Niebla homalea

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
April 2003, Oct 2005, Sep 2012, Feb 2017

Niebla and Vermilacinia (Ramalinaceae) from California and Baja California.  
Spjut, R.W., 1996. ISSN 0833-1475, 208 pp.  
Sida, Botanical Miscellany 14. Botanical Research Institute of Texas, Inc.


homalea-Bodega.jpg (198531 bytes)

Sonoma Co., Just N of Bodega Bay, CA, Spjut s.n., Sep 2002

homalea-10244.jpg (52141 bytes)

Bahía de San Quintín, BCN,
Spjut 10244, Mar 1988

homalea-13068.jpg (318845 bytes)

Pendulous, rock face below
Mesa Camacho, N of Punta Canoas, Spjut & Marin 13068, Apr 1994

homalea-9032H.jpg (38511 bytes)

Punta Banda, BCN,
Spjut & Marin 9032H


San Cruz Island, CA
Bratt 6432

San Francisco Watershed Dist,
4 mi from Junipero Serra Freeway, CA. Selva 106 (COLO, US)

Marin Co., Pt. Reyes, CA
Weber (COLO: S-1185)


Santa Cruz Island, CA
Schuster 37
(COLO: 47736)

Marin Co., Pt. Reyes, CA
Imshaug 17888 (COLO: S-13467)

San Mateo Co.,
Pilarcitos Canyon, CA
ABL Foray (COLO: S-14778)

Lectotype from California

Geographical occurrences

Baja California: Bahía de San Quintín
Spjut & Sérusiaux 17026A,
 Jan 2016, Field id N. homalea
Confirmed  by TLC Oct 2016, isodivaricatic acid + terpenes

Point Navarro Preserve, Mendocino Co., CA., File no.
Niebla homalea 24096.jpg


     Niebla homalea (Acharius) Rundel & Bowler is a lichen that was first described by Acharius in 1810 as a species of Ramalina from specimens collected on rocks in California, most likely near San Francisco.  Today, the species is recognized to range from Isla Guadalupe and slopes below Mesa Camacho in Baja California Norte to Point Navarro Preserve in Mendocino Co., CA.  The species is characterized by a thallus divided into ribbon-like branches that are either simple or occasionally divided into secondary branches of unequal length, by branch margins that twist 90° at frequent intervals, by a glossy cortex transversely cracked at various intervals, and by containing divaricatic acid (with triterpenes). 

     However, Niebla homalea has a long controversial history of how it should be defined.  It may be the only species of a genus distributed in the New World (North and South America; Montagne 1852), one of ~12 species in the New World and six in the Mediterranean region (Bowler & Marsh 2004), or one of more than 42 species in North America excluding 18 species classified in another genus, Vermilacinia (Spjut 1996).

     In 1852, Montagne recognized Ramalina homalea as belonging to a new genus he named Desmazieria.  Unfortunately, this was similar to “Desmazeria” named earlier by Dumortier 1822 for a genus of grasses.  Although lichens have little in common with grasses, the International Rules of Botanical Nomenclature (ICBN) allow only one name, the later homonym by Montagne must be rejected unless conserved.  Follmann (1976), who apparently discovered Dumortier's earlier name, stated that the names for the two genera “do not sound sufficiently similar that they are likely to be confused.  Therefore, the genus name Desmazieria Mont. can be retained.”  However, Rundel and Bowler (1978) disagreed; they created the substitute name Niebla.

     Sérusiaux, van den Boom, and Ertz (2010) erroneously stated that "only D. ceruchis was mentioned by Montagne (1852) in the original publication,” and from this error they had concluded that “Niebla ceruchis must be the type species.”  This error may have come from Krog & Østhagen (1980) who stated D. homalea [Montagne 1852] was a synonym of D. ceruchis [(Acharius) Trevisan 1861], while it may also be noted that Sérusiaux et al. (2010) did not cite Montagne (1852).

     Montagne's name for the one species was clear, “Desmzieria homalea Montag.”  His description of the species was followed by reference to synonyms that included not only his Usnea ceruchis, but earlier synonyms “Borrera ceruchis Ach.?” and “Ramalina ceruchis” De Notaris (1846).  Since Montagne (1852) recognized only one species, the type has to be Desmazieria homalea (Acharius) Montagne 1852 (ICBN Art. 7.1–7.4), which is now Niebla homalea (Acharius) Rundel & Bowler 1978.

