Taxonomic and Phylogenetic Reassessment of Pyrgidium (Mycocaliciales) and Investigation of Ascospore Morphology.

Mycocaliciales comprise non-lichenized either saprotrophic or lichenicolous fungi which occur in temperate and tropical regions. The mazaediate, saprotrophic and monospecific genus, Pyrgidium, is currently assigned to this order, yet the phylogenetic placement of the genus has remained uncertain due to the absence of molecular data. In order to investigate the systematic position of Pyrgidium, two specimens collected in Brazil and Thailand, respectively, were used to generate mtSSU, SSU, LSU and ITS sequences. However, given that most other representatives of this order only have LSU and ITS sequences available, the phylogenetic reconstruction was limited to these two markers. The phylogenetic analyses confirmed placement of the genus within Mycocaliciales, the genus possessing a sister group relationship with the lichenicolous genus Sphinctrina. Detailed morphological descriptions and illustrations are provided, including those for type specimens of the various synonyms subsumed under the hitherto only accepted species, Pyrgidium montellicum (Beltr.) Tibell. The ascospore morphology was investigated using compound and scanning electronic microscopy (SEM). Principal component analysis (PCA) was performed for the ascospore size using PC-ORD 7. The molecular data and re-examination of the type specimens support the monospecific nature of this genus.

The Diversity of Lichenized Trentepohlioid Algal (Ulvophyceae) Communities is Driven by Fungal Taxonomy and Ecological Factors.

Trentepohliales are a group of both free-living and lichenized algae, with most diversity occurring in tropical regions. Recent studies showed that the abundance of lichens with a trentepohlioid photobiont has been increasing in temperate habitats, probably because of global warming, which makes them an interesting study case. A detailed molecular study of the diversity of lichenized Trentepohliales, epiphytic as well as epilithic, was performed in three forests of north-western Europe. Additional samples of lichens of the Arthoniales order (associating essentially with a trentepohlioid photobiont) from other European regions and from other continents were also sequenced. A total of 195 algal sequences were obtained. Phylogenetic analyses with rbcL and ITS loci were performed and associations between phylogenetic distances of photobionts and ecological factors (substratum, climate or Wirth indices, mycobiont taxonomy, and geographic location) were tested by variation partitioning and phylogenetic signal analyses. The high number of rbcL algal haplotypes found in some lichens or on different substrata revealed that the Trentepohliales diversity in extratropical regions was underestimated. The phylogenetic patterns showed selectivity of some photobionts in their fungal partner choice and vice-versa, while others were linked with several haplotypes. Photobionts seemed to be less selective than mycobionts. The main factors influencing lichenized algal community were climate and mycobiont species. Coevolution between mycobionts and photobionts as well as switching between free living and lichenized lifestyles appeared to drive the evolution of Trentepohliales and might explain the high cryptic diversity observed, which might be changing in some regions due to climate change.

Mendogiadiffusa sp. nov. and an updated key to the species of Mendogia (Myriangiaceae, Dothideomycetes).

BACKGROUND: Mendogia belongs to Dothideomycetes and its members are epiphytic on living bamboo culms or palms and distributed in tropical regions. Currently, the genus comprises seven species. Another collection resembling Mendogia was collected from the leaves of Fagales sp. in Thailand. Morphological characteristics and multilocus phylogenetic analyses, using ITS, LSU and SSU sequences, showed that the fungus is new to science, described herein as Mendogiadiffusa. Mendogiadiffusa is characterised by apothecial ascostromata, a carbonised epithecium, dark brown setae on the ascostromatal surface, hyaline paraphysoids, ovoid to clavate asci and oblong to elliptical, muriform ascospores. The fungus has a dark pigmented surface and is occasionally facultatively associated with patches of green algae, but not actually lichenised. Instead, the fungus penetrates the upper leaf surface, forming dark pigmented isodiametric cells below the epidermis. NEW INFORMATION: Re-examination of specimens of M.chiangraiensis, M.macrostroma and M.yunnanensis revealed the absence of algal associations. The status of Mendogiaphilippinensis (= M.calami) and M.bambusina (= Uleopeltisbambusina) was established, based on morphological comparisons and previous studies. Comprehensive morphological descriptions with phylogenetic analyses support M.diffusa as a novel species in Myriangiaceae. An updated key to the known species of the genus is also provided.

