Foliicolous lichens are lucky guys, probably the most privileged of all lichenized fungi on this planet. Indeed, they were first dealt with in the masterly monograph of Rolf Santesson in 1952 – a taxonomic approach to fungi that cleared the way towards modern treatments of these organisms. Now their New World representatives are brilliantly revisited by Robert Lücking. Only superlatives and hypersuperlatives apply to this work; it is a Magnum Opus that will remain an outstanding example for many years. This splendid monograph obtained a very much deserved award, namely the De Candolle Prize for best monograph, offered by the Société de Physique et d'Histoire Naturelle de Genève (http://www.unige.ch/sphn/). The prize was awarded before the date of actual publication as advertised on the title page.
Foliicolous lichens are not a natural taxonomic grouping, albeit several genera or families are very well represented, such as Porina, the Gomphillaceae and the Pilocarpaceae (with 26 genera and c. 220 species world-wide). Their unique feature is their habitat: the slippery, harsh and ephemeral habitat formed by the living leaves of the so-called higher plants, in tropical, and warm and wet temperate habitats. Many biologists who may not be interested in long and detailed taxonomic treatments of these inconspicuous species will surely become so on reading the long and detailed chapter on their biogeography and ecology (pp. 58–97). Indeed, it is a remarkable synthesis of the author's observations (incl. experimentation with artificial leaves: see fig. 57) during intensive field work, mainly in Costa Rica, and interpretation of large data sets.
The monograph of foliicolous lichens in the New World by Robert Lücking is indeed based on field experience, all over the area covered, detailed morphological, anatomical and chemical studies, and a wide knowledge of taxonomic and phylogenetic data of all lichens, especially the crustose groups. Further, great attention has been paid to nomenclatural questions, however unpleasant (see for example, the convincing analysis of the status of Ciferri & Tomaselli's generic names, pp. 499–501).
Taxonomic and phylogenetic studies of lichens, and especially tropical taxa, represent a large and fascinating field of research:
(1) The very concept of species in the lichen world is still undecided, especially regarding the status of ‘taxa’ reproducing by vegetative means and dedicated structures most usually organized by the fungus. In a recent phylogenetical study of Roccella in the Galapagos archipelago, Tehler et al. (Reference Tehler, Irestedt, Bungartz and Wedin2009) demonstrated that sorediate populations do not obligatorily represent monophyletic clades. They start their abstract with a strong statement: ‘The species pair concept [in lichenology: sensu Poelt Reference Poelt1970] obscures both intra- and interspecific relationships and should be abandoned, evolutionarily and taxonomically’.
(2) Diversity remains under-estimated, even at high taxonomical level. A nice and unexpected example is provided by the author and co-workers (Lücking et al, Reference Lücking, Lumbsch, Di Stefano, Lizano, Carranza, Bernecker, Chaves and Umaña2008) who discovered and recently described a new lineage of lichenized fungi in Costa Rica, the Eremithallales, with a unique symbiotic lifestyle.
(3) Detailed studies with molecular markers uncover a large number of cryptic species, even in minute examples such as some foliicolous representatives of the genus Porina in Costa Rica, as demonstrated by the recent paper by Baloch & Grube (Reference Baloch and Grube2009). This paper provides strong support for the meticulous use of morphological and anatomical characters for the treatment by Robert Lücking of the species of Porina in his monograph.
(4) Generic delimitation is highly unstable: when large molecular data sets can be gathered on several loci by wide species sampling, and analyzed through modern statistical methods, the genera of entire families can be completely turned upside down. In the Verrucariaceae, Gueidan et al, (Reference Gueidan, Savić, Thüs, Roux, Keller, Tibell, Prieto, Heiðmarsson, Breuss and Orange2009) showed that almost all characters formerly used for generic delimitation are plesiomorphies conserved in most supported clades; thus almost all genera needed a complete revision. It is likely to be the case with the Monoblastiaceae, which comprises typical foliicolous genera and species [such as Caprettia and Trypetheliopsis (= Musaespora)]; none of the characters used for the generic delimitation (ascospore size, conidiomata type, photobiont, etc.) have ever been tested within a phylogenetic framework. The description of the new Caprettia confusa (p. 213) known from only a single locality in Costa Rica is a remarkable example of that situation. Robert Lücking stated that it ‘combines features thus far believed to be typical of Anisomeridium, Caprettia and Musaespora’! Interestingly Nelsen et al. (Reference Nelson, Lücking, Grube, Mbatchou, Muggia, Rivas Plata and Lumbsch2009) (including Robert Lücking, Reference Lücking2009) demonstrate that the Monoblastiaceae forms a strongly supported family within the Dothideomycetes, as already stated by Harris (Reference Harris1995). Such turmoil is also expected in the Roccellaceae in which many genera never gained support in phylogenetic analysis (see the short but conclusive re-assessment of the black, carbonaceous margin as a proper excipulum in Opegrapha; pp. 171–173) and especially in the Pilocarpaceae.
