Searching for Jelly Lichens

Spring is brief in Colorado, making it very important to play hooky this time of year! This post records an adventure from back in May 2009, a wetter spring than Colorado has had in recent years. That made it a perfect time to visit Lair o’ the Bear Park with a friend to see jelly lichens.  

I hadn’t visited for a while, so had to check every cliff to find the right one, way out at the west end of the creekside trail that was once the main road from Morrison to Evergreen, shortly before it enters adjacent Corwina Park.

Eventually we reached the proper cliff, where we could see not only the sought-after jelly lichens, but the wonderful Sticta, and verdant masses of spikemoss, Selaginella. The jelly lichens were soft and slimy from recent rains and lingering rivulets in the cracks and crevices of the cliff. In this photo, a large Umbilicaria (lichen, not a jelly one) is under the ring, with dark Selaginella to its right, and lighter-colored masses of true mosses surrounding.

Properly called gelatinous lichens, these lichens are so named because they lack the firm texture of more typical foliose lichens and have a characteristic translucence when wet. (They remind me of the “tree ears” we sometimes encounter in Chinese restaurant dishes, but those are actual fungi.) Gelatinous lichens are unstratified or only partially so, lacking the distinct algal layer, and sometimes the firm lower and/or upper cortex found in the “typical” lichen (if there is such a thing). The primary phycobiont species is a cyanobacterium, generally Nostoc.

They look so different when they’re dry! This one is, I believe, a species of Leptogium, with a white tomentum visible on the lower surface. Perhaps L. saturninum, but confirmation will have to await another trip. With a hand lens. For those who prefer common names, LoNA* calls this one bearded jellyskin.** (Ugh!)

By the way, you can sometimes find free-living forms of terrestrial Nostoc in Colorado (more commonly here in NY). We’ve seen them on Lyons Sandstone near Red Rocks Park.


* LoNA is Lichens of North America, the coffee table book of lichens, by Brodo, Sharnoff, and Sharnoff. Highly recommended! You can see Sharnoff’s species photos from the book at Sharnoff Lichen pages.

** Jellyskin is the name used here for the entire genus of Leptogium, as opposed to the name “jelly lichen” given only, in that book, to species of Collema, another common jelly lichen. This is the only book I know that assigns common names to lichens; few lichens have true common names.

Lichen Spotlight – Vulpicida pinastri

The Powdered Sunshine Lichen or Vulpicida pinastri is certainly one of the most striking of Colorado lichens. For those of us who like to identify lichen to species it also happens to be highly distinctive!

Vulpicida pinastri – Gregory Canyon, Boulder CO

This species is quite common once you know where to look for it. It likes cool wetter areas in the higher areas of the foothills up to timberline. It is a corticolous lichen, fancy scientist speak for growing on trees of bark. The species has a particular fondness for stumps, especially where humans have cut down a tree. Like other species that prefer exposed wood and not bark, it also grows on other human-made substrates like fences.

It can be rather immediately identified by its erect foliose structure, the intense yellow marginal soredia that look like a crust on the outer edges of the lichen, and a blue-green thallus. This species is almost always sterile, meaning the lichen only reproduces asexually by the dispersal of tiny particles of those beautiful yellow soredia.

Vulpicida pinastri on an old stump, a common substrateGregory Canyon, Boulder CO. Click to enlarge.

I tried to find more about the species’ natural history, and like many lichens there is not much out there. It is a Holarctic species distributed in northern hemisphere in both North America and Eurasia. It can be found in boreal forests and at higher elevations in mountains further south. That’s us in Colorado! One study1 used this species to show that some lichen substances are indeed toxic and are a possible way to limit anything from eating them. Another presentation2 made the bold claim that chemicals produced could have potential in the treatment of Alzheimer’s! At any rate surely there is more to learn about this lichen, but for now head up into the mountains and try and spend some time with your new acquaintance Vulpicida pinastri.

1 Pöykkö, H., Hyvärinen, M., & Bačkor, M. (2005). Removal of lichen secondary metabolites affects food choice and survival of lichenivorous moth larvae. Ecology, 86(10), 2623–2632. https://doi.org/10.1890/04-1632

2 Ureña Vacas, I. M., González Burgos, E., & Gómez-Serranillos, M. P. (2019). Antioxidant capacity and cholinesterase inhibitory activity of vulpicida pinastri lichen and its chemical composition. Proceedings of 5th International Electronic Conference on Medicinal Chemistry. https://doi.org/10.3390/ecmc2019-06317

Life Finds a Way

Underpass to the Highway 36 onramp on Baseline Road, Boulder.

