that commanded your attention for, at least, a few brief moments.
Different kinds of lichens have adapted to survive in some of the most extreme environments on Earth: arctic tundra, hot dry deserts, rocky coasts, and toxic slag heaps.
It is estimated that 6% of Earth's land surface is covered by lichen.
There are about 20,000 known species of lichens.
Some lichens have lost the ability to reproduce sexually and yet continue to speciate.
Lichens can be seen as being relatively self-contained miniature ecosystems, where the fungi, algae, or cyanobacteria have the potential to engage with other micro-organisms in a functioning system that may evolve as an even more complex composite organism.
Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide. The long life-span and slow and regular growth rate of some lichens can be used to date events.
Lichens can even live inside solid rock, growing between the grains.