     Part of the confusion may relate to Montagne's (1834, 1844, 1852) previous treatments of Desmazieria based largely on his study of South American specimens of the genus now called Vermilacinia (Spjut 1995)Prior to his 1852 publication on D. homalea, he had considered it a species of Usnea, which he later transferred to Evernia; originally it was Parmelia ceruchis Acharius (1803) based on lichen specimens collected near Lima, Peru.  Acharius' type closely resembles a specimen collected by Charles Darwin from near Iquique (northern Chile) in July 1835, who described the lichen as “lying without adhesion on bare other plant on the coast for 16 leagues inward” [FH specimen cited by Spjut 1996; Beagle arrived Lima 19 July 1835, left Callao Sep 7,] Montagne (1834), in referring to it as Usnea ceruchis, noted that it also occurred abundantly on rocks around Callao Peru, a rocky peninsula ~12 km west of Lima   (, and on branches of shrubs, and on cactus near near Coquimbo in Chili (Montagne 1834, in reference to Gaudichaud, specimens at FH and US cited by Spjut).  His (Montagne 1834) illustration, reproduced here, appears to include a saxicolous variant at Callao, Peru (V. aff. ceruchis) and corticolous species at Coquimbo Chile (V. tigrina, V. leopardina; Spjut, 1995, 1996), but not the typical terricolous form (see Vermilacinia).


     In 1844, Montagne decided that his Usnea ceruchis did not belong to that genus and transferred it to Evernia Acharius, “Evernia roccellaeformis Montag.” based on Ramalina rocellaeformis Bory 1829, although he or someone else had earlier annotated a specimen Evernia ceruchis var. rocellaeformis (Spjut 1996, specimen cited, FH). The relationship to Ramalina was made clearer by de Notaris (1846) who regarded Montagne's (1834) illustration as useless and reckless, certainly apparent by his rendition of fringed apothecia to make it resemble a species of Usnea.

     Today Vermilacinia ceruchis and Niebla homalea are not only considered different species; they belong to different genera.  Niebla sensu Spjut (1996) does not occur in South America. Notwithstanding, the type for Niebla homalea has to be based on that name no matter how far off Montagne (1852) was in his description of the species—now recognized to occur only in North America; “Borrera ceruchis” Acharius does not always necessarily equal “Ramalina homalea Acharius” even though Montagne considered them to be synonymous.  The lichen genus Borrera (Acharius 1803) was later rejected in favor of conserving the flowering plant genus, Borreria (G. Meyer 1818) in the Rubiaceae; Acharius' (1810) species included not only B. ceruchis, but others that have since been transferred to the lichen genera Teloschistes and Seirophora.

     Further confusion has been generated by Bowler (1981), Bowler et al. (1994), and Bowler & Marsh (2004) in referring the South American saxicolous/terricolous (rock-earth dwelling) V. ceruchis to his North American corticolous (growing on living bark) species Niebla ceruchis, while also recognizing North American saxicolous V. ceruchoides and V. combeoidesVermilacinia ceruchis does not occur in North America (Spjut 1995, 1996). Sipman (2011) recently described two new species of Niebla, which occur only in South America, one of which belongs to Vermilacinia subgenus Cylindricaria.  Despite inconsistencies in the taxonomic treatments, Sipman's (2011) segregation of new species essentially reinforces Spjut's (1995, 1996) separation of the South American V. ceruchis from related species in North America. A distinctive feature of the V. ceruchis complex in South America (Subgenus Vermilacinia) is the lateral to subterminal position of apothecia (Bory 1828; Montagne 1834; Spjut 1996). However, the type, an earth-growing form (terricolous) without apothecia, may be an extinct species (Follmann 1994).

     The colloquial expression 'history has a way of repeating itself' seems relevant here. Instead of Vermilacinia and Niebla, more than 200 years ago these were Borrera and Ramalina (pro parte, Acharius 1810, 1814).  As with Bowler et al. (1994, 2004) who combined Vermilacinia with Niebla, Montagne (1834, 1844, 1852) could not satisfactorily distinguish the species—and after studying them for more than 18 years—he combined them (Usnea ceruchis, Ramalina homalea) into a new genus (Desmazieria Montagne 1852).  Rather than use the epithet ceruchis as he had done in the past, it would appear that Montagne may have wanted to further emphasize the extreme variation he saw as one species by selecting the epithet from Ramalina homalea, which thus became the basionym for Desmazieria homalea; its type specimen therefore is automatically based on Ramalina homalea Acharius.  Later authors continued to keep the species separate, however, either in Desmazieria, which became Niebla (Trevisan 1861; Follmann & Huneck 1959; Rundel & Bowler 1972, 1978), or in Ramalina (Nylander 1870; Howe 1913; Stevens 1988).  The fact that D. ceruchis was later recognized as a separate species from D. homalea, does not mean that it replaces the type for the genus.

