Lichens are a symbiotic combination of a fungus and an alga or cyanobacterium. They can grow in all climates and environments as long as they have an undisturbed surface, time, and clean air. Lichens do not damage the plants they grow on, but their growth may increase when more sunlight reaches the bark due to plant decline. Different lichen types can indicate varying levels of air pollution tolerance, with bushy lichens only surviving in very clean air.

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3. What are Lichens?
Lichens are unusual creatures. A lichen is not a single
organism the way most other living things are, but rather it
is a combination of two organisms which live together
intimately. Most of the lichen is composed of fungal
filaments, but living among the filaments are algal cells,
usually from a green alga or a cyanobacterium.

4. Where Do Lichens Grow?
Lichens are located on every continent on planet
Earth, including both the Arctic and Antarctic.
They survive in all climates and altitudes. Specific
lichens have their specific requirements, but in general they need three things
undisturbed surfaces, time, and clean air.
Lichens established on stone in the landscape give the garden a mature look.
Discovering a lichen growing on your tree is not a bad thing. In fact, it should
be celebrated by giving you peace of mind knowing that the environment in
your neighbourhood is clean enough to support this amazing dual organism.

5. Do Lichens Damage Plants?
The short answer is no; lichens do not
cause plant damage. The lichen symbiosis
is not damaging bark in any direct ways. It does not rob
bark of significant amounts of moisture. So why do so many
people, including many horticulturists, think lichens damage
plants? This is due to increased sunlight that penetrates to
the bark which favours the algae that are photosynthesizing,
resulting in enhanced growth. The lichens did not cause the
branch decline, but rather, one of the effects of the plant
decline was an increase in lichen growth.

6. Lichens natural indicators of air
pollution:
• Bushy lichens need
really clean air
- Fructicose have shrubby
appearance often branched.

7. • Leafy lichens can survive
a small amount of air
pollution.
- Foliose having a flat, thin,
and usually lobed.

8. • Crusty lichens can survive
in more polluted air.
- Crustose have most likely a
crusty appearance.
• In places where no lichens are growing, it is
often a sign that the air is heavily polluted
with Sulfur dioxide.

10. What kind of Lichens are these?

11. Lichens in Central Luzon State
UniversityLocations:
• RSTC, CLSU
• Side of the Building of
Engineering, CLSU
• Auditorium, CLSU

12. Foliose
Crustose

13. Foliose
Crustose

14. Crustose
Foliose

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