Die Flechtengattung Buellia wurde von De Notaris (1846) für Arten mit krustigem Thallus, zweizelligen, gefärbten Ascosporen und schwarzen Apothecien geschaffen. Dieses Gattungskonzept blieb mit wenigen Veränderungen 150 Jahre erhalten. Offensichtlich ist, dass die genannten Merkmale, zufolge denen mehrere hundert Arten unter dem Namen Buellia beschrieben wurden, keine natürliche Artengruppe umfassen. Zur Erstellung eines natürlicheren systematischen Konzepts für die Sammelgattung Buellia werden die corticolen und lignicolen Arten der Subtropen und Tropen erfasst. In diesem Rahmen sind ca. 110 Arten zu finden. Diese werden anhand morphologischer, anatomischer und flechtenchemischer Merkmale sowie ökologischer Ansprüche neu geordnet.

Alle besprochenen Gattungen aus Buellia sensu lato werden den Physciaceae zugerechnet.

The lichen genus Buellia was introduced by De Notaris (1846) for species with crustose thallus, lecideine apothecia and two-celled, coloured ascospores. This genus concept has been conserved with few changes for 150 years. According to these characters several hundred species have been described under the name Buellia. It is obvious that these characters do not form a natural group of species. In the course of deloping a more natural systematic concept for Buellia sensu lato all corticolous and lignicolous species living in the subtropics and tropics are taken into consideration. Within this group about 110 species can be found. Based on morphological characters, lichen substances and ecology a new concept on Buellia is made.

This is the first world monograph of the corticolous species referred to the genus Buellia in tropical and subtropical regions (over 100 taxa), although most of the distribution maps included only refer to neotropical material. The research concludes that the name Buellia can no longer be used for many of these taxa, with most collections now been transferred to 13 other genera: the already well-established genus Amandinea (with 24 species); Baculifera (a new genus with 14 species, half of them new to science); Chrismofulvea (a new genus with four species); Ciposia (a monotypic new genus); Cratiria (a new genus with 13 species); Endohyalina (a new genus with two species); Fluctua (also a monotypic new genus, which is currently known only from the neotropics); Gassicurtia (a genus resurrected here for 15 species, which had been an earlier available name for Buellia sensu lato); Hafellia (with 17 species); Hypoflavia (a new genus with two species, only known from the neotropics); Sculptolumina (a new genus also with two species, but these more widely distributed than the previous one); Stigmatochroma (a new genus with six species) and, finally, the genus Tetramelas, which now includes two species. The name Buellia is only used for some 20 taxa grouped under species of uncertain position and nomina dubia. Yet, in the same section, the author describes and illustrates Buellia rhombispora as a new species, which left me rather confused, since I could not find in the text the characteristic features that define Buellia sensu stricto from the rest. These features, however, are clearly discussed for the 13 genera, under the subheadings of thallus, apothecia, exciple, hypothecium, hymenium, paraphysis, ascospores (including some scanning microphotographs), conidia, ascus types and chemistry, which are, thankfully, summarised and illustrated in five tables. A key to all accepted taxa precedes the individual generic accounts and, within these, it is mostly the new species that are illustrated. A total of 31 species and one variety are described as new, and as many as 72 taxa have been reduced to synonymy, including four Thai species ­ not Malaysian, as stated: Buellia blastenioides Vain. (now Amandinea insperata (Nyl.) H. Mayrhofer & Ropin), Buellia subdives Vain. (now Hafellia subnexa (Nyl.) Marbach, a new name, not a new combination, since the basionym is illegitimate), Buellia pleiophoroides var. meiospermoides Vain. (now Stigmatochroma adaucta (Malme) Marbach), an earlier name than the basionym, but without priority outside its rank, see ICBN Art. 11.2, and Buellia stramineoatra (now Amandinea melaxanthella (Nyl.) Marbach). I mention these taxa because I have myself studied their types, although from Turku herbarium, not Copenhagen, and had the opportunity to compare my notes with the descriptions in the monograph. It would never have occurred to me that the four taxa were anything but Buellia. Luckily, it appears that all these genera still belong to the Physciaceae. I was also pondering whether a similar fate awaits the genus Rinodina with its distinct and varied ascospore morphology.