    Subsequently, Rundel and Bowler (in Rundel et al. 1972), recognized two additional species under the illegitimate Desmazieria, Niebla sensu Spjut (1995, 1996), later legitimized in Niebla (Rundel & Bowler 1978), N. josecuervoi and N. pulchribarbara from thalli growing around Bahía de San Quintín, Baja California Norte.  However, their 'beautiful' lichen N. pulchribarbara was subsumed under N. josecuervoi, (Bowler and Marsh 2004) in further honor of their field assistant who the lichen was named after. Thus, only three North American species of Niebla sensu Spjut were recognized by Bowler and Marsh (2004; N. homalea, N. isidiaescens, N. josecuervoi).

   It is interesting to note that Vermilacinia laevigata (Niebla laevigata, Bowler et al. 1994) had been overlooked for many years because of its superficial resemblance to N. homalea.  Mason Hale's (Hale & Cole 1988)  Lichens of California included a color photograph of Vermilacinia laevigata referred to as N. homalea despite knowing that it might potentially be V. halei Spjut (unpublished) from his review of Spjut's manuscript and numerous specimens at the Smithsonian Institution with this name, and from Spjut's review of his manuscript for which he remarked that his Niebla names were probably not correct.  Unfortunately, V. halei Spjut in editus had to be retracted from publication, because Bowler et al. (1994) published their name (N. laevigata) as Spjut (1996) was in press.

     Howe (1913), who monographed the North American Ramalina, was obviously aware of the morphological differences between Vermilacinia and Niebla—by his remark that he considered the chondroid strands of Ramalina (Niebla) “almost of generic importance”—and perhaps would have treated them in different genera had he had the chemical tools of modern lichenology such as microcrystal tests (1930's–) and thin-layer-chromatography (TLC, 1950's–).  Additionally, it appears that misidentification of an unknown triterpene (T3, Spjut 1996), referred to as  methyl 3,5 dichlorolecanorate by Rundel & Bowler on their chemical annotation labels of specimens at the US (Smithsonian Institution, herbarium), and the lack of clear reference to the key chemotaxonomic diterpene in Vermilacinia tuberculata by Riefner et al. (1995, as Niebla tuberculata), which was not clearly distinguished from zeorin, may explain their inability to accept Vermilacinia (Spjut 1995).  Another problem is that chemical differences in these lichens are not distinguishable by chemical spot tests, introduced by Nylander during the 1860's (Molnára & Farkas 2010) at which time lichenologists considered lichen species based on chemical differences nonsense, although some mycologists today, who review NSF grants, still hold that view

     Going forward, Niebla homalea sensu Spjut (1996) is obviously more narrowly defined than in Bowler et al (1994).  As indicated above, it is distinguished from related species by the ribbon-like branches that divide unequally (one branch shorter than other), or the branches do not divide but remain simple.  It is further characterized by apothecia developing near the apex (subterminal), by having a glossy cortex cracking transversely at various intervals, and by producing secondary metabolites divaricatic acid with triterpenes and pigment skyrin. 

     Among the related species that contain divaricatic acid, N. testudinaria and N. eburnea are the most difficult to distinguish from N. homalea. Their differences are summarized in the following table.


N. homalea

N. eburnea

N. testudinaria





Branching general




Terminal bifurcate

Usually not evident.

Usually not evident.


Branch shape lengthwise




Branch shape cross-section



Elliptic, prismatic, or ±4-angled.

Branches twist

Frequent between base and apex.

Half twist near base and apex.

Frequent between base and apex.

Branch margin

Usually well-defined,  acute.

Rounded to acute, usually thickened, wrinkled in upper half of thallus.



Glassy, transversely cracked at various intervals.

Creamy frosting or like a glazed donut, irregularly transversely cracked or pleated.

Dull, transversely cracked and reticulate ridged between margins.


Subterminal on short branch-like segments, often perpendicular to branch margin.

Usually subterminal, often in plane with the branch.

Usually absent, subterminal in type,  elevated from main branch by a short flattened lobe.

     It may also be noted that both Nylander (1870) and Howe (1913) distinguished Niebla testudinaria from N. homalea (under Ramalina).  Their studies were more than just casual; both lichenologists monographed Ramalina. Spjut (1996) further clarified the differences between these species by recognizing N. eburnea, and others with divaricatic-acid and depsidones. 

