Niebla homalea

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
April 2003, Oct 2005, Sep 2012, Dec 2021, Sep 2022

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.

Spjut R, Simon A, Guissard M, Magain N, Sérusiaux E. 2020. The fruticose genera in the Ramalinaceae (Ascomycota, Lecanoromycetes): their diversity and evolutionary history.  MycoKeys. 73: 1–68, published online.
MycoKeys. 2020;73:1-68. Published 2020 Sep 11. doi:10.3897/mycokeys.73.47287

Evolution and diversification of Niebla
Steve Leavitt et al., Baja California, Dec 2016

Jorna J, J Linde, P Searle, A Jackson, M-E Nielsen, M Nate, N Saxton, F Grewe, M de los Angeles Herrera-Campos, R Spjut, H Wu, B Ho, S Leavitt, T Lumbsch.  Species boundaries in the messy middle -- testing the hypothesis of micro-endemism in a recently diverged lineage of coastal fog desert lichen fungi. Ecology and Evolution. Published Online: 20 Dec 2021.

Additional References and additional phylogeography data: See Niebla.



Bahía de San Quintín
Spjut & Sérusiaux 17026A,
 Jan 2016

Bahía de San Quintín
Spjut & Sérusiaux 17030,
 Jan 2016

Bahía de San Quintín
Spjut & Sérusiaux 17042,
 Jan 2016

Marin County, CA: 17801-02
Phylogeny, location, specimens
Niebla homalea in two ITS clades. TLC profile for selected species of Niebla received from Dr. Harinantenaina Liva Romuald Rakotondraibe at the Ohio State University, Oct 2017, for California specimens, L7-L9. Note the difference in triterpenoids between L7 (Stinson Beach) and L9 (Pt. Reyes), Marin Co. Image of thallus in it natural habitat is 17806, at Pt. Reyes. They compare most favorably with the lectotype.

BC: ITS 17026a, 030, 042.
Niebla homalea in two or three clades, all collected in the vicinity of Bahía de San Quintín

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, BC,
Spjut & Marin 9032H


homalea-10244.jpg (52141 bytes)

Bahía de San Quintín, BC
Spjut 10244, Mar 1988


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

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


Lectotype from California 


San Cruz Island, CA
Bratt 6432


homalea-Bodega.jpg (198531 bytes)

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


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


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

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


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

Geographical occurrences 

     Niebla homalea (Acharius) Rundel & Bowler is a fruticose lichen first described by Acharius in 1810 as a species of Ramalina from specimens collected on rocks in California, most likely near Point Reyes in Marin County.  The species is characterized by a thallus containing divaricatic acid (with triterpenes) and by divided into narrow ±cylindrical branches, which occasionally  divide into secondary branches of unequal length.  The branch margins frequently twist 90°. The cortex is usually glossy and transversely cracked at various intervals. 

     Niebla homalea is widely distributed from Point Navarro in Mendocino County, California, to Isla Guadalupe and slopes leading up to Mesa Camacho in the northern half of Baja California peninsula.

      A 6-loci phylogenetic tree of Niebla homalea (Spjut et al. 2020) shows the species in  a large clade sister to N. turgida collected near San Antonio del Mar.  The California  and Baja California specimens belong to separate sister subclades and both include N. eburnea, which also occurs elsewhere in the phylogenetic tree. The Baja California subclades include other species identifications such as N. testudinaria, N. juncosa var. spinulifera and N. flagelliforma.  These subclades represent separate cryptic species complexes in California and in Baja California. Niebla homalea in a strict sense may prove endemic to Marin County; the putative type is from Point Reyes.  BPP analysis delimited three species. Most specimens were found associated with N. eburnea.  Jorna et al. (2021) reported they prepared a draft genome from a specimen representing N. homalea  collected from Sonoma Coast State Park, Shell Beach. This draft has been published (Ametrano in Duong et al. 2021).

     The Niebla homalea species complex is not the only example in which thalli found growing in close proximity to one another show up in different genomic clades as shown above for Niebla homalea specimens collected on the Pt. Reyes Peninsula.  This is commonly seen in many if not most phenotypic species.  Examples in the depside group include N. contorta, N. dilatata, N. lobulata, N. rugosa and others. These complexes may be regarded to consist of cryptic species, and/or in other cases cryptic hybrids where phenotypic differences are evident in the sister clades. This may involve variation in chemotypes such as seen with N. effusa and N. palmeri.  Hybridization seems the best explanation for  hybrid chemotypes between N. spatulata and  N. contorta, especially where fusion of thalli are evident.

         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 Code of Nomenclature (ICN) allows 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.

       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.

       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.  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

    Triterpenoids in Niebla homalea include novel stictanes, named nieblastictanes and nieblaflavicanes (Zhang et al. 2020; Diaz-Allen et al. 2021).  Presumably these or similar triterpenoids are found in all depside species of Niebla.

     Penicillium aurantiacobrunneum was cultured from the specimen collected at Point Reyes (17806). Isolated from this fungal associate were 4-epi-citreoviridin, 15 auransterol, and two analogues of paxisterol, along with two known metabolites (Tan et al. 2019).  Additional studies continue on paxisterol; see under Tan et al. (2019).

     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. 


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

Acharius, E. 1810. Lichenographia universalis. Gottingen.

Ametrano C, Y Sun, I DiStefano, S Huhndorf, H. Thorsten Lumbsch, and F Grewe. 2021. Draft Genome of Niebla homalea. In: Duong TA, J Aylward, CG Ametrano, B Poudel, QC Santana, PM Wilken, A Martin, KS Arun‑Chinnappa, L de Vos, I DiStefano, F Grewe, S Huhndorf, H Thorsten Lumbsch, JR Rakoma,, B Poudel, ET Steenkamp, Y Sun, MA. van der Nest, MJ Wingfeld, N Yilmaz, and BD Wingfeld. 2021. IMA Genome - F15. Draft genome assembly of Fusarium pilosicola, Meredithiella fracta, Niebla homalea, Pyrenophora teres hybrid WAC10721, and Teratosphaeria viscida IMA Fungus. Open Access

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.

Diaz-Allen, C., R. W. Spjut, A. Douglas Kinghorn, and H. L. Rakotondraibe. 2021. Prioritizing natural product compounds using 1D-TOCSY. Trends in Organic Chemistry 22: 99-114. 

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.

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

J  Jorna, J Linde, P Searle, A Jackson, M-E Nielsen, M Nate, N Saxton, F Grewe, M de los Angeles Herrera-Campos, R Spjut, H Wu, B Ho, S Leavitt, T Lumbsch. Species boundaries in the messy middle -- testing the hypothesis of micro-endemism in a recently diverged lineage of coastal fog desert lichen fungi. Submitted March 29, 2021, to Ecology and Evolution, open access to ms, Authorea.  In this study, only Niebla species were assessed employing RAD –sequencing.

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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.

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  Y. Zhang, CY Tan, RW Spjut, JR Fuchs, AD Kinghorn, LH Rakotondraibe. 2020 (Oct). Specialized metabolites of the United States lichen Niebla homalea and their antiproliferative activities. Phytochemistry 180, 112521. In this paper, the type locality for N. homalea is determined to be most likely Point Reyes in Marin County, California, collected by Archibald Menzies in November 1792.  Triterpenoids in Niebla homalea were new, and named nieblastictanes, the name given in reference to the genus name, Niebla, and stictanes, which are related triterpenoids, previously discovered in unrelated South American lichens belonging to the genus Sticta