The Evolution of Life Modes in Stictidaceae, with Three Novel Taxa.

Ostropales sensu lato is a large group comprising both lichenized and non-lichenized fungi, with several lineages expressing optional lichenization where individuals of the same fungal species exhibit either saprotrophic or lichenized lifestyles depending on the substrate (bark or wood). Greatly variable phenotypic characteristics and large-scale phylogenies have led to frequent changes in the taxonomic circumscription of this order. Ostropales sensu lato is currently split into Graphidales, Gyalectales, Odontotrematales, Ostropales sensu stricto, and Thelenellales. Ostropales sensu stricto is now confined to the family Stictidaceae, which includes a large number of species that are poorly known, since they usually have small fruiting bodies that are rarely collected, and thus, their taxonomy remains partly unresolved. Here, we introduce a new genus Ostropomyces to accommodate a novel lineage related to Ostropa, which is composed of two new species, as well as a new species of Sphaeropezia, S. shangrilaensis. Maximum likelihood and Bayesian inference analyses of mitochondrial small subunit spacers (mtSSU), large subunit nuclear rDNA (LSU), and internal transcribed spacers (ITS) sequence data, together with phenotypic data documented by detailed morphological and anatomical analyses, support the taxonomic affinity of the new taxa in Stictidaceae. Ancestral character state analysis did not resolve the ancestral nutritional status of Stictidaceae with confidence using Bayes traits, but a saprotrophic ancestor was indicated as most likely in a Bayesian binary Markov Chain Monte Carlo sampling (MCMC) approach. Frequent switching in nutritional modes between lineages suggests that lifestyle transition played an important role in the evolution of this family.

Draft Genome Sequence and Annotation of the Lichen-Forming Fungus Arthonia radiata.

We report here the draft de novo genome assembly, transcriptome assembly, and annotation of the lichen-forming fungus Arthonia radiata (Pers.) Ach., the type species for Arthoniomycetes, a class of lichen-forming, lichenicolous, and saprobic Ascomycota. The genome was assembled using overlapping paired-end and mate pair libraries and sequenced on an Illumina HiSeq 2500 instrument.

Intrathalline Metabolite Profiles in the Lichen Argopsis friesiana Shape Gastropod Grazing Patterns.

Lichen-gastropod interactions generally focus on the potential deterrent or toxic role of secondary metabolites. To better understand lichen-gastropod interactions, a controlled feeding experiment was designed to identify the parts of the lichen Argopsis friesiana consumed by the Subantarctic land snail Notodiscus hookeri. Besides profiling secondary metabolites in various lichen parts (apothecia, cephalodia, phyllocladia and fungal axis of the pseudopodetium), we investigated potentially beneficial resources that snails can utilize from the lichen (carbohydrates, amino acids, fatty acids, polysaccharides and total nitrogen). Notodiscus hookeri preferred cephalodia and algal layers, which had high contents of carbohydrates, nitrogen, or both. Apothecia were avoided, perhaps due to their low contents of sugars and polyols. Although pseudopodetia were characterized by high content of arabitol, they were also rich in medullary secondary compounds, which may explain why they were not consumed. Thus, the balance between nutrients (particularly nitrogen and polyols) and secondary metabolites appears to play a key role in the feeding preferences of this snail.

Photobiont switching causes changes in the reproduction strategy and phenotypic dimorphism in the Arthoniomycetes.

Phylogenetic analyses using mtSSU and nuITS sequences of Buellia violaceofusca (previously placed in Lecanoromycetes), a sterile, sorediate lichen having a trebouxioid photobiont, surprisingly prove that the species is conspecific with Lecanographa amylacea (Arthoniomycetes), a fertile, esorediate species with a trentepohlioid photobiont. These results suggest that L. amylacea and B. violaceofusca are photomorphs of the same mycobiont species, which, depending on the photobiont type, changes the morphology and the reproduction strategy. This is the first example of a lichenized fungus that can select between Trebouxia (Trebouxiophyceae) and trentepohlioid (Ulvophyceae) photobionts. Trebouxia photobionts from the sorediate morphotype belong to at least three different phylogenetic clades, and the results suggest that Lecanographa amylacea can capture the photobiont of other lichens such as Chrysothrix candelaris to form the sorediate morphotype. Phylogenetic analyses based on rbcL DNA data suggest that the trentepohlioid photobiont of L. amylacea is closely related to Trentepohlia isolated from fruticose lichens. The flexibility in the photobiont choice enables L. amylacea to use a larger range of tree hosts. This strategy helps the lichen to withstand changes of environmental conditions, to widen its distribution range and to increase its population size, which is particularly important for the survival of this rare species.

