|
Lichen Name
|
Description
|
Means of attachment
to stones
|
Dating
|
Crustose
|
Deeply fixed into the rock, making it immovable. They
are basically 2-dimensional. Forms circular colonies,
black rims. Vary in color. |
This uses the fungal thread of the thalluce to attcach
to the rock. The thallace is the part of the lichen made
up of fungi. |
Crustose are used best for dating. They only grow about
1 millimeter or less a year. This means of dating can
only be used if youre positive the lichens were not present
on the stones before the wall was built. |
Foliose
|
Leaf-shaped. Yellow-green, gray, brown, or orange. This
lichen is a 3-dimensional figure. |
Attaches to the rock by rhizines (which are growths on
the bottom of the lichen) |
Foliose is not as good to use for dating because theyre
growth in a year can vary, but it usually grows about
1 centimeter a year. This growth in a year is high for
lichens and foliose is the only lichen that grows this
much in a year. |
Fructicose
|
Stands upright with protruding plant bodies. They have
been described as "shrub-like" or "beard-like"
Have a cup-like shape. These lichens are more commonly
found on trees, not rocks. |
These lichens form from leaf-like stuctures and then grow
little branch-like structures from the leaf. They usually
grow on the shaded part of a rock in the form of dustings.
|
Has a slow growth, therefore can somewhat be used for
dating, but in dating you also have to take inyo account
how long it took for the lichens to actually form. |
