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