On a critical note, the English abstract included is too limited, since the features used to delimit the newly-introduced genera are not mentioned. Therefore, African and Asian lichenologists working in tropical and subtropical regions will have to struggle to understand the German text or the synoptic Spanish keys and descriptions, the latter incorporated into a 28- page appendix. This is a real pity since, when reading the Spanish translation, I got the impression that it was prepared from an English original, by some of the odd turns of phrase encountered. Also, the illustrations (163 ink-drawings of the taxa and their distribution in the neotropics) are rather basic for a monograph of this scope; photographs, at least illustrating the major features characterising the different genera, would have been most welcome for the less-initiated. Finally, by its presentation and general layout, this publication appeals mostly to professional lichenologists. However, I foresee that it will be widely consulted ­ and beyond those working in the tropics ­ so it is a pity that it is only available in paperback and not in a more durable format.

B. Aguirre-Hudson

Bibliography of Systematic Mycology and Index of Fungi

Buellia, in the broadest sense, is one of the most speciose genera of crustose lichen-fungi with over 400 accepted species. In recent years, some genera have been segregated primarily on the basis of differences in the conidia (e.g. Amandinea) or ascospores (e.g. Hafellia). However, there has been no overall study of the genus attempting to revise generic concepts, although Nordin has since addressed those referred to Diplotomma. Here, Marbach examines the tropical and subtropical species on bark and wood. This is the first time many of the taxa have been critically studied since their original desriptions, and while surprises were to be expected, the extent of the proposals for changes at the generic level are staggering. Not only are nine new generic names introduced (Baculifera, Chrismofulvea, Ciposia, Cratiria, Endohyalina, Fluctua, Hypoflavia, Sculptolumina, and Stigmatochroma), two genera are resurrected (Gassicurtia and Tetramelas). Naturally, Amandinea and Hafellia are acceptedbut Buellia s. str. and Diplotomna s. str. species do not occur on bark or wood in the tropics or subtropics. The author presumes that the proposal to conserve Buellia with the saxicolous B. aethalea made in 1999 will be accepted. Marbach's new generic concepts are based on a wide range of characters, tabulated on pp. 42-44; these include thallus chemistry, ascospore structure, conidium-type, hymenium inspersion, paraphyses types, apothecial pruinosity, and exciple structure and pigmentation. Not all mycologists would regard all the differences documented here as appropriate to segregate genera, and it is inevitable that much debate will now ensue, some authors accepting particular decisions but not all. It is unfortunate that the study did not include any molecular data as in the early twenty-first century that is increasingly a prerequisite for the justification of major changes in generic concepts. Further, it will be of interest to see how the generic concepts hold when applied to temperate and boreal taxa; this is a refreshing situation to be worked with as it is more usual to struggle to'fit' tropical taxa into concepts based on temperate taxa.

Independently from the issue of generic concepts, Marbach has made an amazing contribution to improving species concepts and unravelling species names from the past. Thirty-one species new to science are described, and numerous species are relegated to synonymy for the first time. For eachspecies, detailed descriptions are provided, and in many cases line drawings of the key microscopical features and distribution maps are included. There are a few photomicrographs and scanning electron micrographs in the introductory sections, but no habit illustrations at all. Keys are provided in both German and Esperanto (a practice of doubtful value), and short diagnoses in the latter language are also to be found. There are notes on pertinent generic names, and also excluded species (some with descriptions and drawings).

This is without doubt a landmark publication which cannot be ignored by any workers on buellioid lichens, who must now take a position on which segregates to accept and which to ignore - while awaiting molecular data.

Mycotaxon vol. 84, Jan. 2003