Last week I attended a presentation about lichens by Malcolm Hodges of the Georgia Nature Conservancy and sponsored by the Florida Native Plant Society, Magnolia Chapter.
The Daily Bucket is a place where we post and exchange our observations about the natural happenings we see. Birds, blooms, bugs and more - each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
January 2013
By his own words, Malcolm is a reformed birder and only started studying lichens 7 years ago. He's now one of a few GA experts and already has a species named after him.
The program was Thursday; Saturday we went exploring to the west of Tallahassee at a slope forest along the Ochlockonee River. Here's my notes from the presentation and a few photos.
Lichens are a compound organism - fungus and algae. The scientific name is derived from the fungal partner. It depends on algae for nourishment which itself needs light for photosynthesis. Therefore you find lichens in sunshine or bright light where fungi generally prefer dark and shady. Note - every time Malcolm made a blanket statement like this, he would qualify with "there are exceptions."
Many species can live together on 1 tree limb but they are epiphytes, in that they do not kill the trees they live upon.
Please follow the orange lichen below for more ...
Some are named "moss" (like this reindeer moss) but they are not moss.
Malcolm talked of how in a lab they can split the fungus from the algae and you end up with 2 rather blah colors that when living together were quite colorful. The fungi need the algae but not vice versa. Some lichens have bacteria that fix nitrogen.
Lichens are designed to shed water as they prefer an environment that allows gaseous exchange. That may explain why many are pollution sensitive. There have been studies in Europe using different lichens to monitor pollutions levels as each population would thrive or die based on their tolerance. They are also useful to study the heavy metals they accumulate.
By learning growth patterns, they have been used to date structures, rock outcroppings and such. Gravestones with dates make an accurate key. That made me think of my mom's headstone that now has a lichen growing on it after 8 years.
Reproduction can be sexual (with fungal spores released in search of new algae) or asexual where bits of fungus surround even smaller algae. Again - the reproduction of the lichen is dependent on the fungus finding the proper algae for growth. Note the reproductive hairs on this lichen.
Types
foliose - leafy with upper and lower surface; Perforated Ruffle
fruticose - branched; Bushy Beard
crustose - flat or paint-like; Southern Crimson Dot
leprose - powdery; Blue-gray Dust
squamolose - scaly; Stalkless Soilscale
When I looked up some basic facts in Wiki - 2 more types were listed.
filamentous (hair-like)
gelatinous lichens
Ecology
They need a surface to grow on: rock, bark, soil or sand, dead wood, leaves. Estimate is 5200 species in North America, 7 even up near the Arctic. Ancient forest and undisturbed lands have the highest diversity. Most are adverse to salt-water; some are not. They have specific parasites like other fungi and nematodes that seek them out.
Scientists have established that there have been 7 independent evolutionary paths for lichens. The oldest fossilized record is @ 400 million years and lichens are believed to be the first to colonize land despite a hostile environment. Then Malcolm mentioned how easy it would be to establish colonies on Mars. They tolerate extreme heat and desiccation thru metabolic suspension and simply waiting. "Field studies" have shown them to survive in space.
Our group heading down to the floodplain.
I found this document while looking up things about Malcolm. It’s a key to lichen ID and glossary. One of the other things I learned was how they use chemicals like bleach and ultraviolet lights to determine species. It seems as the methods improve, they discover new species. And here is an article about a study on lichens in SW Florida that Malcolm referred to.
Typical oak tree in these North Florida woods.
Past DK diarys mentioning lichens
polly
British Soldiers lichen Cladonia cristatella is not just one organism, but a fungus and algae living together to form a new organism.
One of the photos above has a lichen that looks like the British Soldiers but it's not.
me
Check out the stool I found. The cap was formed by layers of peat building up in high water, now exposed but still supporting plants, moss and lichens.
desert scientist
the forest floor was covered with tribble-like lichens that crunched under foot
These are very common around here when you find dry sunny spots in the woods.
and polly again
We tightly hug the mile long granite barrier paddling slowly south toward our heading by canoe. The cliff rises higher and more cleanly from the water, already wildly painted with mineral streaks and bright lichens.
This brings to mind a comment by someone at the presentation about pollution changing the growth of lichens and destroying petroglyphs in the southwest.
--- and a non-lichen picture from our hike --
A very big Bald Cypress growing in the floodplain. It's about 8-10' in diameter. The top got blown out of it long ago and it may be hollow so it was skipped over by loggers. This would have been a typical sized tree long ago. That's my walking stick leaning against the trunk.
The photos above are the most common lichens here in the Florida Panhandle. I see them everyday out in my woods - typically on oak tree branches. Then the trunks of most trees are covered too. Very few trees do not have lichens - pine for instance.
So y'all - here's where you jump in and comment upon lichens in your neck of the woods. Thanks for stopping by.
Wait there's more!
From this morning out in my yard and woods.
Bubblegum lichen - as Malcolm called it. Then my friend Leigh said she called it Rouge lichen to which he smiled and said "you can call it that too." Sorry, I wasn't writing down the scientific names like some of the more learned.
On one like this, I think he said the black dots were reproductive.
A couple of the ones we saw were darker and blotchy like this which he said was from a cyanobacteria.
Live oaks don't have a lot of lichens given the deep heavy bark but this Bubblegum found a home. The green may be algae that has not yet been assimilated.
And one more bit - on the invasive-removal workday yesterday at Wolf Creek Trout Lily Preserve in SW GA, our organizer said when they took Malcolm out there the Friday before, he counted over a 100 different lichens. His goal is to count in all 159 Georgia counties.