- grows like a crust on trees or rocksFoliose - leaf-like (the light green ones in this picture)Fruticose - long, hairy lichens, often with cups Squamulose - Thallus (main body of lichen) is scaly, shelf-like; the reproductive bodies are called podetia Umbilicate - these lichens grow on rocks; they are attached at one point near the center by an "umbilicus" Gelatinous - these lichens are a dark blue-green, black or brown; the thallus is jelly-like; they grow on trees or the ground, often associated with moss
Hmmm, too bad this vein of "gold dust" is just a lichen growing on the white quartz! Real gold is often found in veins of quartz in mines.
This interesting mix of lichen species shows some of the varieties that can be found on a single twig. Often, older tree branches may be completely covered in lichens. The cup-like structures are called apothecia, they contain the spores for the lichen's reproduction. These lichens were photographed on tree bark at Tremont in the Smokies.
Sidewalk firedot lichen; Caloplaca feracissima
? Oak Ridge, TN This is a close-up of the small, yellow crustose lichen that was growing on our driveway. I had to remove it with a power washer because it was making the driveway slick when it was wet.
This tree at the San Antonio, TX Botanical Gardens looked as though it had been painted, but the white marks are actually lichens.
This is an orange lichen I found growing on a headstone in a nearby cemetery.
Pitted Stone Lichen; Verrucaria calciseda
? This lichen looked as though it had been pricked with a pin, the black holes were very tiny. Copy of Liverwort lichen
The upper (right) and lower (left) edges of the thallus, the "body" of the lichen, are visible in this photo. The little black hair-like projections are called cilia, they are often used as aids for identifying lichen species. I received my Lichens of North America book (by Irwin M. Brodo, Sylvia Duran Sharnoff and Stephen Sharnoff), so now I can tentatively identify many of the lichens I find during my travels. The book is a HUGE (~3" thick) reference guide, it is definitely not a field guide that I will carry in my backpack! I'll use the book to try to identify the lichens in this gallery (you'll see the word "possibly" a lot!). Please refer to a professional guide and run the field tests for more accurate identification if you are working on a research paper, as many lichens look alike. I try to be as accurate as possible, but I'm not an expert! :)
Lung Lichen; Lobaria pulmonaria
Great Smoky Mountains NP March 18, 2009 I was excited to find this lichen growing along the Porter's Creek trail. I had learned about it at the Lichen Workshop. This would have been green had it been wet. Note the "vein" texture on the lobes and the small bumpy apothecia on the edges. This lichen is often used as an indicator species for air quality studies since it is highly sensitive to pollutants.
Parmotrema spp. Great Smoky Mountains NP Feb. 21, 2009 These black cilia are growing on the edges of the thallus of this lichen.
I liked the patterns of this lichen and how it changes color as it grows.
The Usnea species of lichens have a central core made up of hyphae strands called the axis; it gives the branches rigidity. This core can be revealed by gently pulling the green cortex and medulla layers off. The axis is an identifying characteristic for this genus.
Cross-section of a Lichen thallus The thallus is the "body" of the lichen. It is made up of fungal hyphae and algal cells. The cortex is a layer of highly compacted fungal cells on the upper surface(and sometimes, lower surface) that protects the algal layer. The algal cells (photobiont) photosynthesize sugars for the lichen. The medulla is a spongy section of the lichen made up of loose fungal hyphae. Not all lichens have a lower cortex (including crustose lichens).
Gold Dust Lichen; Chrysothrix candelaris
Great Smoky Mountains NPFeb. 21, 2009 This brilliant yellow crustose lichen can cover large patches of rock. This is a lichen that can be seen from far away.
I got a kick out of seeing these squiggly marks on the lichen on tree bark. A hungry snail or slug rasped away with its radula (mouthparts) to eat the lichen, leaving these telltale marks behind.
The yellowish crustose lichen in the center of this photo has been infected by a fungus!
