. Lichens helps in soil formation and stabilization. There is a strong relationship
between soil pH and lichen growth. Because of it, many lichens can grow even in desert areas.
Among the desert lichens, some squamulose lichens like Catapyrenium, Heppia, Peltula, Psora
etc. can grow even at 500
c or more for long time. These strongly attach to the soil and help in
stabilization of soil.
In addition to distinct physical mechanisms by which lichens break down raw stone, recent
studies indicate lichens attack stone chemically, entering newly chelated minerals into the
ecology.
Lichens release complex chemical substances into the substratum and these form chemical
complexes with iron, manganesium, calcium, aluminium etc to form metal complexes, and
change the chemical nature of the substrates. These changes help in weathering of the substrate
rocks. In most of the lichens the reserve food material is calcium oxalate and it helps in
weathering of rocks. Due to the effect of lichens basalt, mica, celtussar and other minerals
gradually form soil.
Among the metabolites excreted by some lichens are acids. Acids have the capacity to degrade
the surfaces on which they are located, thus releasing minerals for uptake by the thallus. Acidic
digestion has the effect of causing the slow disintegration of the surface, especially of limestone
and other calcareous materials.
The lichen exudates, which have powerful chelating capacity, the widespread occurrence of
mineral neo formation, particularly metal oxalates, together with the characteristics of weathered
substrates, all confirm the significance of lichens as chemical weathering agents.
Over time, this activity creates new fertile soil from lifeless stone.
Cyanophycophilous lichens provide the bulk of fixed nitrogen, azotodesmic (nitrogen fixing)
Lichens viz. Labaria, Peltigera contribute nitrogen to the ecosystem.
Most crustose lichens growing on rocks dissolve and disintegrate them into soil particles.
Limestone rocks are dissolved by the action of certain chemical secreted by lichens and the
disintegration of rocks is due to stress and strain included by contraction and expression of
gelatinous thalli. When the lichens die and decay, they form humus soil together with rock

2. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
particles, mosses, forms and other plants grow on it. Thus they prepare ground for succession of
vegetation.
Economic Importance of Lichens:
Lichens are very important economically as food, fodder, medicines, in industrial production of
various dyes, drugs, cosmetics, perfumes, tanning, brewing, distilling and also in bio-
deterioration, biodegradation, bio-indicators, lichenometry etc.
Food: Lichens grow luxuriantly at very cold temperatures of Polar Regions. Number of lichens
uses in preparation of different food items. Cetraria islandica “Iceland moss” was used as food
in Northern Europe and was cooked as porridge, soup, bread, salad and pudding. Bryoria
fremoontii were mostly used as food in times of famine in North America so they were called
famine food. In China, lichens are used as food (Lobaria isidiophra, L.yoshimurae) and also as
health promoting tea (Thamnolia subuliformis, Lethariella cashmeriana). Cetraria islandica
commonly known as “Iceland moss” is grounded up and mixed with wheat flour. Leathery lichen
Umbillicaria, commonly known as “root tripe” has been eaten by travellers in arctic regions in
danger of starvation, in Japan use in salad or fried to eat. Cladonia rangifera, commonly known
as “reindeer moss” food for reindeers and cattle. Leconora esculenta and others growing on
rocks and sand dunes in Lybian desert are grazed by goats.
Some of the fodder species of lichen include Cladonia rangiferina, C. alperstris and C. sylvatica
other fodder species include Cetraria islandica, Dermatocarpon miniatum, Stereocaulon and
Alectoria. These lichens contain carbohydrate lichenin as reserve food material in high quantities
and 5-6% proteins. However, due to lichen acids, they taste sour and bitter. Hence, they are used
after cooking or overnight soaking. Parmelia known in Telugu as “rathapu” or rock flower
has been used in curry preparation and is famous for its delicacy. Species mixture of Parmelia,
Heterodermia, Pyxine and Physcia are extensively used to increase the flavour of the Indian
spicy dish 'Biryani' from Kasmir to Kanyakumari.
In Medicine:
Lichens contain several secondary metabolites, which are use as medicine in nature.
The Cetraria islandica “Iceland moss” used in the treatment of many diseases like diarrhea,
jaundice, fevers, epilepsy, hydrophobia etc. it is also used in the preparation of culture media.
The Usnea and Evernia furfuracea is used as astringents. Cladonia pyxidata is used to cure
whooping cough.
Peltigera canina, the dog lichen was used as medicine for hydrophobia in ancient days and
Lobaria pulmonaria, lungwort was used for the diseases of lungs. Xanthoria sp are used in
jaundice.
Sailaja - Permalia parlata relieves headache. Cooling and refrigerant action, useful in dyspepsia
and also in the treatments of snake and scorpion bite and Parmelia saxatilis is used to cure
epilepsy.
Letharia vulpina ("wolf lichen") used it to make poison Arrow heads; it was a Blackfoot remedy
for stomach disorders.
Umbilicaria esculenta found to contain anti-HIV substances.
Parmelia spp. is used in wound healing in parts of Eastern Ghats, India.

3. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
Pharmaceutical products using Usnea spp. as ingredient in Anti-Fungal Remedy, Fitosept,
Fytotherapie, Deodorant Spray, After Shave Herbal Water production.
Usnea barbata (Old man beard) used as remedy for Whooping Cough, catarrh, Epilepsy dropsy,
astringent, anti-cancer, a tonic and a diuretic, hair growth stimulant.
Usnic acid – used in treatment of tuberculosis and skin diseases and Soric acid from lichens like
species of Cetraria, Cladonia and Parmelia is used in cancer treatment.
Erythrin, obtained from Roccella montagnei is used in angina (a cardio vascular disease).
Lichens are also used in the preparation of many antiseptic creams eg. Usno and Evosin.
Some lichens contain protolichesterinic acid, used in preparation of anticancer drugs.
Some lichens are used in control of plant diseases also. Sodium usnate can control tomato
canker disease. Leconoric acid and usnic acid can control tobacco mosaic disease. Water extract
of lichens like Nephroma, Hypogymnea, Platismatia and others can control the growth of wood
rotting fungi.
Traditional medicine
Lichens have been used in traditional medicine practices of many cultures. Historically in
Europe, Lobaria pulmonaria was collected in large quantities as "Lungwort", due to its lung-like
appearance. Similarly Peltigera leucophlebia was used as a supposed cure for thrush, due to the
resemblance of its cephalodia to the appearance of the disease, Umbilicaria used to treat
jaundice.
In Ayurvedic Medicine Parmelia perlata use as - relieves headache, cooling and refrigerant
action, antifungal, antibacterial and anti-inflammatory properties, promotes spermatogenesis.
(Speman, Confido, V-gel).
In Siddha Medicine Parmelia perlata use as febrifuge, Astringent, resolvent, Emollient,
demulcent.
Fresh Lichen collection is doing in Wayanad, by Kerala tribes (Kattunaika), with acceptance of
the State Forest Department, Kerala.
Antibiotic metabolites
Lichens produce metabolites proven useful in the medical treatments. Most metabolites produced
by lichens are structurally and functionally similar to broad spectrum antibiotics while few are
associated respectively to antiseptic similarities. These organic acids are the metabolic by
products of Crassulacean acid metabolism, the means of photosynthesis by lichens. Usnic acid is
the most commonly studied metabolite produced by lichens and has been associated with the
suppression of tuberculosis, Vulpinic acid exhibited mild antibiotic activity, proved as a
bactericidal against Escherichia coli and Staphylococcus aureus and is considered an
antimicrobial agent.
As dyes
Many lichens produce secondary compounds, including pigments that reduce harmful amounts
of sunlight and powerful toxins that reduce herbivores or kill bacteria. These compounds are
very useful for lichen identification, and have had economic importance as dyes such as cudbear
or primitive antibiotics. The dye orchil & cudbear extracted from species of Rosella,
Leconora and others are used for dying the silk and wool garments. Orcinol, the dye used for
chromosomal staining in biology laboratories is prepared from orchil, in the presence of sodium

4. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
or potassium carbonates, form azolitmin and erythrolitmin. The pH indicator (an acidic or base
indicator) in the litmus test is a dye extracted from the lichen Rosella tinctoria , Rosella
montagnei by boiling.
In Perfumes: aromatic biochemical compounds present in lichen thallus are used in preparation
of a number of perfumes. Evernia prunastri (oak moss), Lobaria pulmonaria, Pseudevernia
furfuracea (tree moss), Fursuracia and Ramalinae spp. are mostly used as ingredients in soaps,
cosmetics, after shave lotions and perfume for a peculiar, earthy, mossy fragrance. Some lichens
known as Earth Flowers have a strong and distinct odor so they are smoked along with tobacco
used in summer dances.
Lichenometry is a technique used to determine the age of exposed rock surfaces based on the
size of lichen thalli. Introduced by Beschel in the 1950s, the technique has found many
applications. It is used in archaeology, palaeontology, and geomorphology. It uses the presumed
regular but slow rate of lichen growth to determine the age of exposed rock. Lichenometry is
especially useful for dating surfaces less than 500 years old, as radiocarbon dating techniques are
less accurate over this period. The lichens most commonly used for lichenometry are those of the
genera Rhizocarpon (e.g. the species Rhizocarpon geographicum) and Xanthoria.
Biodegradation: Biodegradation is the chemical dissolution of materials by biological means.
Lichens have been shown to degrade polyester resins, as can be seen in archaeological sites in
the Roman city of Baelo Claudia Spain. Lichens can accumulate several environmental
pollutants such as lead, copper, and radionuclides.
Biodeterioration: The biodeterioration of diverse natural and man-made substrata by Caloplaca
aurantia, Lacanora muralis and Acarospora oxytoma identified. The presence of calcium oxalate
monohydrate and dehydrate in the lichen encrustations is identified for these high-oxalate
producing bio deteriorative lichen systems. The lichens adopt different methods for the
production and removal of the hydrated calcium oxalates in the encrustations. In the geological
context, it use as a biological weathering agents in the development of soils.
Bio-Indicators: Lichens are used as bio indicators of air quality, it grows in pollution free
places, usually do not grow in polluted environments, very sensitive to two chemical pollutions
Ozone (O3) and sulphur dioxide (SO2) in the atmosphere. They are not commonly found in
highly polluted towns and cities due to heavy and rapid industrialization, these areas are
commonly described as “lichen deserts”. As the level of pollution increase, their number
decrease. By this trend, degree of air pollution can be predicated. Lichens are used to detect
pollution due to sulphur dioxide, heavy metals and other pollutants. The level of chemical
pollution due to toxic metals like lead, nickel, zinc, chromium, mercury, fluorine etc. is
detected by lichens. These species can also be used as a means to assess pollution by radioactive
substances that may occur following crash of satilites, uranium mining operations and nuclear
fallout from weapon testing eg. Hypogymnia enteromorpha, Evernia prunastri, Parmelia
saxatilis, Lepraria incana, and species of Cladonia, Usnea.

5. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
Aesthetic appeal: Colonies of lichens may be spectacular in appearance, dominating the surface
of the visual landscape as part of the aesthetic appeal to paying visitors of Yosemite National
Park and Sequoia National Park. Orange and yellow lichens add to the ambience of desert trees,
rock faces, tundras, and rocky seashores. Intricate webs of lichens hanging from tree branches
add a mysterious aspect to forests. Fruticose lichens are used in model railroading and other
modelling hobbies as a material for making miniature trees and shrubs.
Use in Tanning: In France and other Europe countries, the astringent substances extracted from
the thalli of Cetraria islandica and Lobaria pulmonaria have been in use for tanning leathers.
Brewing and distilling: In Russia and Siberia, lichens are used in the brewing of beer. Lobaria
pulmonaria has been used in the brewing of beer. Cladonia rangiferina, Usnea florida and
Ramalina fraxinea have been used in the preparation of alcohol.
Religious purposes: due to their pleasant smell lichens are used in manufacture of dhup and
havan samagries, which are used for performing religious ceremonies.
Harmful effects:
Forest fire: The thalli of Usnea are particularly inflammable, dry thalli of lichens in forest from
the thick mat on tree branches and easily catch fire. So there is high risk of forest fire due to
lichens.
Damaging buildings: Lichens can grow on the walls of buildings. As they secret acids, they can
damage the plasters and shining beauty of buildings.
Lichens of genera Amphiloma and Cladonia cause total destruction to the colonies of masses by
direct parasitic attack. The hold fast hyphae of Usnea often pierce through the cortex to the
inner tissues of the host. It destroys the middle lamella of the cell wall and ultimately enters into
the cells causing total destruction.
Shading of leaf: lichens can grow on the plant leaves and block the sunlight, so that
photosynthesis of plant is badly affected.
Some lichens such as Letharia vulpine- the wolf moss are poisonous. Evernia prunastri cause
skin allergy.

6. Dr.D.Nagaraju, Asst. Prof. Of Botany, Govt. Degree College, Warangal
Fig: Importance of Lichens - outline.
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