Most likely a cartilage lichen (the leafy chap) with a sheet lichen and bearded lichen growing on a branch
The lichens on Mountainlands look like exquisite little land corals. They come in different colours, shapes and sizes and can be found growing nearly everywhere from soil, rocks, leaves, bark and on each other. Colours range from road paint yellow, burnt orange to white, mint green and subtle greys and browns. Some form crusts, others have lettuce like leaves or complex branches reminiscent of a labyrinth of hashtags.
For 150 years school text books taught that these composite life forms consisted of fungi forming a mutualistic relationship with green alga or blue-green alga (cyanobacterium), where the latter two produce nutrients through photosynthesis and the fungus produces the structure. It turns out they are more remarkable than that. In 2016 a paper published in the journal Science described a new yeast (also a fungus) participant that went undetected in one of the lineages. Further investigations showed that few lichens match the traditional description and more have partnerships with different fungi and amoeba, bacteria and other micro-organisms making them more complex little ecosystems than previously thought. Scientists are still working out what the purposes of all the newly discovered hangers on are.
Some of the lichens growing on rocks on Mountainlands
Lichens cover about 7 percent of the Earth’s surface. Some can be considered to be extremophiles tolerating harsh conditions growing in the hottest and driest deserts while others in some of the coldest conditions on Antarctica. Lichens have developed the ultimate strategy to tolerate drought and can wait out long dry spells in a state of suspended animation. And they can produce chemicals that act like a sunscreen. When water becomes available again, they resume normal metabolism.
Some species grow fast and others slow and some have a long life span. One growing on Baffin Island holds the record of the oldest at 10 000 years with another species from Sweden at around 9 000 years. That means they started their lives at the end of the last Ice Age. Wrap your mind around that!
Coming back to Mountainlands, preserved in 3.2-billion-year-old Moodies Group rocks is some of the earliest evidence of life on Earth visible to the naked eye. The crinkly lines consist of highly compacted organic carbon and most geologists agree these represent fossilized microbial mats, consisting of single-celled microorganisms. Educated guesses point to cyanobacteria because modern photosynthetic cyanobacteria develop similar microbial mats.
As cyanobacteria is one of the partners that make up lichens, the question becomes: when did algae, fungi, yeasts, bacteria and other micro-organisms form their mutualistic beneficial arrangements? No one really knows when lichens first arose on Earth, as fossil records are rare. The earliest unequivocal evidence has been found in 415-million-year-old rocks from the Welsh borderland, between England and Wales.
Looking like little corals. Most likely Ramalina and Cladonia species
International lichenologists estimate that there are probably 3000 species of lichen in South Africa, with only 1766 named so far. In 2020, the North West University reported that two new lichen species were described from Mpumalanga. One, Scoliciosporum fabisporum, was found on the serpentinite rocks in the Barberton area. The serpentinites are, among others, rich in metals such as nickel and chromium, resulting in soils toxic to many plants, except for a minority of plant species adapted to the soils. This was the first discovery of a new lichen species from serpentinite in the area.
One can easily take lichens for granted as they are always somewhere in the background. However, they are widely recognized as bioindicators of environmental quality, especially atmospheric pollution. They are the proverbial canary in a coal mine and are sensitive to pollutants such as air borne heavy metals and can die as a result, as has happened with some species in Europe since the beginning of the Industrial Revolution.
They have had a long relationship with humans and are used as food, in perfume and deodorants, toothpaste, medicine, spice mixes and as dyes. The more one learns about them, the more one admires them. Lichens, we salute you.
