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// Accessed on December 27.