Mountain lichens. This bright green crustose species of lichen is Rhizocarpon geographicum. The thallus is yellow-green while the underlayer is black,

---

Mountain lichens. This bright green crustose species of lichen is Rhizocarpon geographicum. The thallus is yellow-green while the underlayer is black, showing through as flecks in the thallus & bordering the edge of a colony in the manner of countries on a map. Photographed on a dry-stone wall in the Lake District, Cumbria.

---

Size: 3785px × 4713px
Photo credit: © MARTIN BOND/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: .geographic, botany, crustose, geographicum, lichen, lichens, mutualism, nature, plant, rhizocarpon, sp., symbiosis, symbiotic, type