lichen

algae ancestral closeup commensalism commensalistic composite crustose cyanobacteria cyanobionts detail epiphytes erythritol foliose fungal fungi fungus glucose growth haustoria holobiont hyphae lichen lichenicolous lichenized lichenometry lineage macrolichen material microlichen morphogenesis mutualism mutualistic natural nature old organism outdoor parasitic parasitism pathogenic photosynthetic poikilohydric rough surface symbiotic upclose