Lichen Flora of the Greater Sonoran Desert Region:
Book Review

Richard W. Spjut
October 2004, with additional comments, December 2004

Lichen Flora of the Greater Sonoran Desert Region
Vol. 1, edited by Thomas H. Nash III, Bruce D. Ryan, Corinna Gries & Frank Bungartz, 2002, 532 p.
Vol. 2 editors as above and Paul Diederich, 2004. ISBN 0-9716759-1-0, 742 pp.  
Lichens Unlimited, Arizona State University, Thomas-shore, Inc, Dexter, MI

Two morphologically different thalli of Niebla occurring together on rock in Baja California.  Both were found by Spjut to have divaricatic acid.  In the Greater Sonoran Desert Lichen Flora, these would not be differentiated; both would be considered to belong to the same species, Niebla homalea.  In Spjut (1996), however, they are differentiated; the blackish-green thallus on the left is N. podetiaforma, the yellowish-green on the right is Niebla tugida.
This work—proposed to be accomplished in three volumes—provides a much-needed accounting of the lichen flora in southwestern North America.  In the second of two volumes published, Nash reports  ~1300 species in 700 genera have been treated thus far.

My interest in lichen taxonomy developed from collecting samples for antitumor and anti-HIV screening from Baja California and much of the mainland US.  Also, I became interested in developing a lichen flora of Baja California, an area rich in lichen species.  This received encouragement from Phil Rundel and Mason Hale (see letter below from Smithsonian Institution to Dr. Spjut, 1990), while my taxonomic revision of Niebla, which included recognizing a new genus—Vermilacinia, evolved out of frustration in trying to identify material from Baja that I collected during 1985. At that time, I had not considered doing any revision work in lichens.  However, each time I would visit the Smithsonian to use the herbarium to identify my collections, the Curator, Mason Hale, would appear at the herbarium cabinet where I happened to be working; Dr. Hale always seemed to advise me that the genus I was looking at needed study, and that chemistry is critical to identification of the species.

The Greater Sonoran Desert Region is defined by Nash and Gries in Vol. 1 to include not only the Sonoran Desert—as outlined by Forrest Shreve (1936, 1964), but other regions, such as chaparral, coastal sage scrub, and coniferous montane forests in southern Californica, Baja California, and Arizona, the Mojave Desert in California, Arizona and Nevada (NV portion not shaded on map), and subtropical woodland, bushland and scrub forests in Arizona, Sonora, Sinaloa, and Baja California.  The range of the flora extends much further in view of new name combinations by Bowler and Marsh in Niebla for three species found only in the Mediterranean Region.  Perhaps, these volumes should be titled the Greater Sonoran and Mediterranean Lichen Journal.   There are many other new species and combinations reported.  Keys to genera are to be found in both volumes, but those not treated in Volume 1 are indicated to appear in Vol. 2, but as discoveries are made, it has become necessary to provide addenda keys, which appear in Vol. 2.  For example, Mobergia was left out of Vol. 1, but certainly included in Vol. 2-not only in the addendum key, but also in a nice photo on the jacket cover, without acknowledgment of the photographer as done for the photos on the jacket of Vol. 1.  And we are told to expect more addenda in Vol. 3 as the entire flora itself continues to evolve.

Each genus includes a detailed description of its characteristics, references consulted, sometimes a commentary on the taxonomy, sometimes indicating the number of species in the genus, and following this dissertation is a key to the species and a detailed description for each one. Both volumes include occasional black and white photos exemplifying the habit of the lichen species described.  These are fair as might be expected due to lichens being difficult to photograph, but, nevertheless, helpful.  There are also small distribution maps for most species that are helpful.  The second volume includes 24 pages of color plates, four photos to a page, that are mostly very well done, although many are from S. Sharnoff whose outstanding photos nowadays seem to appear in every American lichen book; they are inserted at the genus Niebla, which only seems appropriate, therefore, to review, besides the fact that I am familiar with Niebla taxonomy. 

Included among the color photos are six that they identified as species of Niebla, but none agree with my taxonomy (Spjut 1996); for example, their (1) Niebla ceruchis is Vermilacinia leopardina in Spjut (1996), their Niebla homalea is Niebla podetiaforma in Spjut (1996), their Niebla ceruchoides is Vermilacinia ceruchoides in Spjut (1996), their Niebla polymorpha is Vermilacinia paleoderma in Spjut (1996), their Niebla procera is incorrectly identified even according to their key,  it should have been Niebla combeoides, which Spjut regards as a synonym of Vermilacinia combeoides (Spjut 1995, 1996), and their Niebla robusta is Vermilacinia polymorpha.   It might be further noted here that in the Lichens of North America by Brodo, Sylvia. Sharnoff, and Stephen Sharnoff, that their photo of Niebla homalea is recognized by this author as Niebla cornea, while the remaining species of Niebla depicted are all referable to Vermilacinia in Spjut (1996) without further change in the species epithet.  For additional comments, see Vermilacinia page.

