Furthermore the author presents a key to the taxa covered by this study. A statistical analysis was conducted to verify the significance of the spore characters for identification and completes this study.

As a result of this revision, the following taxa are now part of the C. saxicola group: Caloplaca arnoldii (Wedd.) Zahlbr.; C. arnoldii subsp. clauzadeana Gaya; C. arnoldii subsp. nana Gaya; C. arnoldii subsp. obliterata Gaya; C. arnoldiiconfusa Gaya & Nav.-Ros.; C. biatorina (A. Massal.) J. Steiner; C. decipiens (Arnold) Blomb. & Forssell; C. pseudofulgensia Gaya & Nav.-Ros.; C. pusilla (A. Massal.) Zahlbr.; C. rouxii Gaya, Nav.-Ros. & Llimona; C. saxicola (Hoffm.) Nordin; and C. schistidii (Anzi) Zahlbr.

This contribution to the Bibliotheca Lichenologica series focuses on a widespread group of Calopaca species with placodioid thallus. The taxonomy of the genus Caloplaca is very complex and this revision tackles with a group of morphologically variable taxa. The book includes a revision of the species occurring in the Northern Hemisphere and is based on the morphological examination of ca. 650 specimens and the relevant type specimens. The author accepts nine species in the group and five subspecies. The number of accepted subspecies is unusual for lichenological treatments; the basic concept for the use of the subspecific rank is not discussed in detail here. All accepted taxa are described morphologically in detail and compared with similar taxa. Unfortunately, the secondary chemistry is not treated, but is said to be "not a good diagnostic character" in the group. Synonymy and nomenclature are discussed in detail and the discussion of each species follows modern standards. The citation of examined specimens is given in some length. In general, the layout of the book is not economic regarding space. There are numerous half-empty pages and the text could have been condensed in 150 pages without problems. This is not a criticism towards the author, but should be considered by the editors, especially given the relatively high costs of the issue. The literature is well discussed and the list of references includes most relevant literature. All species are also well illustrated with detailed drawings of anatomical details and habit photographs. This is certainly a very useful contribution to the taxonomy of this difficult group. I am curious to see molecular data confirming the taxonomic concepts of the author.

H.T. LUMBSCH, Chicago

This is a technical revision of a small group of conspicuous but taxonomically obscure lichens, based on morphological and anatomical studies. Nine species (one of which has four subspecies) are accepted within the aggregate, with a further four treated in detail but excluded from the group. The study has clearly been meticulous, with around 650 specimens examined. Highly detailed accounts of the constituent taxa are presented, with critical components such as ascospore and spore septum dimensions being subjected to rigorous statistical analysis. The descriptions are models of their type. However, the technical terminology is (by some way) unnecessarily complex, leading to frequent consultation of the definitions section in the introductory part. I for one was lost in reading phrases such as ‘Parathecium ... with hyphae radially arranged, scleroprosoplectenchymatous of scleroplectenchymatous type B’.

I did feel that something was missing from this work. There is no formal definition of the Caloplaca saxicola ‘group’ itself. Its modern delimitation seems to be based primarily on molecular data (with references to one published paper and a further one in preparation). However, there is hardly a mention of these works apart from in the two-page introduction, no indication as to the close relatives and no linkages to the species and infraspecific taxa accounts. Why were the subspecies of C. arnoldii treated at this level and not given species status, for example? It is understandable that the publishers of phylogenetics research do not wish to present long lists of specimens examined, but the (presumably well-heeled) purchasers of this book deserve to see the full story. That apart, this small monograph will be a valuable technical resource, for the limited and still-contracting world community of systematic lichenologists.

Paul Cannon

Bibliography of Systematic Mycology, 12(9), April 2010

Though the genus Caloplaca was widely studied by several authors, some groups of it was still poorly understood when the author started to work on it. The Caloplaca saxicola group was revised in the Northern Hemisphere. Most of the species of this group have Holarctic distribution in xeric habitats on calcareous substrates. The traditional (more artificial, but practical) taxonomic treatment within Gasparrinia with the saxicolous, placodioid, lobed thalli containing anthraquinones was reconsidered according to the recent molecular phylogenetic results, and a restricted, more homogeneous, more natural species group was re-circumscribed. Macroscopical and microscopical investigations were carried out on 650 specimens of more than 20 herbaria, including the author’s own collections. The main characters involved in the study were thallus shape, surface, microscopical features of the layers, reproductive structures, chemistry (colour reactions only), ecology, and distribution.

As a result nine species (11 taxa) are kept in C. saxicola group with the description of two new species (C. arnoldiiconfusa Gaya et Nav.-Ros., C. pseudofulgensia Gaya et Nav.-Ros.) and two subspecies (C. arnoldii subsp. clauzadeana Gaya and C. arnoldii subsp. nana Gaya). The new name C. rouxii Gaya, Nav.-Ros. et Llimona was introduced and the C. arnoldii subsp. obliterata Gaya new combination was made. Four taxa were excluded (C. cirrochroa, C. saxicola subsp. laceratula, C. obliterans, C. proteus). Three species and a species group are closely related to the C. saxicola group. Three sorediate species with lobes are also characterised. The species and infraspecific taxa are included in the detailed key provided. The statistical analysis of the variables is found in the discussion.

Colour photographs and excellent drawings of ascospores, and details of thallus and fruit-bodies are illustrating the treated taxa.

As a whole it is a nice contribution to the knowledge of the C. saxicola group and related taxa.

E. FARKAS

Acta Botanica Hungarica 53 (3-4), 2011, p. 443