|
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. |
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