You may well be asking why on earth I have started this post with a picture of an underpass, but on a windy day in Boulder here I was.

I have always been fascinated by the life that manages to persist in heavily disturbed urban areas like the plants sprouting through cracks in the sidewalk. While sometimes easy to simply dismiss the life that persists in these places, to wish that native species could be flourishing instead of the non-native weeds, bugs and animals, I think learning what can live in the midst of all of humanity is a worthwhile task. As I set off my soap box I present to you one such organism.

Flavoplaca citrina (tentative) – Growing on a synthetic fiber. See the retaining wall on the left side of the top photo and you can just barely see the black material with yellow crust on top.

I was quite surprised to see large patches of a yellow lichen growing on some material presumably used to help keep the dirt in place on the retaining wall. I was even more surprised when I looked closer and determined it was a species I had clearly never seen before. When attempting to key out this specimen I had no good answer it asked me what substrate it was growing on! If you believe it construction material wasn’t an option. Presuming I have the species correct in Tom Nash’s excellent Lichen Flora of the Greater Sonoran Desert Region. Vol 3 possible substrates for the species are “on wood, bark, bryophytes, non-calcareous or calcareous rocks.” This to me shows that the species can be rather opportunistic when it comes to where it can grow. Perhaps a reason it chose this man-made material as a home.

Next time you are on a walk through the city and you see a splash of color where you don’t expect take a closer look you may just find a lichen adapting to the new urban environment we have created.

Flavoplaca citrina (tentative) – Showing off it’s apothecia (bright orange discs with yellow rims) which were present on some but not all colonies of the lichen.

One of the main reason’s I wanted to start writing on lichens is to show others how to start identifying them. So watch out I’m going to get technical down here and describe this lichen.

Let’s start with a description of the thallus. Step one, it has a thallus, this is the yellow portions in the above photo, and is the main body of the lichen. In some of the small crustose species the entire thallus can be hidden within the substrate and only the apothecia are showing. The thallus also has no distinct leaf-like shapes at the edges (non-lobate) and only consists of little individual specks (areolate).

Second step color, yellow and orange lichens are rather distinctive and, in general, are going to belong to only a few groups of lichens. When presented by a new yellow or orange species a chemical test with Potassium Hydroxide solution is a good step. Lichen aficionados call this a K test. Fun fact K is a product used for some dermatological applications and is super easy to buy. Please inform your spouse before they ask why you purchased foot fungus medicine. I digress. Treat a small section with the reagent and it may well turn blood red. If this is true you have a member of the family Teloschistaceae, as was true today.

Next step is describe the reproductive structures (I hope for a full post about this soon). In the last photo we have apothecia disc or cup shaped structures, but looking closer there is more.

Microscope view of the areoles (the individual units of yellow above). A continuous thallus is not divided this way. See also the marginal soredia.

Looking closer we see powdery masses on the margins, these are soredia. This powder can disperse in the wind or hitch a ride on an animal and if it find the right place to live a new lichen can form. Lichens are weird, as you may have picked up on, this specimen reproduces both sexually (apothecia) and asexually (soredia). Talk about keeping our options open.

Hopefully those that kept reading learned a new term of two. Identifying lichens can be extremely hard, and a good key is necessary, or even specialized equipment. If you think I blundered this ID (very likely) let me know I would love to know why.

Iceland “moss,” Cetraria islandica

Cetraria islandica, a true lichen known as Icelandic moss, captured as an ingredient in “Icelandic schnapps.”

An unexpected encounter last week reminds me to talk about one of my favorite lichens! Cetraria islandica is not entirely rare in Colorado, but I would guess it’s rarely seen by most of us. For one thing, it occurs at higher elevations, above, say, 8000 ft. (~2440 m) It’s also cryptically colored, blending in with the forest floor, where it can be confused with other small plants, mosses, and lichens carpeting the soil.

Steeped in alcohol, "Iceland moss" becomes Icelandic schnapps—definitely an acquired taste.

Steeped in alcohol, “Iceland moss” becomes Icelandic schnapps—definitely an acquired taste.

But the lichen I encountered last week, at a friend’s house, was in a bottle, lending flavor and perhaps substance to a concoction called Icelandic schnapps. Of course, I had to taste it, and he was kind enough to oblige. Knowing he had laboriously carried it home from a visit to Iceland, I did not ask for a second glass.

