SFI will again offer “Delving into the Lichen Genus Cladonia” with Dr. Daphne Stone on April 11-12, 2017.

By Kathleen Pyle, SFI Program and Marketing Coordinator

“Delving into the Lichen Genus Cladonia” (which we first offered in 2013) initiated me into a fascinating new subject. I’d always known Cladonias existed but had never bothered to look closer. The elfin world of “cup lichens” comes into focus with a simple hand lens or camera zoom. And it’s a most mysterious and enchanting place to visit. Enchanting because of the fairy-size Cladonia scale and shapes, as indicated by some common species names: clad, lipstick lichen, pixie cups, star-tipped reindeer, etc.

Mysterious, because relatively little is know about how Cladonia lichens evolved. New subspecies are still being discovered and described. Identification can sometimes be complicated: chemical and UV light tests may be required to distinguish between species. Lichenologists in our class – a majority of the students – were old hands at administering P and K tests and looking at specimens under UV lights in the SFI garage.

Cladonia lichens are useful, too. We didn’t venture too far into ethnobotany in Dr. Daphne Stone’s class, but the Cladonia subgenus Cladina (reindeer lichens) provides essential food for reindeer herds.

Cladonia even have a unique vocabulary, which Daphne explained. Lichens combine both algal and fungal parts so they multiply asexually like both organisms. Like algae, they spread by broken off squamules that cluster and grow on hospitable soil surfaces.

Here’s where Cladonias take an interesting turn. The leaf-like structures eventually form a stem, or podetium. Podetia topped with some form of cup (narrow, large, shouldered, gaping) usually characterize species within the Cladonia genus – but not always. Cups bear pcymidia or apothecia, the fruiting bodies that produce fungal spores. A Cladonia lichen may have a simple podetium or a more complex branching pattern like a tree. The classic Cladonia shape resembles a golf tee with a cup instead of a flat top.

Ever notice the red-fruiting lichens spreading mats at the base of trees? Those are a Cladonia species (Cladonia cristella) commonly called British soldiers. New Englanders refer to them as Hessian soldiers, according to Daphne, who grew up in Rhode Island. The red fruits are apothecia. Cladonia apothecia may be red, brown or black.

There is a fractal aspect to Cladonia shapes that inspires art and architecture.  Imagine the Cat-in-the-Hat’s stovepipe hat and you’ll recognize a Cladonia form. In fact, Daphne Stone offered literary proof that Dr. Seuss knew of and frequently used Cladonia as an architectural model! Daphne also shared a green ceramic Cladonia sculpture she created. Here is other Cladonia-inspired art.