A white crust lichen growing on a tree trunk.
This old headstone in an Oak Ridge cemetery was nearly obscured by lichens. It was interesting to see how different types of lichens preferred certain kinds of stone and light conditions. This is a white marble stone, it is located in a partially shaded spot near a red cedar tree.
Another common place to find lichens is on headstones in old cemeteries. I found this one in Cades Cove in the Smokies. These lichens are growing on the sheep, which is made of marble. Some of the very old headstones were nearly illegible due to a heavy growth of lichens.
Candleflame lichen; Lemon Lichen; Candelaria concolor
Oak Ridge, TN Feb. 25, 2009 I found this lichen growing on the dogwood tree in my yard.
Candleflame lichen; Lemon Lichen; Candelaria concolor
(yellow) Great Smoky Mountains Feb. 21, 2009 This pretty little yellow lichen is common on trees in the southeast. I thought it was interesting how this one was growing on another lichen. The olive-green plants nearby are small liverworts.
Christmas Lichen; Cryptothecia rubrocincta
Munson, FL Dec. 26, 2008 I had seen this pretty lichen in a state park near Orlando, FL in 2000; I was surprised by the bright red color. The red hue comes from a chemical called chiodectonic acid. The lichen is used as a dye in Brazil.
After I got back from the Lichen workshop at Tremont, I was anxious to see what our trees had to offer in meiofauna. We had some of our Silver Maple trees trimmed (not topped!) recently, so there was a huge supply of lichens easily available. I soaked them in a jar of water overnight and looked at them the next day. I was surprised to find a Desmid (single-celled alga) in my collection water. Meiofauna are microscopic animals, protozoa, and algae that live in the sediment layer between the lichen and the tree bark. Unfortunately, I didn't find any Water Bears (Tardigrades) in my sample.
(yellow) Teloschistes exilis Bastrop, TX March 26, 2009 When Kenny and I went to Central Texas during Spring Break of 2009, I was amazed at the incredible variety of lichens I saw on the trees and rocks! There were lots of twigs on the ground with mixtures of lichens on them due to a wind storm earlier that morning.
(composite) There is no real foliose lichen that has all of these features, but all of those lichens will have some of them. Lobes can be narrow or wide, they give the lichen its "leafy" appearance (thus the term "foliose"). Cilia are thin appendages that are found on the lobe margins of some lichens. Rhizines are not roots, they are outgrowths of hyphae that attach the lichen to its substrate (rocks, bark, etc.) These structures do not take up water or nutrients like plant roots. Sorelia and Isidia are vegetative reproductive bodies that contain both fungi and algae, they can grow a new lichen if the small pieces end up in a good growing location. Apothecia are flat or cup-like reproductive structures.
Smoky Eye Boulder Lichen; Porpidia albocaerulescens
Great Smoky Mountains NP Feb. 21, 2009 This is a very common crustose lichen that grows on the rocks in the park. It is easy to identify because of the little bluish-gray apothecia, the cup-like reproductive bodies.
Common Button Lichen; Buellia stillingiana
Oak Ridge, TN Feb. 24, 2009 This lichen is very common in the eastern half of the US. I found this one growing on the bark of a tree in my yard. The black apothecia make this lichen easy to identify.
Flame Firedot Lichen; Caloplaca ignea
(orange)PossiblyAcarospora sp. (yellow)March 20, 2007 I found this brightly-colored lichen growing on granite rock in Joshua Tree National Park in southern California.
I found these Crustose and Foliose Lichens growing on the old fiberglass truck bed topper in my parents' yard.
Pale Rockwool; Speerschneidera euploca
Leakey, TX (Lost Maples SP) March 29, 2009 I found this odd lichen growing on a limestone boulder in Lost Maples State Park during our trip to Texas.
Black-foam Lichen; Anzia colpodes
Great Smoky Mountains NP Feb. 21, 2009
Lichen on a tree in the Great Smoky Mountains I've got to work on the ID of this one!