Cetraria islandica is one of a few species known to occur in Colorado, although they will be more common at higher altitudes (or latitudes!). All are fruticose, after a fashion, and more or less brownish in color. (Clarity is helped here by the fact that the yellowish species are now in a separate genus: Flavocetraria.)

According to CNALH: “Cetraria ericetorum is distinguished from C. islandica … by having a consistently P- medulla, and by the pseudocyphellae being strictly marginal and sometimes indistinct or absent. Cetraria ericetorum ssp. reticulata belongs within the C. ericetorum complex comprising three mainly geographical races. Subspecies. reticulata basically comprises the subspecies occurring in North America.”

Cetraria aculeata is more truly tangled and shrubby, its branches more rounded than flattened. It was once in a separate genus, called Cornicularia.

California gets a State Lichen!

This month, California became the first state to designate an official State Lichen. Based on the efforts of the California Lichen Society, the state legislature approved the lichen last summer and the law was signed by Governor Jerry Brown in July, but didn’t take effect until January 1, 2016.

Ramalina menziesii, lace lichen. Photo courtesy Greg Howe.

Meet Ramalina menziesii,
the Lace Lichen

finRmenziesiiAlthough one of several lichens that drape themselves in trees in long graceful strands, the Lace Lichen is distinctive and instantly recognizable. Unfortunately for the rest of us, this beautiful lichen occurs only along the west coast of North America. However, this makes it a perfect candidate for California’s state lichen: it is common along the coast and as much as 130 miles inland. No other lichen has the lacey or netted branches, although some species of Usnea or Alectoria appear similar from a distance.

Learn more about Lace Lichen and its designation at the California Lichen Society webpage. But remember, it’s a lichen, not to be confused with “Spanish moss” (which is not a moss either)!

Lichens by Haeckel 1904

Lichenes illustration by Ernst Haeckel, labeled to match the key below. Via Wikipedia, public domain.

Lichenes illustration by Ernst Haeckel, labeled to match the key below. Via Wikipedia, public domain.

Via Wikipedia, this great illustration of “Lichenes,” drawn by Ernst Haeckel to emphasize his ideas of symmetry in his Artforms of Nature, published in 1904. Click to enlarge.

Haeckel’s stylized drawings convey these lichens in their most basic forms, with much of their random meandering growth reduced to precision, as evidenced in the strict circles of #8 and #9, the ovals of #10 and #11. Despite the fact that, in the field, these are apt to appear far less uniform in shape, Haeckel has captured the “personality,” if you will, of each species, making them reasonably recognizable.

Just for fun, in the key below, we’ve linked some of the species names to a current photo from other websites for comparison. Links open in a new window; use your browser’s back button to return here.

Tafel_083_schema_300Here’s the key to these drawings, by number, with some synonymy of a more recent day added, apparently by the annotator for Wikipedia.
1. Cladonia retipora (Floerke) = Cladia retipora (Labill.) Nyl. (an Australian species, but here’s a photo from Pinterest)
2. Cladonia perfoliata (Hooker) = Cladonia perfoliata
3. Cladonia verticillata (Achard) = Cladonia cervicornis ssp. verticillata (Hoffm.) Ahti
4. Cladonia squamosa (Hoffmann) = Cladonia squamosa (Scop.) Hoffm.
5. Cladonia fimbriata (Fries) = Cladonia fimbriata (L.) Fr.
6. Cladonia cornucopiae (Fries) = Cladoniaceae sp.?
7. Sticta pulmonaria (Achard) = Lobaria pulmonaria (L.) Hoffm.
8. Parmelia stellaris (Fries) (non (L.) Ach.: preoccupied) = Physcia stellaris or Physcia aipolia (Ehrh. ex Humb.) Fürnr.
9. Parmelia olivacea (Achard) = Melanohalea olivacea (L.) Essl.
10. Parmelia caperata (Achard) = Flavoparmelia caperata (L.) Hale
11. Hagenia crinalis (Schleicher) = Anaptychia crinalis (Schleich.) Vězda

If you appreciate the elegance of nature, as Haeckel clearly did, you should look at this entire book. Browsing through the illustrations was like an instant review of invertebrate zoology and paleontology courses from college. Many of his drawings feature protozoans, medusoids, and other familiar lifeforms in those textbooks (if not in life); these would have enhanced some of those courses! Explore more at:

Kunstformen der Natur, Haeckel, Ernst, 1834-1919, Bibliographisches Institut Leipzig. Contributed to Biodiversity Heritage Library by University of Illinois Urbana Champaign.