     The problem in dealing with the variation in Niebla is that there are many species in the genus that need to be sorted out before any of them can be clearly identified.  Mason Hale once asked if there were new species at every new location I encountered Niebla.  The Niebla and Vermilacinia complexes comprise one of the most variable and poorly understood lichen groups on the planet. They are also vanishing; for example, a morphological variant of N. disrupta, distinguished in part by having sekikaic acid, was collected by Riefner in 1986 on rocks just above the littoral around Morro Bay where he had reportedly found it to be abundant, but I did not see any Niebla around Morro Bay when I looked for it in Feb 2011.  Additionally, conservative taxonomic views on Niebla (Bowler & Marsh 2004) would seem to mask many rare species of Niebla and Vermilacinia that may need protection. 

References Cited

Acharius, E. 1803. Methodus qua omnes detectos lichenes. Stockholm.

Acharius, E. 1810. Lichenographia universalis. Gottingen.

Bory, St-V., de. 1828. Cryptogamie. In Voyage autour du monde, par M. L. I. Duperrey, capitaine de Frgate. Arthus Bertrand, Paris.

Bowler, P. A, R. E. Riefner, Jr., P. W. Rundel, J. Marsh & T.H. Nash, III. 1994. New species of Niebla (Ramalinaceae) from western North America. Phytologia 77: 23-37.

Bowler, P. A. and J. Marsh.  2004. Niebla.  Lichen Flora of the Greater Sonoran Desert 2: 368–380. 

De Notaris CG, 1846. Prime linee di una nuova disposizione de Pirenomiceti Isterini. Giornale Botanico Italiano 2, part I, fasc. 7-8: 5-52.

Follmann, G.  1976. Zur Nomenklatur der Lichenen. III. Uber Desmazieria Mont. (Ramalinaceae) und andere kritische Verwandtschaftskreise. Philippia 3:85-89.

__________1994. Darwin's “lichen oasis” above Iquique, Atacama Desert rediscovered. International Lichenological Newsletter 27: 23-25.

Hale, M. E. Jr. and M. Cole. 1988. Lichens of California. Univ. California Press.

Howe, R.H., Jr. 1913. North American species of the genus Ramalina. Bryologist 16: 65-74.

Krog, H. & H. Østhagen. 1980. The genus Ramalina in the Canary Islands. Norwegian J. Bot. 27:255-296.

Meyer, G. F. W. 1818.  Primitiae Florae Essequeboensis. Gottingae: Sumptibus H. Dieterich.

Molnára, K.  and E. Farkas. 2010. Current results on biological activities of lichen secondary metabolites: A review. Z. Naturforsch. 65 c, 157–173.

Montagne, D.M. 1834. Description de plusierus nouvelles espces de cryptogames dcouvertes par M. Gaudichaud dans l'Amrique mridionale. Ann. Sci. Nat. Sr. 2, 2:369-373 & pl. 16, fig. 1.

 __________. 1844. Botanique. In Voyage de la Bonite, C. Gaudichaud & A. Bertrand, eds. Roi, Paris.

__________. 1852. Diagnoses phycologicae. Ann. Sci. Nat. Sr. 3, 18, 302-319.

Nylander, W.  1870. Recognitio monographica Ramalinarum. Bull. Soc. Linn. Normandie, Sér. 2, 4:101-181.

Rundel, P.W.,  P.A. Bowler & T.W. Mulroy. 1972. A fog-induced lichen community in northwestern Baja California, with two new species of Desmazieria. The Bryologist 75: 501–508.

Rundel, P.W. and  P.A. Bowler, 1978. Niebla, a new generic name for the lichen genus Desmazieria (Ramalinaceae). Mycotaxon 6:497-499.

Sérusiaux, E., P. Van den Boom, and D. Ertz. 2010. A two-gene phylogeny shows the lichen genus Niebla (Lecanorales) is endemic to the New World and does not occur in Macaronesia nor in the Mediterranean basin.  Fungal Biology 114: 528-37.

Sipman, H.J.M. 2011.  New and notable species of Enterographa, Niebla, and Sclerophyton s. lat. from coastal Chile. Bibliotheca Lichenologica 106: 297-308.

Spjut, R. W. 1995. Vermilacinia (Ramalinaceae, Lecanorales), a new genus of lichens. Pp. 337-351 in Flechten Follmann; Contr. Lichen. in honor of Gerhard Follmann, F. J. A. Daniels, M. Schulz & J. Peine, eds., Koeltz Scientific Books, Koenigstein.

_________. 1996. Niebla and Vermilacinia (Ramalinaceae) from California and Baja California. Sida, Botanical Miscellany 14: 1–207, 11 plates.  

Stevens, G. N. 1988.  The lichen genus Ramalina in Australia.  Bulletin of the British Museum (Natural History), Botany Series 16: 107–223.

 Trevisan, V. G. 1861. Ueber Atestia eine neue Gattung der Ramalineen aus Mittel-Amerika. Flora 4:49-53.