The keys in Vol. 1 recognize both Vermilacinia and Niebla (key by Bruce Ryan), whereas Vermilacinia is not treated in Vol. 2, but included in Niebla by Bowler and Marsh.  Their treatment differs slightly from their previous piece-meal publications in Phytologia and Mycotaxon that included Nash and Riefner as authors (Bowler et al. 1994; Marsh & Nash 1994; Riefner et al. 1995).  Bowler and Marsh now regard Niebla pulchribarbara as a synonym of N. josecuervoi, while Niebla polymorpha appears to be confused with N. robusta; the type for N. polymorpha was not even shown when it was first described, but I did see it during my visit to the lichen herbarium at Arizona State University in April 1996 at which time Janet Marsh and I reviewed many of their Niebla and Vermilacinia specimens.  Maybe it will show up in Vol. 3.  As I recall, Dr. Marsh and I had seemed to recognize Vermialcinia polymorpha as distinct from V. paleoderma, while we both questioned V. tuberculata as being distinct from V. ceruchoides.  So what has happened since?

Bowler and Marsh justify their species at the exclusion of those recognized by Spjut (1996) by indicating that character features are plastic, or that species are highly variable for those species described by Spjut.  Yet, it is surprising that they can justify any species besides N. homalea.  The "plastic" morphology of the ramalinoid genus was recognized long ago under the illegitimate genus homonym Desmazieria where all the morphological variation was then referred to a single species, D. homalea, by Montagne in 1852; the substitute name, Niebla, was provided by Rundel and Bowler (1978) based on discovery of the homonym fact by Follmann (1976), who had thought it was not necessary to create a substitute name.  The general consensus since Montagne (1852) is that there is more than one species in Niebla.  Whether there are just 13 species in one genus (Niebla), or 71 species in two genera (Niebla and Vermilacinia), or whether all of these species could be included under Ramalina, may appear as a matter of opinion; however, whatever approach is taken, it should be consistent.  Bowler is not consistent in his treatment as I will further exemplify.

First, Bowler and Marsh simply state that “there are no generic differences between it [Vermilacinia] and Niebla.”  “Chondroid strands are not present as major structures in the medulla of some species aggregates.”   Bowler's (1981) “aggregates” were species related to N. homalea, N. combeoides and N. flaccescens; the latter two “aggregates” were recognized by Spjut (1995) as belonging to a distinct genus Vermilacina because they lacked isolated chondroid strands in the medulla, had a single-layered cortex, and contained secondary metabolites,
[-]-16 α-hydroxykaurane,  zeorin and other triterpenes not seen in Niebla.  So Bowler and Spjut do agree on the character differences here.  Indeed, Bowler and Marsh distinguish Niebla josecuervoi, N. homalea, and N. isidiaescens from other species, which Spjut recognized as belonging to Vermilacinia, by the presence or absence of “chondroid strands.” Moreover, the Canary Island species of Niebla that Bowler segregated from Ramalina in that region, can only be distinguished from that genus by the chondroid strand character.  The distinction between Vermilacinia and Niebla is further supported by chemistry and molecular data (unpublished).  So why does Bowler and Marsh not recognize Vermilacinia

The problem may date back, at least to Howe (1913) in his revision of Ramalina, if not Nylander (1870), when species of Niebla were treated in Ramalina. Included under Ramalina homalea were thalli with similarly shaped branches that lacked chondroid strands as seen for specimens identified by Howe at the US National Herbarium.  An example is pictured in Hale and Cole's Lichens of California, Plate 6D (1988) that was identified Niebla homalea.  This is an overlooked species that was recognized by Spjut in his unpublished manuscripts of Niebla and Vermilacinia, as Vermilacinia halei (ined.), dating back to Dec. 1987, reviewed by Hale himself in 1987, and supported by numerous annotations of specimens at US, COLO, and at Santa Barbara, however, it was described by  Bowler and Rundel in 1994 (Bowler et al. 1994) under the name of Niebla laevigata.  Had thin-layer-chromatography or other modern chemical separation techniques existed in Howe's time, he probably would have segregated the thalli having chondroid strands as a distinct genus because he indicated this features was almost of generic importance.  The question then is when did Bowler and Rundel first recognize Niebla laevigata (=Vermilaicinia laevigata) in regard to the quoted Rundel and Bowler (1978) statement that “chondroid strands”, which “are not present as major structures in the medulla of some species aggregates, “do not warrant further generic separation in our opinion" as reinstated by Bowler and Marsh in the flora? 