Stereocaulon, Easy to Spot

This genus is readily recognizable, but a challenge to identify to species without a microscope or chemical tests. Stereocaulon is very unusual in structure, even for a lichen. It is generally considered a fruticose lichen, but “it’s complicated.” They have been given the common name “foam lichens,” which certainly seems fitting.

Stereocaulon sp., by Jack R. Darnell. On soil, Pike National Forest near Staunton State Park.

Stereocaulon sp., by Jack R. Darnell. On soil, Pike National Forest near Staunton State Park.

These fluffy, feathery fruticose-looking lichens actually consist of a crustose primary thallus that develops a secondary thallus of branched stalks, sometimes called pseudopodetia. In most species, the crustose part of the thallus disappears, leaving no clue that this critter is anything but fruticose.

To identify species, you also need to master a specialized vocabulary. Growing on the branches of Stereocaulon are granules or squamules called phyllocladia. The phyllocladia, whether flat or coral-shaped, contain Trebouxia, a green alga commonly found as a lichen photobiont. Nestled among them we may often find structures called cephalodia (you may recall we saw these in Peltigera as well). The cephalodia contain cyanobacteria, often Nostoc.

Closer view of Stereocaulon from previous photo by Jack R. Darnell.

Closer view of Stereocaulon from previous photo by Jack R. Darnell.

In this closer view, no apothecia are seen. I wouldn’t call this “mat-forming, without main stems,” so that kinda rules out S. rivulorum. Options (in LoNA key) for phyllocladia are “granular to squamulose, rarely coralloid” versus “warty, sometimes lobed.” What do you think? If I had to make a wild guess, I’d say Stereocaulon glareosum, which has been reported from the area.

I’d also say we need a dissecting microscope. This is why we like to talk about genera more than species! (And why we’ll maybe tackle an easier species next time!)

According to my search of collections at Lichen Portal (CNALH), in Colorado we have 15 taxa in 11 species of Stereocaulon, with some specimens not identified to species. Most of these collections are at elevations above 2400 m (8,000 ft). Our species are:

  • Stereocaulon albicans
  • Stereocaulon alpinum
  • Stereocaulon dactylophyllum
  • Stereocaulon glareosum (retains primary thallus; cephalodia brown)
  • Stereocaulon glareosum var. brachyphylloides
  • Stereocaulon incrustatum
  • Stereocaulon microscopicum
  • Stereocaulon myriocarpum
  • Stereocaulon myriocarpum var. orizabae
  • Stereocaulon paschale
  • Stereocaulon paschale var. alpinum
  • Stereocaulon rivulorum (arctic-alpine, no apothecia)
  • Stereocaulon subalbicans
  • Stereocaulon tomentosum (thallus erect, not matted; tomentose; apothecia common, brown and terminal; cephalodia blue-black)
  • Stereocaulon tomentosum var. compactum

Of the 11 species (357 specimens identified to species), most commonly collected here are S. tomentosum (129), S. glareosum (85), S. rivulorum (69), and S. alpinum (45). Chances are this specimen is one of these four. If just going by these photos, I’d love to say it’s S. rivulorum!

Stereocaulon alpinum photo at Sharnoff Photos
Stereocaulon rivulorum photo at Sharnoff Photos
Stereocaulon tomentosum photo at Sharnoff Photos

Data summarized from:
Consortium of North American Lichen Herbaria (CNALH). 2014. http//:lichenportal.org/portal/index.php. Accessed on December 27.

Umbilicaria, or Rock Tripe

Umbame1882Umbilicaria americana, FROSTED ROCK TRIPE
This species and its relatives are known as “rock tripe” and said to be edible, though perhaps only in dire situations. For example, the related species Umbilicaria mammulata reportedly fed George Washington and his starving troops during the harsh winter of 1777 at Valley Forge. A distinctive and abundant lichen on moist, vertical cliff faces in the Front Range, it lacks apothecia and has a sooty black underside covered with rhizines, creating a velvety appearance.

umbil2346smThalli are leathery (and green!) when wet, and are “umbilicate” (attached only at one central point); they can be 15 cm across. Largest and most notable of our umbilicate species, this often grows in huge colonies.