As clearly indicated by the title (‘Foliicolous lichenized fungi’), lichenicolous species are not treated. Identification keys are diverse and adopt several rationales: phylogenetic (so-called ‘natural’) and morphology/anatomy (so-called ‘artificial’). All are very well prepared and quite easy to use; several are quite unusual and very convenient (such as the key for genera and species with verrucae or ridges, or the following one for taxa with a conspicuous prothallus). Species accounts within the corresponding genus paragraph do not appear by alphabetical order, nor by order of sorting out in the key; fortunately the species are referred-to by their epithet and by number of appearance in the account. In the case of large genera with many species, this may not be very convenient. All keys and species accounts are very detailed and full of information and sometimes pleasant to read (pycnidia in Amazonomyces are compared to a sports stadium, which is indeed true; p. 142). The secondary metabolites produced by most species have been examined by TLC, a major improvement in the knowledge of foliicolous taxa, and unexpected results are presented (several species of Mazosia produce psoromic acid).
Taxonomic novelties are well-documented and convincing; they include a new family (Lyrommataceae), four new genera (Baflavia, Brasilicia, Eugeniella and Pseudogyalidea) and no less that 60 new species, 13 new subspecific taxa and 35 new combinations. Major contributions are: (a) the Verrucariales (p. 191 onwards) with a sound delimitation of Psoroglaena (incl. Leucocarpia and Macentina) and Phylloblastia (incl. Pocsia); (b) the species delimitation within Lyromma (pp. 185–186) that includes 3 species with pycnidia and 3 species with perithecia; (c) the treatment of the Lecidea piperis gr. in the recently described Malcolmiella; and last but not least, the treatment of the Pilocarpaceae, with an exceptional generic key (pp. 614–616) and those for the large genera Byssoloma and Fellhanera.
An interesting biological note, of wide interest but which may be overlooked by further workers as it is immersed in such a large monograph, is the observation of a switch of photobiont in Bacidina simplex. Indeed, a new variety is described for populations identical in all details with that species but their photobiont here is a cynanobacterium (var. cyanophila, p. 603). Robert Lücking is aware of the interest of such a photobiont switch, otherwise only known from the Peltigerales, he states ‘this enigmatic lichen is apparently unique ……. most certainly among crustose Lecanorales’.
It is a great pity that the Editor could not publish all species illustrations in colour, or at least to place colour plates at the end of the volume and include them in a CD/DVD attached to it. Volume 3 of the Nordic Lichen Flora (published by the Museum of Evolution, Uppsala University on behalf of Nordic Lichen Society, 219 pp. + CD, 2007) deals with cyanolichens, a large group of species comprizing the most difficult black crusts. For many of those poorly known and seldom collected species, the colour pictures included in that Flora are the only ones available. The New York Botanical Garden Press, acting for the Organization for Flora Neotropica, should have followed that example and thus produced a genuinely modern monograph. A monumental work such as Robert Lücking's reference monograph of neotropical foliicolous lichens clearly deserved it. Anyone who has identified foliicolous lichens is aware of the crucial importance of colours in the identification process, for thallus and vegetative or asexual reproduction organs, as well as for ascocarps. In many cases, especially for several genera such as Badimia, Byssoloma or Fellhanera, subtle hues of colours represent the most accessible and crucial characters. Fortunately, the author is well aware of this shortcoming and made freely available a large set of colour and high-standard photographs at the address http://emuweb.fieldmuseum.org/botany/botanytaxon.php. Any user of this splendid monograph should refer to that source, as well as to several colour plates of species from all over the world at http://emuweb.fieldmuseum.org/botany/rlg/search_rlg.php.
More generally, publication on paper or on-line of high quality photographs of tropical lichen species is now essential, following the pioneer example of Volkmar Wirth in his monumental work on lichens in SW Germany (Wirth Reference Wirth1995) and that of Cáceres (Reference Cáceres and da Silva2007) for crustose and microfoliose epiphytic species from NE Brazil.
The Editor mentioned that the book was published on 26 September 2008. On 10 October, the author posted a detailed note about his achievement to the lichenological community via the Lichen List Server (LICHENS-L@hawaii.edu ). However, dispatching by the Editor faced several difficulties as my order issued by the University of Liège on Oct. 24th 2008 was fullfilled only at the very beginning of April 2009. But doubtless the book is now on the table of all lichenologists world-wide.
The book has been on my table for about a year now, and I am still discovering fascinating information and discussion on several taxa as well as epithets for several species I collected in tropical Africa or Papua New Guinea and that were left aside for many years. But meanwhile, Robert Lücking has managed to publish several major papers on very different topics: (1) a fabulous monograph of the species-rich genus Graphis (Lücking Reference Lücking2009 and Lücking et al, Reference Lücking, Archer and Aptroot2009a); (2) a sound reassessment of the origin of fungi and the divergence date between Ascomycota and Basidiomycota (Lücking et al., Reference Lücking, Lawrey, Sikaroodi, Gillevet, Chaves, Sipman and Bungartz2009b); and (3) the description, with strong phylogenetic support, of a novel, previously unrecognized, highly diverse, exclusively lichenized lineage, of cyanobacteria (Rhizonema: Lücking et al, Reference Lücking, Lawrey, Sikaroodi, Gillevet, Chaves, Sipman and Bungartz2009c). Incredible! No doubt Robert Lücking has reached the highest level of competence for a complete taxonomist: from field work and meticulous morphological descriptions of species to the new frontiers of modern techniques of phylogeny and evolutionary biology, he has demonstrated immense skill and talent. We all look forward towards his further publications.
