Likin' Lichen

While I am by no means an expert in regards to lichens, I have definitely dabbled in their realm.  In fact, I plan to dabble more in the future.  A recent email from a friend down Georgia way (check out Fitz Clarke's great Flickr page here) got me thinking about lichens again.

What is a lichen?  Lichens are not a single organism, but a symbiotic relationship between fungi, green algae and/or cyanobacteria (blue-green algae).  I recall learning in school that the fungi part of a lichen provided the "home" to the algae, while the algae provided the "food" via photosynthesis.  Of course, things are not as simple as they appear; the particular fungi/algae relationship differs from one lichen to the next and the relationship isn't always a friendly, two-way street.  Apparently there are upwards of 15,000 different species of fungi (primarily Ascomycetes) that form lichens!  And as for lichens themselves, there are nearly 14,000 distinct species found practically everywhere, and on every kind of surface, in the world.

So, why bother with lichens?  If you ask that question, you obviously have never taken the time to notice them.  I admit, many lichens can be quite inconspicuous and easy to overlook, but once you've noticed them you CAN NEVER UNNOTICE THEM.  Okay, well maybe you can, but I most definitely cannot. 

For example, there is no missing the Christmas Wreath Lichen, aka Bubblegum Lichen (Cryptothecia rubrocincta). 

This particular specimen readily demonstrates why it is sometimes referred to as "Bubblegum Lichen"

This lichen brings back fond memories of growing up in southeastern Georgia, where this splash of pink mottles every oak in site.  There are only two species of Cryptothecia in North America, both restricted to the extreme Southeast.  C. striata isn't as striking, it lacks the red pigment.  C. rubrocincta is also found in South America where it has been used as a source of red dye in Brazil.

As I mentioned earlier, some lichen (okay maybe a lot of lichen) are easy to overlook.  However, if you take a moment to look closely, you may find that they are much more interesting.  Take Script Lichen (Graphis scripta) for an example. 

Another common lichen occurrence on oaks in the Southeast.

From a distance, you may only see a whitish smudge on a branch with some black streaks or dashes.  Look a bit closer and you may begin to see why this particular group of lichens are known as "script" lichens.  There are only 39 species of Script Lichen in North America, most restricted to the Southeast and Florida claims 25 of them.  G. scripta is the most common and widespread across most of Eastern North America. 

How about this sickly looking Lichen?  Bark Rash Lichen (Pyrenula cruenta), one of 48 species of "bark rash" or "pox" lichens found in North America, again this species restricted to the Southeast.  This specimen was a tiny patch I found growing on scrawny, young oak, marsh-side at Skidaway Island State Park.  I think the photo clearly shows where these lichens get their common name.

Pyrenula cruenta, one of the Bark Rash Lichens.  Hey, I even see some Script Lichen!

Well, I don't think I'm doing a good job convincing you that lichen are easy to miss.  Here is another striking species Haematomma accolens, one of the Bloodspot Lichens.  This is an easily recognized group and there are only 7 species in North America, 5 of which are found in the Southeast.  Again, I think the photo will clearly show where the common name comes from.

One of the North American Bloodspot Lichens, Haematomma accolens.

Like I said before, lichens can be found growing on almost any surface.  So far I've shown you examples on tree bark.  Take a look at this attention-grabbing species that grows on rocks. 

I hope you enjoyed looking at this Sidewalk Firedot Lichen (Caloplaca feracissima) before you burned your retinas to ash.

Why the hell did I bother saying that lichens were easy to miss??  There are 133 species of Firedot, or Jewel Lichens in North America.  This particular species is at home growing on natural limestone and even sidewalks.  I photographed this specimen on a huge limestone chunk bordering a parking lot. 

Well, I wish I could tell you about each and every one of the ~14,000 species of lichen in the world.  I think these five interesting species should be plenty to peak your interest in these cool organisms.  And I promise you can easily overlook lichens.  So PAY ATTENTION.  You probably missed out on at least a dozen just today.

Go look at some lichen!

For an amazing reference on Lichens of North America, check out this book.

Also check out, A Guide to the Lichens of Howard County, MD - a great resource online for a lot of commonly encountered species, download it here