Scientific user requirements for a herbarium data portal.

The digitization of herbaria and their online access will greatly facilitate access to plant collections around the world. This will improve the efficiency of taxonomy and help reduce inequalities between scientists. The Botanic Garden Meise, Belgium, is currently digitizing 1.2 million specimens including label data. In this paper we describe the user requirements analysis conducted for a new herbarium web portal. The aim was to identify the required functionality, but also to assist in the prioritization of software development and data acquisition. The Garden conducted the analysis in cooperation with Clockwork, the digital engagement agency of Ordina. Using a series of interactive interviews, potential users were consulted from universities, research institutions, science-policy initiatives and the Botanic Garden Meise. Although digital herbarium data have many potential stakeholders, we focused on the needs of taxonomists, ecologists and historians, who are currently the primary users of the Meise herbarium data portal. The three categories of user have similar needs, all wanted as much specimen data as possible, and for those data, to be interlinked with other digital resources within and outside the Garden. Many users wanted an interactive system that they could comment on, or correct online, particularly if such corrections and annotations could be used to rank the reliability of data. Many requirements depend on the quality of the digitized data associated with each specimen. The essential data fields are the taxonomic name; geographic location; country; collection date; collector name and collection number. Also all researchers valued linkage between biodiversity literature and specimens. Nevertheless, to verify digitized data the researchers still want access to high quality images, even if fully transcribed label information is provided. The only major point of disagreement is the level of access users should have and what they should be allowed to do with the data and images. Not all of the user requirements are feasible given the current technical and regulatory landscape, however, the potential of these suggestions is discussed. Currently, there is no off-the-shelf solution to satisfy all these user requirements, but the intention of this paper is to guide other herbaria who are prioritising their investment in digitization and online web functionality.

Circumscription and phylogeny of the Lepidostromatales (lichenized Basidiomycota) following discovery of new species from China and Africa.

Based on an exhaustive sampling of all known Lepidostromatales, a lineage of clavarioid lichen-forming basidiomycetes, we assess (i) the phylogenetic affinities of the six Chinese species currently accommodated in Multiclavula (Cantharellales) based on inferences from the 18S and 28S subunits of the nuclear ribosomal DNA repeat and (ii) the phylogenetic structure among Chinese populations of Lepidostromatales, based on the nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS]) regions. Multiclavula fossicola and M. sinensis belong to the Lepidostromatales and are transferred to Sulzbacheromyces. Chinese reports of M. clara and M. vernalis belong to species of Lepidostromatales, and specimens identified as M. mucida belong to the nonlichenized genus Clavaria. Hence, evidence of Multiclavula occurring in China is lacking. Similarly, L. calocerum is excluded from the Chinese flora. The recently described L. asianum should be regarded as conspecific with S. sinensis. Three new species of Sulzbacheromyces are described: S. bicolor and S. yunnanensis from China and S. miomboensis from the Democratic Republic of Congo. Consequently, Sulzbacheromyces is new to Asia and Africa. A worldwide key to the species of Lepidostromatales is provided.

Contribution to the phylogeny and taxonomy of the genus Taeniolella, with a focus on lichenicolous taxa.

