Philippe Clerc

Lichen chimeras: DNA analysis suggests that one fungus forms two morphotypes

In most lichens, the symbiosis between one fungus (mycobiont) and one photosynthetic partner (photobiont) results in a uniform thallus whose morphology is distinctive for each combination of symbionts. In some lichens, two morphologically different thalli, one containing a green alga, the other a cyanobacterium, are joined together in a chimera called photosymbiodeme. The question whether the same or two different mycobionts are involved in the formation of the different chimera components (morphotypes) is relevant to lichen morphogenesis, physiology, and taxonomy, but has not been answered conclusively to date. We have developed nucleic acid extraction procedures suitable for lichens. Using Southern hybridization and the polymerase chain reaction we demonstrate the genetic near-identity of the mycobionts forming paired morphotypes in two different photosymbiodemes.

Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi.

We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.

A Rapid and Inexpensive Method for the Purification of DNA from Lichens and their Symbionts

A simple DNA extraction method is described, applicable to many different kinds of lichens. The method involves the use of the detergents DTAB and CTAB and yields DNA that can be directly amplified with the polymerase chain reaction or digested with restriction enzymes.

The lichen genus Usnea (Parmeliaceae) in the tropical Andes and the Galapagos: species with a red-orange cortical or subcortical pigmentation

Abstract Usnea species with a red-orange cortical or subcortical pigmentation were studied in the tropical Andes (Venezuela, Colombia, Ecuador, Peru and Bolivia) and the Galapagos Islands. Sixteen species are treated, 14 occurring in the Andes and six in the Galapagos. Usnea crocata, U. grandisora (endemic to the Galapagos), U. rubricornuta and U. subdasaea are newly described. Usnea dorogawensis, U. michauxii, U. subcornuta and U. subrubicunda are new to South America. Tri-terpenoids detected by thin layer chromatography play an important role in the taxonomy of this group of species. Several species were found both in the Andes and the Galapagos, and the diversity of species integrates elements from North America, tropical Africa, Macaronesia and even Asia. This emphasizes the importance of examining large geographic areas to better understand global distribution patterns in this cosmopolitan genus.

NOTES ON THE GENUS USNEA DILL. EX ADANSON

Usnea quercina Bystrek & Gorzynska, based on heterogeneous type material, is lectotypified and becomes a synonym of U. wirthii P. Clerc. Usnea wirthii is new for South America. A distribution map of U. madeirensis Motyka (Syn. U. silesiaca Motyka) in Europe is given. Usnea hesperina Motyka (Syn. U. elongate Motyka, U. schadenbergiana Gopp & Stein, U. subgracilis Vain., U. subplicata (Vain.) Motyka) is new for Africa, Asia and South America. Usnea hirta (L.) F. H. Wigg. (Syn. U. corrugate Motyka, U. foveata Vain., U. leprosa Motyka) is new for Africa. Usnea subscabrosa Nyl. ex Motyka (Syn. U. santae-annae Motyka) is new for South America. The holotype of U. marocana Motyka (= U. mutabilis Stirt.) was found in LBL.

Synopsis of Usnea (lichenized Ascomycetes) from the Azores with additional information on the species in Macaronesia

The genus Usnea is a conspicuous component of the macrolichen vegetation in Macaronesia. Ten species are recognized in the Azorean archipelago: Usnea cornuta Korb., U. esperantiana P. Clerc, U. flammea Stirt., U. geissleriana P. Clerc sp. nov., U. krogiana P. Clerc sp. nov., U. macaronesica P. Clerc sp. nov., U. rubicunda Stirt., U. silesiaca Motyka, U. subflammea P. Clerc sp. nov., and U. subscabrosa Motyka. All these species occur in the Canary Islands as well. Descriptive, chemical, ecological and distributional data for each species are provided. Species that have been recorded once for the Azores but not seen, or that are doubtful or excluded in this work, are briefly discussed.

