Trouble with Lichen

Green grows the lichen oh.
Lichens are made up of two or more closely interacting organisms, a fungus, and one or more partners, called photobionts.
Lens used The Elmar-C 90mm f/4.0 consists of 4 elements.
Closest focusing distance: 1 m. Weight: 265 gr together with its rubber lens hood.
Length from bayonet flange: 61 mm, screw-in rubber lens hood, folds back on the lens. Filter size: Series 5.5. Leica catalog number 11540. Comes with soft leather case.