Like Download 3.63 MB blue lichen 2316 x 2080 pixels Aspect ratio 579:520 Canon PowerShot SX710 HS 13.921 mm f/4.5 1/50 s ISO 200 Online since: 31 October 2018 Taken: 5 November 2015 CC0 / Public Domain lichen blue gray round symbiosis nature algae fungus