Taeniolella is a genus of asexual ascomycetes with saprophytic, endophytic, and lichenicolous life styles. A phylogeny of representative species is presented, with a focus on lichenicolous taxa. We obtained mtSSU and nuLSU sequence data from culture isolates of Taeniolella and from freshly collected specimens of other taxa. Taeniolella is recovered as strongly polyphyletic. The type species, Taeniolella exilis, is placed in Kirschsteiniotheliaceae within Dothideomycetes. Other saprophytic/endophytic Taeniolella species previously assigned to Sordariomycetes based on sequences were found to represent either contaminants or species that cannot be assigned to Taeniolella for morphological reasons. Lichenicolous species are restricted to Asterotexiales (Dothideomycetes) where the sequenced species of Taeniolella do not form a monophyletic group, but are related to species of Buelliella s. lat., Karschia, Labrocarpon, Melaspilea s. lat., and Stictographa. Molecular data are, however, not sufficient to reallocate the lichenicolous Taeniolella species to other genera so far. Anamorph-teleomorph relationships between these taxa and lichenicolous Taeniolella are discussed but could not be demonstrated. The type of Buelliella is placed in Asterotexiales, and the genus recovered as polyphyletic. Three new lichenicolous Taeniolella species are described, Taeniolella hawksworthiana, Taeniolella pyrenulae and Taeniolella toruloides. Taeniolella rudis is transferred to Sterigmatobotrys.

Bacterial and eukaryotic biodiversity patterns in terrestrial and aquatic habitats in the Sør Rondane Mountains, Dronning Maud Land, East Antarctica.

The bacterial and microeukaryotic biodiversity were studied using pyrosequencing analysis on a 454 GS FLX+ platform of partial SSU rRNA genes in terrestrial and aquatic habitats of the Sør Rondane Mountains, including soils, on mosses, endolithic communities, cryoconite holes and supraglacial and subglacial meltwater lenses. This inventory was complemented with Denaturing Gradient Gel Electrophoresis targeting Chlorophyta and Cyanobacteria. OTUs belonging to the Rotifera, Chlorophyta, Tardigrada, Ciliophora, Cercozoa, Fungi, Bryophyta, Bacillariophyta, Collembola and Nematoda were present with a relative abundance of at least 0.1% in the eukaryotic communities. Cyanobacteria, Proteobacteria, Bacteroidetes, Acidobacteria, FBP and Actinobacteria were the most abundant bacterial phyla. Multivariate analyses of the pyrosequencing data revealed a general lack of differentiation of both eukaryotes and prokaryotes according to habitat type. However, the bacterial community structure in the aquatic habitats was dominated by the filamentous cyanobacteria Leptolyngbya and appeared to be significantly different compared with those in dry soils, on mosses, and in endolithic habitats. A striking feature in all datasets was the detection of a relatively large amount of sequences new to science, which underscores the need for additional biodiversity assessments in Antarctic inland locations.

Phylogenetic placement of the lichenicolous, anamorphic genus Lichenodiplis and its connection to Muellerella-like teleomorphs.

Lichenicolous fungi are a specialized group of taxa which inhabit lichens and develop diverse degrees of specificity and parasitic behaviour towards their hosts. They are recognized only by their phenotypic symptoms and sexual or asexual spore-producing structures on the lichen thalli. Only recently, molecular data and culture dependent approaches have helped in uncovering the species diversity and in verifying the phylogenetic position and anamorph-teleomorph relationships of some taxa. Here, we studied the phylogenetic placement of representative taxa of two lichenicolous genera, the coelomycete Lichenodiplis and the ascomycete Muellerella. We obtained molecular data for three nuclear and mitochondrial loci (28S, 18S, and 16S), both from fresh collected specimens and culture isolates. Our multilocus phylogeny places Lichenodiplis and Muellerella samples in one monophyletic, fully supported clade, sister to Epibryon (Epibryaceae) in Chaetothyriales (Eurotiomycetes). Morphological analyses of axenically cultured fungi show the formation of conidiomata and conidiospores in both Lichenodiplis and Muellerella isolates. We suggest that the species Lichenodiplis lecanorae and Muellerella atricola represent, respectively, the anamorphic and teleomorphic stages of the same fungus and discuss their relationships with the other fungal families in Chaetothyriomycetidae.

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.

Culturable bacterial diversity at the Princess Elisabeth Station (Utsteinen, Sør Rondane Mountains, East Antarctica) harbours many new taxa.