The saxicolous species of the genus Usnea subgenus Usnea (Parmeliaceae) in Argentina and Uruguay

Abstract Eight primarily saxicolous Usnea subgenus Usnea species are reported from Argentina and Uruguay: U. amblyoclada (Müll. Arg.) Zahlbr. (syn. nov. U. pinnata Räsänen), U. densirostra Motyka, U. durietzii Motyka (syn. nov. U. caespitia Motyka), U. exigua J.M. Rodr. & P. Clerc sp. nov., U. fastuosa (Müll. Arg.) Zahlbr., U. hieronymii Kremp. (syn. nov. U. hieronymii var. adusta Kremp.), U. lutii J.M. Rodr. & P. Clerc sp. nov. and Usnea saxidilatata J.M. Rodr. & P. Clerc sp. nov. are described with morphological, anatomical and chemical data. Their taxonomy and distribution are discussed. A key to the saxicolous species, including those occurring secondarily on rocks (i.e., U. columbiana Motyka, U. cornuta Körb., U. dasaea Stirt. and U. cf. perhispidella J. Steiner) is provided.

Tetramelas thiopolizus comb. nov. with a key to all known species of Tetramelas

The study of the type and additional material of Buellia andicola, B. hypophana and B. reagens has shown that these taxa are conspecific with B. thiopoliza. Buellia thiopoliza is a muscicolous species growing at middle to high altitudes in the mountains of both hemispheres. It is easily recognized by its K+ purple-red yellow pigment mainly concentrated in the hypothecium, and by the presence of xanthones in the thallus and the apothecial tissues. The new combination Tetramelas thiopolizus is proposed. A key to all known Tetramelas species is included. The also muscicolous Buellia hypoleuca is reduced to synonymy with Phaeorrhiza sareptana var. sphaerocarpa.

New species and new records in the genus Usnea ( Parmeliaceae , lichenized Ascomycota) from tropical South America

Usnea is a cosmopolitan genus of lichen-forming Ascomycota ( Parmeliaceae , Lecanorales ). This hyperdiverse genus remains poorly known, especially in tropical regions, and recent efforts have been made to clarify the species concepts and describe the diversity of species. We describe five new species from tropical South America based on morphological and chemical features supported by molecular data from the ITS rDNA, nuLSU, RPB1 and Mcm7 markers. Usnea clerciana is a Galapagos endemic characterized by inflated branches holding elongated tubercles, excavate soralia and/or apothecia. Usnea aranea and U. subaranea share inflated branches with numerous papillae and a loose arachnoid medulla, but differ in the minute and irregular soralia in U. aranea , that are circular and excavate in U. subaranea . Usnea rubriglabrata and U. subglabrata are characterized by inflated branches with excavate soralia, with a reddish cortex pigmentation in U. rubriglabrata that is lacking in U. subglabrata . Usnea aranea , U. rubriglabrata , U. subaranea and U. subglabrata are so far endemic to continental South America; the three former species are closely related and cluster in a highly supported clade, characterized by species distributed in the tropical Andes. New records for the region are provided and U. moreliana is resurrected, corresponding to the valid name for U. rubricornuta .

Multivariate analysis of anatomical characters confirms the differentiation of two morphologically close species, Melanohalea olivacea (L.) O. Blanco et al. and M. septentrionalis (Lynge) O. Blanco et al.

This study investigates how anatomical characters can be used to differentiate two morphologically close species, Melanohalea olivacea (L.) O. Blanco et al. and M. septentrionalis (Lynge) O. Blanco et al. Although the two species are morphologically differentiated, mainly based on the position and shape of pseudocyphellae on the lobes, poorly-developed specimens can be difficult to identify based on morphology alone. For example, in Switzerland, both species are at the south-west limit of their distribution range and most specimens are small and not fully developed. In such cases, anatomical characters are particularly useful in separating the two species. Five anatomical characters were studied: spore length and width; hymenium, subhymenium and hypothecium height. A nested ANOVA showed that variation of spore length was 155 times greater between species than between individuals of the same species, itself 5 times higher than within individuals. In a Principal Component Analysis, despite a substantial variation of the anatomical characters within both species, a significant species differentiation appeared distinctly on the first axis (P < 0·001), which accounted for 62·35% of the total variance, and the type specimens nested within each species. Finally, a Discriminant Linear Analysis assigned 100% of the individuals to their species class, the best predictors to discriminate between the two species being subhymenium height and spore length. These characters proved to be powerful in identifying specimens with a poorly-developed morphology and confirmed the presence of M. olivacea in Switzerland.