The Rhizocarbon Oederi Lichen grows all over the Pacific Northwest. This crustose lichen forms large pale rusty color colonies on rocks near rivers and lakes. Sometimes the patches have darker brown tints in it and when growing in the shade they can take on a greenish color.
The edge is not well defined. The apothecia are rarely larger than 1 mm, their shape range from very slightly concave to very slightly convex and they are quite flat. The wide rims are flat with the disc but are paler and the discs often have a small mound of sterile tissue at their centers.
Found along the coast on both granite and limestone rocks at the edge of small rivers or around lakes. It likes to be rinsed in water occasionally and will always be found at the edge of the water.