We studied the culturable heterotrophic bacterial diversity present at the site of the new Princess Elisabeth Station at Utsteinen (Dronning Maud Land, East Antarctica) before construction. About 800 isolates were picked from two terrestrial microbial mat samples after incubation on several growth media at different temperatures. They were grouped using rep-PCR fingerprinting and partial 16S rRNA gene sequencing. Phylogenetic analysis of the complete 16S rRNA gene sequences of 93 representatives showed that the isolates belonged to five major phyla: Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes and Deinococcus-Thermus. Isolates related to the genus Arthrobacter were the most prevalent whereas the genera Hymenobacter, Deinococcus, Cryobacterium and Sphingomonas were also recovered in high numbers in both samples. A total of 35 different genera were found, the majority of which has previously been reported from Antarctica. For the genera Aeromicrobium, Aurantimonas, Rothia, Subtercola, Tessaracoccus and Xylophilus, this is the first report in Antarctica. In addition, numerous potential new species and new genera were recovered; many of them currently restricted to Antarctica, particularly in the phyla Bacteroidetes and Deinococcus-Thermus.

A two-gene phylogeny shows the lichen genus Niebla (Lecanorales) is endemic to the New World and does not occur in Macaronesia nor in the Mediterranean basin.

The generic segregates of the widespread fruticose genus Ramalina (mostly based on empirical data on morphology, cortex anatomy and secondary metabolites) are studied using maximum parsimony, maximum likelihood and Bayesian analyses of nuclear LSU and ITS sequences. The species examined include the three species aggregates within Niebla from the western coasts of North America, all species except one assumed to belong to the same genus from Macaronesia and the Mediterranean basin, the type species of Dievernia and Ramalina, and representatives of the genus Fistulariella. The genus Niebla is strongly supported when restricted to species from the New World, and all species referred to it from Macaronesia and the Mediterranean basin belong to Ramalina (R. bourgeana, R. crispatula, R. cupularis, R. hamulosa, R. portosantana, R. rosacea, R. subwebbiana and R. webbii). No support is found for the genera Dievernia and Fistulariella. The internal topology of the large genus Ramalina is unresolved and needs further studies.

Towards a new classification of the Arthoniales (Ascomycota) based on a three-gene phylogeny focussing on the genus Opegrapha.

A multi-locus phylogenetic study of the order Arthoniales is presented here using the nuclear ribosomal large subunit (nuLSU), the second largest subunit of RNA polymerase II (RPB2) and the mitochondrial ribosomal small subunit (mtSSU). These genes were sequenced from 43 specimens or culture isolates representing 33 species from this order, 16 of which were from the second largest genus, Opegrapha. With the inclusion of sequences from GenBank, ten genera and 35 species are included in this study, representing about 18% of the genera and ca 3% of the species of this order. Our study revealed the homoplastic nature of morphological characters traditionally used to circumscribe genera within the Arthoniales, such as exciple carbonization and ascomatal structure. The genus Opegrapha appears polyphyletic, species of that genus being nested in all the major clades identified within Arthoniales. The transfer of O. atra and O. calcarea to the genus Arthonia will allow this genus and family Arthoniaceae to be recognized as monophyletic. The genus Enterographa was also found to be polyphyletic. Therefore, the following new combinations are needed: Arthonia calcarea (basionym: O. calcarea), and O. anguinella (basionym: Stigmatidium anguinellum); and the use of the names A. atra and Enterographa zonata are proposed here. The simultaneous use of a mitochondrial gene and two nuclear genes led to the detection of what seems to be a case of introgression of a mitochondrion from one species to another (mitochondrion capture; cytoplasmic gene flow) resulting from hybridization.

The Ascomycota tree of life: a phylum-wide phylogeny clarifies the origin and evolution of fundamental reproductive and ecological traits.