Piney River Trail, Spring City, TN Thanks to the folks at the Lichen workshop I attended at the Tremont Institute in the Smoky Mountains (Feb. 2009), I finally learned what kind of lichen this is! Thanks, Jennifer! I have seen it often while hiking and thought it was unusual, but I never knew what it was. It grows on rocks, often interspersed with moss. Although it looks green it is not a plant, it is a lichen so it is classified in the Kingdom Fungi. The little brown knobs are the reproductive bodies called apothecia.
Diagram of the Cross-section of an Usnea strigosa lichen branch
Sinewed Ramalina; Ramalina americana
Great Smoky Mountains NP Feb. 22, 2009 These flat-branched lichens are commonly found growing on tree bark. Larger specimens have round, flat apothecia on the ends of the branches. The scientific names of some of the lichens are fun to say, like "Ramalina"!
Common Script Lichen; Graphis scripta
Great Smoky Mountains NP Feb. 21, 2009 This is such a cool-looking lichen when seen at higher magnifications! The little black lines are the apothecia, the spore-producing bodies of the lichen. This lichen is found on smooth-barked trees.
I found this Lichen mix growing on a tree in my yard. Note the black prothallus.
spp. (possibly heterospora)Great Smoky Mountains NPFeb. 21, 2009 This warty crustose lichen grew on the bark of a maple tree at Tremont.
The little raised, white structures on this lichen are the soredia, the vegetative reproductive structures found on some crustose lichens.
A close-up photo of lichens on a headstone.
(yellow with orange apothecia) (possibly) Caloplaca flavovirescens? Leakey, TX (Lost Maples SP) March 29, 2009 I found several kinds of lichens growing on the limestone rocks along the trail at Lost Maples State Park.
American Wolf Lichen; Letharia columbiana
Taft, CA March 22, 2007 I found this odd lime-green lichen growing on the north side of a fence post in the mountains above Taft, CA (on the day that I was yearning to see some green grass after spending a week in the desert!). Note the huge, brown apothecia. This lichen gets its name from the fact that it was once used to kill wolves.
A foliose Lichen on a tree.
I got a kick out of seeing the Lichen on this mailbox in Oak Ridge! It is amazing sometimes where lichens can establish themselves and grow! We once had a basketball goal net that was encrusted with them. We have small yellow lichens growing on the cement of our patio and driveway. Lichens do not have roots, so they do not damage the object they grow on.
Some of the nice things about lichen is that you can enjoy them year-round; they grow just about everywhere; they come in a beautiful variety of colors, shapes and textures; and best of all, they don't move in the wind! My poor husband will now have put up with me taking photos of another kind of organism! ;) These lichens were photographed after a snowfall in the Smokies on Feb. 22, 2009. Lichens are incredibly resilient organisms, they can withstand cold, heat, and drought. Their "Achilles' heel" is poor air quality since they absorb water and nutrients from the air. Park rangers and researchers are studying the health of lichens in the higher elevations of the Smokies to help monitor air quality. Lichens grow at an incredibly slow pace, some from 0.1mm to 0.5mm / year! Large lichens can be very old; all the more reason to not damage them!
Bushy Beard Lichen; Usnea strigosa
Oak Ridge, TN January 28, 2009 This strange lichen likes to grow on Maple trees. We have Silver Maples (unfortunately!) in our yard, it is very common to find this strange lichen on the ground after a windy day. Lichens just use tree bark as a substrate to grow on, they do not damage the tree. The flat, fringed patches are the reproductive bodies, called apothecia.
Red Beard Lichen; Usnea rubicunda
- a fruticose lichen Great Smoky Mountains NP Feb. 21, 2009 Unlike its close relative, Usnea strigosa, this lichen does not have the large apothecia and it is not as "fuzzy". A fun fact about the Usnea species is if you carefully pull apart a large branch you will see a white central "cord", a good identifying characteristic.