Lichen Part fungi part algae

1. LICHEN
by Annie Cloutier copyright 2012 Botany
How can a plant be both a fungi and an algae ?

2. Symbiotic Relationships
in lichen there are two components; fungi and algae
• A photosynthetic component • A green algae or a
> the algae cyanobacterium
• 90% 0f lichen have an algae
component
• Each lichen species has its
own unique species of fungi
• Fungi protect the spongy
• A decomposer component thallus from too much
> the fungi sunlight
• The photosynthetic
component provides food
for both organisms

3. Slow growth...very slow
•The maximum
rate of growth for
a lichen is ~1 cm
(centimeter) per
year and as little
as 0.1mm
millimeter

4. 4,500 years old, now that’s a long life time !

5. Side view of lichen

6. How do lichen hold on ?
By anchor strands of hyphae

7. Types of lichen

8. Got drought ?
How about a flood ?
Lichen can survive both
• Lichen can survive with only 2% water content
of their dry weight
• When this happens the thallus acts a a sun
screen to keep the sunlight from drying out the
remaining spongy medulla
• The thallus is composed of gelatinous
substances that allows the lichen the versatility
to survive extreme variations in rain fall and
temperatures

9. NOT a parasite
•Lichen may be
attached to trees
but they are not a
parasite.

10. Sex or no sex ?
• Lichen reproduce primarily by asexual means
….but
• The fungal component reproduce sexually !
• A third of the species, small powdery clusters of
hyphae disperse soredia and algae bits of the lichen’s
thallus, break off and get dispersed by rain or wind.
• Epiphytes, hang from tree branches at great heights
wind swept spores and animals moving through the
areas of lichen transport the spores
• Lichen algae reproduce by mitosis and simple cell
division

11. Lichen Reproduction

12. Images of hyphae, algae and off spring

13. Take a liking to lichen !
• Part green algae - part fungi