We present a 6-gene, 420-species maximum-likelihood phylogeny of Ascomycota, the largest phylum of Fungi. This analysis is the most taxonomically complete to date with species sampled from all 15 currently circumscribed classes. A number of superclass-level nodes that have previously evaded resolution and were unnamed in classifications of the Fungi are resolved for the first time. Based on the 6-gene phylogeny we conducted a phylogenetic informativeness analysis of all 6 genes and a series of ancestral character state reconstructions that focused on morphology of sporocarps, ascus dehiscence, and evolution of nutritional modes and ecologies. A gene-by-gene assessment of phylogenetic informativeness yielded higher levels of informativeness for protein genes (RPB1, RPB2, and TEF1) as compared with the ribosomal genes, which have been the standard bearer in fungal systematics. Our reconstruction of sporocarp characters is consistent with 2 origins for multicellular sexual reproductive structures in Ascomycota, once in the common ancestor of Pezizomycotina and once in the common ancestor of Neolectomycetes. This first report of dual origins of ascomycete sporocarps highlights the complicated nature of assessing homology of morphological traits across Fungi. Furthermore, ancestral reconstruction supports an open sporocarp with an exposed hymenium (apothecium) as the primitive morphology for Pezizomycotina with multiple derivations of the partially (perithecia) or completely enclosed (cleistothecia) sporocarps. Ascus dehiscence is most informative at the class level within Pezizomycotina with most superclass nodes reconstructed equivocally. Character-state reconstructions support a terrestrial, saprobic ecology as ancestral. In contrast to previous studies, these analyses support multiple origins of lichenization events with the loss of lichenization as less frequent and limited to terminal, closely related species.

A new lineage of lichenized basidiomycetes inferred from a two-gene phylogeny: The Lepidostromataceae with three species from the tropics.

The lichen habit has apparently evolved independently in at least five major clades of mushroom-forming basidiomycetes (Agaricomycetes). Tracing the origin of lichenization in these groups depends on a clearer understanding of the phylogenetic relationships of basidiolichens to other fungi. We describe here a new family of basidiolichens made up of tropical, soil-inhabiting fungi that form lichenized, scale-like squamules and erect, coral-like fruiting structures. These structures are common to two basidiolichen genera, Multiclavula and Lepidostroma. Molecular studies have confirmed the phylogenetic position of Multiclavula species in the Cantharellales, but Lepidostroma species have never been sequenced. We obtained nuclear small and large subunit ribosomal sequences from specimens of L. calocerum collected in Costa Rica and Mexico and also from specimens of two Multiclavula spp. recently described from Rwanda. The phylogenetic placement of these fungi within the Agaricomycetes was investigated using likelihood and Bayesian analyses. Our results indicate that L. calocerum and the Rwandan species form a natural group unrelated to Multiclavula and sister to the Atheliales, members of which are neither lichen-forming nor clavarioid. The independent evolution of morphologically similar forms in so many groups of basidiomycetes is a remarkable example of convergence, indicating similar pathways to lichenization in these fungi.

Switchable reflector in the Panamanian tortoise beetle Charidotella egregia (Chrysomelidae: Cassidinae).

The tortoise beetle Charidotella egregia is able to modify the structural color of its cuticle reversibly, when disturbed by stressful external events. After field observations, measurements of the optical properties in the two main stable color states and scanning electron microscope and transmission electron microscope investigations, a physical mechanism is proposed to explain the color switching of this insect. It is shown that the gold coloration displayed by animals at rest arises from a chirped multilayer reflector maintained in a perfect coherent state by the presence of humidity in the porous patches within each layer, while the red color displayed by disturbed animals results from the destruction of this reflector by the expulsion of the liquid from the porous patches, turning the multilayer into a translucent slab that leaves an unobstructed view of the deeper-lying, pigmented red substrate. This mechanism not only explains the change of hue but also the change of scattering mode from specular to diffuse. Quantitative modeling is developed in support of this analysis.

Phylogenetic diversity of lichen-associated homobasidiomycetes.

The vast majority of lichenicolous fungi are relatively host-specific, nonvirulent ascomycetes and heterobasidiomycetes. A few known lichenicolous homobasidiomycetes (mushroom-forming fungi) generally exhibit broad host ecologies and in some cases, high virulence. Many produce conspicuous sclerotia or bulbils, thought to be adaptive in dispersal and survival. To more clearly understand the evolution of these atypical behaviors in lichenicolous basidiomycetes, we isolated or acquired specimens or cultures of 23 lichenicolous homobasidiomycetes and their relatives, from which we obtained mainly nuclear and some mitochondrial rDNA sequences. Phylogenetic analyses in this study indicate that a lichenicolous habit arose in four major clades. In two of these clades the habit represents a major evolutionary theme linked to the origin of well-known basidiolichens. The phylogenetic diversity of these fungi indicates that the lichenicolous habit arose recently and independently in the mushroom-forming fungi.