Examining lichens up close reveals a fascinating world

They go by names like smooth blue jellyskin, scaly dog-pelt, bumpy rim, bloody-cored beard, frosty saucer and yellow- glow wart.

They are lichens, some of Earth’s most amazing organisms. Chances are good that you have numerous lichen species growing in your yard. They grow on just about any surface — rocks, tree bark, soil, wooden fences, tombstones, sidewalks.

A single tree trunk may harbor dozens of different lichens of all shapes and colors. Lichens cover most of Stone Mountain, giving the huge granite monolith a light green patina.

But despite their ubiquity and diversity, lichens get little respect. Most people regard them as mere splotches on rocks and trees and pay them little heed.

However, if you examine lichens under a hand lens, or loupe, a whole new world opens up — as several of us Georgia Botanical Society members discovered last weekend during a “lichen ID” walk in Sweetwater State Park in Douglas County.

Peering at lichens through our 10-power lenses, we could see microscopic landscapes of mountains, valleys, meadows and canyons, bathed in vibrant hues and textures. Lichen fruiting bodies resembled tiny plates, cups and saucers — like those of the pixies cup lichen that was growing on the forest floor. One could imagine wood fairies sipping dewdrops from the little cups.

Leading us were two top lichen experts — Malcolm Hodges, an ecologist with the Nature Conservancy of Georgia, and Sean Beeching.

Perhaps the main reason lichens are so fascinating, Hodges said, is that they all have one important feature in common — they are “composite” organisms made up of at least two components: a fungus and an alga. The algae contain chlorophyll and make food through photosynthesis, contributing the nourishment; the fungi furnish water and minerals and shade.

In these intimate relationships, lichens live, function and reproduce as single organisms. Thus, they are accorded proper Latin names as if they were individual species. For instance, the common lichen known as the sidewalk firedot, which has an affinity for street concrete, is named Caloplaca feracissima.

More than 800 lichen species grow in Georgia, Hodges said. In general, if the substance on a rock or tree trunk is crusty or paperlike, it’s probably lichen. Lichens don’t harm trees but simply find the bark a nice place to live.

IN THE SKY: The moon will be full on Monday — the Bony Moon, as the Cherokee peoples called February's full moon, said David Dundee, Tellus Science Center astronomer. Mercury is low in the west just after sunset. Venus is low in the east just before sunrise. Jupiter is high in the east just after dark. Saturn rises out of the east just before midnight.

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