Another large species of Umbilicaria, this brownish one with abundant black apothecia and a more wrinkled upper cortex. Perhaps U. hyperborea.

Fun fact: Some species of Umbilicaria have intriguing black “gyrose” apothecia with concentric fissures. This species, however, is rarely seen with apothecia.

Don’t be fooled: Umbilicaria vellea is similar, but usually smaller and generally found at higher elevations or latitudes. Details of the rhizines distinguish the two.

A monotypic colony of Umbilicaria on metamorphic rock cliffs in Bear Creek Canyon, Jefferson Co., Colorado.

A monotypic colony of Umbilicaria on metamorphic rock cliffs in Bear Creek Canyon, Jefferson Co., Colorado.

Old Man’s Beard, the Genus Usnea

Long pendulous thallus of Usnea cavernosa, found on conifers in Rocky Mountain National Park, the San Juan Mountains, and other high elevations in Colorado. Not common here; this scan is of a specimen from Idaho.

Some fruticose lichens form long webs, dangling from tree branches, that acquire common names like “tree hair” or “old man’s beard,” especially in places like the Pacific Northwest, where high humidity and tall trees support their robust expression. From a distance, these resemble the “Spanish moss” of southern states (which is neither moss nor lichen).

Common species of Usnea, such as U. hirta and U. subfloridana, occur on conifer bark and are small and shrubby.  At higher elevations with adequate moisture, larger species like U. cavernosa may be seen.

Common species of Usnea, such as U. hirta and U. subfloridana, occur on conifer bark and are small and shrubby. At higher elevations with adequate moisture, larger species like U. cavernosa (at top) may be seen.

More common in our Colorado forests are species of Usnea that display themselves less dramatically. Most are no more than a few inches tall (or long) and are frequently seen on bark of conifers like Douglas-fir and Colorado or Engelmann spruce. (Oddly, however, not on ponderosa pine.)

A closer view of this same specimen is below; click to enlarge further.

A close-up of the same lichen shows the tangled branches characteristic of the Usnea thallus. Each branch has a tough central cord, which distinguishes this genus from other light-green arboreal species.

A close-up of the same lichen shows the tangled branches characteristic of the Usnea thallus. Each branch has a tough central cord, which distinguishes this genus from other light-green arboreal genera, like Evernia and Ramalina.

Detailed description of Usnea cavernosa
More Usnea photos (at Ways of Enlichenment)
List of Usnea species and photos (at Sharnoff Lichens)

Peltigera leucophlebia

Or is it Peltigera aphthosa? Only by peeking underneath can you be sure! This post was published as a lichen profile in the Winter 2013 issue of Aquilegia, newsletter of the Colorado Native Plant Society (Vol 37, No. 6). Back issues are available online at the CoNPS website..

Peltigera leucophlebia, Peltigera aphthosa

Photo by Rick Brune.

Photo by Rick Brune.

Broad, ruffled lobes would place the abundant “pelt” lichens among the most noticeable of our montane lichens, were it not for their usual cryptic brown and gray coloring. Fortunately three of our 15 species stand out, at least when wet, thanks to the chlorophytes that are their primary photobionts. Peltigera aphthosa and Peltigera leucophlebia (clear veins) are large lichens with bright green coloring that helps us spot them when the forest floor is moist. The 2-4 cm wide lobes radiate to form a thallus 30 cm or more across.

To distinguish these two species, you’ll probably have to take a peek at the underside. P. leucophlebia, as its name implies, has distinct veins that change from light colored near the margin to black toward the center. Carefully loosen the lichen from the soil or mosses to check for this. In P. aphthosa, the veins tend to be broad and undefined. The uplifted lobes bearing brownish apothecia have, in P. aphthosa, green cortex on the underside of these reproductive structures, but in P. leucophlebia, the cortex is absent or present only as green specks on the white background.

Fun fact: Round dark structures on the upper surface, called cephalodia, contain cyanobacteria, giving these lichens claim to a three-kingdom symbiosis.

Don’t be fooled: Species of Sticta look like Peltigera and are in the same family, but the underside is black with white spots instead of the characteristic veins. Our third green Peltigera, P. venosa, is smaller (less than 2 cm diameter) and each fan-shaped thallus consists of a single lobe, usually with black marginal apothecia.

Scans of upper (left) and lower (right) surfaces of Peltigera leucophlebia, by Richard Brune.

Scans of upper (left) and lower (right) surfaces of Peltigera leucophlebia, by Richard Brune.