I walked by a certain River Birch in southeast Iowa. Often I like to lay a hand against the trunk of trees who are personal friends. Say hello.
The bark had a spot of chartreuse, a flat wash of color that I hadn’t seen before. It turned out to be Gold Dust lichen. The photo below is what it looked like when I got a sample under the microscope.
From a distance, no color showed. When I got close, I saw the speck of green on the tree’s shady side. It was too featureless to be moss, too bright to be part of the trunk.
A scrap of bark hung loose, where perhaps a buck had scrubbed his antlers, and it came away at a touch.
I took it home and put it under the microscope.
The yellow-green resolved into powder-fine dots. Indeed, this is categorized as a powdery lichen. The dots are not just part of the lichen — they are the whole thing. Powdery lichens lack all the other features that make most lichens look like lichens.
The dot’s the thing
Many lichens produce tiny blobs, called soredia, which contain the fungus and algae that comprise the lichen. One soredium contains only a few cells but can start a new lichen colony, via asexual reproduction. If we could do the same, any speck of skin could grow into a cloned human.
Powdery lichens have nothing but soredia. Powder growing more powder. It’s the simplest style of lichen reproduction.
Where my lichen scrap is now
When a leading expert in lichenology looked at my sample (Dr. James Colbert, of Iowa State University in Ames, Iowa), he identified it as Gold Dust lichen.
He also pointed out that it had been recorded in Iowa only three times. And never where I live, in Jefferson County. I’d discovered a county first!
My sample now resides in the Ada Hayden Herbarium, where Iowa botanical specimens are collected.
Ada Hayden Herbarium
Since 1870, botanists have contributed the plants they’ve discovered to the herbarium. The samples are dried and carefully quarantined long enough to make sure they’re free from insects that might turn history into frass. The Ada Hayden State Herbarium now contains over 660,000 specimens, which provide tangible proof of what lived here in any era since 1870. Scholars and scientists use the collection for research, identification, and botanical history.
So my scrap of bark bearing Chrysothrix candelaris lichen will be preserved as long as the herbarium stands. I am absurdly pleased by this tiny triumph.
You should be pleased. I am so impressed with your dedication to learning.
Wow Diane. You are contributing to science. How interesting to read this—well done.