Second, Bowler and Marsh argue that chemistry is not a basis for separating Vermilacinia from Niebla with reference to the diterpene (-)-16α-hydroxykaurane.  Yet, Kashiwandani and Nash in the same flora justify Niebla as distinct from Ramalina by the absence of this diterpene.  So it would seem that chemistry is important to distinguishing genera within the Niebla complex after-all!  In further regard to Ramalina, Kashiwandani and Nash commented that Ramalina can be distinguished from Niebla by the presence of pseudocyphellae; however, the new combination made by Bowler and Marsh, Niebla crispatula, was described in detail by Krog and Østhagen (1980) to have common "marginal psuedocyphellae."  The Mediterranean species of "Niebla" appear intermediate to Vermilacinia, especially in their in secondary metabolites of triterpenes and bougeanic acid with depsidones frequently present as accessory compounds, but are distinguishable as species of Ramalina by the pale pycnidia, as recognized by Kashiwandani and Nash, in contrast to the black pycnidia in Vermilacinia and Niebla.  Thus, the new combinations provided by Bowler and Marsh have only blurred the generic boundaries.  This was discussed in detail by Krog and Østhagen in 1980 when they questioned the generic distinction of Niebla.  Spjut (1995) has since sorted out the problems and clarified the taxonomy by segregating two of the Niebla species “aggregates” into a new genus Vermilacinia.  

Within Niebla sensu Spjut, Bowler and Marsh distinguish N. josecurevoi from N. homalea by chemistry; thus, chemistry is also important in the species taxonomy of Niebla.  Their comparison of Niebla chemistry to that of the Ramalina siliquosa complex should only be applied to Vermilacinia cephalota, V. cerebra, and V. tigrina; it does not apply to Niebla sensu Spjut (1995, 1996)The parallel distinction was discussed in detail by Spjut (1996).  Additionally, Bowler and Marsh treat Niebla homaleoides Spjut as a synonym of N. homalea, whereas Spjut had clearly pointed out that this species is related to N. josecuervoi.  Thus, this revised treatment is not only inconsistent but plainly wrong.

Finally, the interpretation of "Niebla ceruchis" as occurring in North America ignores the basic differences in the taxonomic aggregates that Bowler (1981) himself had recognized, the saxicolous “N. homalea group” and “N combeoides group,” and a corticolous group for which has been given the misapplied name N. ceruchis.  As Spjut (1996) clearly demonstrated, Vermilacinia ceruchis does not occur in North America.  Nonetheless, if Bowler and Marsh interpret this South American terricolous/saxicolous species, which is cleaerly allied to V. combeoides, as encompassing all previously known corticolous species (except N. cephalota), then all species recognized by Bowler and Marsh of the “N. combeoides” and corticolous groups would have to be treated as synonyms of their Niebla ceruchis.  Essentially, this leads to recognizing just one species, Niebla homalea.  This is what Montagne concluded in 1852, and like Bowler and Marsh, Montagne had also commented quite extensively on the variation in the genus.  However, when Bowler and Marsh expand their treatment to species of Niebla in the Canary Islands and Madeira, then to be consistent in the taxonomic treatment, all of the North American species fall under Ramalina homalea.

Bowler and Marsh suggest molecular studies are needed to help resolve the Niebla controversy.  It might be noted that Spjut received a letter in 1995 from the Arizona State University indicating that molecular studies were being done on Niebla at that time, and that there was molecular support for the recognition of Vermilacinia as a distinct genus.  One would think that Bowler, after publishing on the genus over a span of four decades, would have by now obtained molecular support for their taxonomic concepts of Niebla, rather then to blindly draw conclusions that Spjut's species are synonyms of his taxa based on the lack of molecular data.  Moreover, one might expect such data before any further combinations are made.  Was the Bowler and Marsh treatment of Niebla peer reviewed?

One can only hope that the inconsistent treatment of Niebla by Bowler and Marsh is just an isolated case, and that this does not represent the norm for the entire flora.


Bowler, P.A. 1981. Cortical diversity in the Ramalinaceae. Canad.
J. Bot. 59:437-453.

__________ & P. W. Rundel. 1978. Two new lichens (Ramalina)
from Baja California, Mexico. Bryologist 76:211-213.

 __________, 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.

Brodo, I, S.D. Sharnoff & S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven and London.

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

Hale, M. E. & M. Cole. 1988. Lichens of California. University
of California Press, Berkeley.

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.

Marsh, J. & T.H. Nash, III. 1994.  A new lichen species, Niebla
, is described from Baja California, Mexico. Phytologia
76: 458-460.

Montagne, D.M.1852.  Diagnoses phycologicae. Ann. Sci. Nat.
Sér. 3, 18, 302-319.

Nash, T. H.  III, 1995. Arizona State University, Letter to Richard Spjut, Nov 15.

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

Riefner Jr., R. E., P. A. Bowler, J. Marsh & T. H. Nash III. 1995.
Niebla tuberculata (Ramalinaceae): A new lichen from California. Mycotaxon 54: 397-401.

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. Bryologist 75:501-508.

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

Shreve, F. 1936. The transition from desert to chaparral
in Baja California. Madroño 3:257-264.

 _________. 1964. Vegetation of the Sonoran Desert. Pp. 26-126
in Vegetation and flora of the Sonoran Desert by F. Shreve
and I.L. Wiggins, Vol. 1. Stanford University Press, Palo Alto, CA.

Smithsonian Institution. 1990 (Jan. 9).  Letter from the Director of the Natural Museum of Natural History to Dr. Richard Spjut indicating renewal of his appointment as Associate and Collaborator, with particular emphasis on Dr. Spjut's study of the lichens of Baja California.

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.