Kerry Knudsen

Families of Dothideomycetes

Dothideomycetes comprise a highly diverse range of fungi characterized mainly by asci with two wall layers (bitunicate asci) and often with fissitunicate dehiscence. Many species are saprobes, with many asexual states comprising important plant pathogens. They are also endophytes, epiphytes, fungicolous, lichenized, or lichenicolous fungi. They occur in terrestrial, freshwater and marine habitats in almost every part of the world. We accept 105 families in Dothideomycetes with the new families Anteagloniaceae, Bambusicolaceae, Biatriosporaceae, Lichenoconiaceae, Muyocopronaceae, Paranectriellaceae, Roussoellaceae, Salsugineaceae, Seynesiopeltidaceae and Thyridariaceae introduced in this paper. Each family is provided with a description and notes, including asexual and asexual states, and if more than one genus is included, the type genus is also characterized. Each family is provided with at least one figure-plate, usually illustrating the type genus, a list of accepted genera, including asexual genera, and a key to these genera. A phylogenetic tree based on four gene combined analysis add support for 64 of the families and 22 orders, including the novel orders, Dyfrolomycetales, Lichenoconiales, Lichenotheliales, Monoblastiales, Natipusillales, Phaeotrichales and Strigulales. The paper is expected to provide a working document on Dothideomycetes which can be modified as new data comes to light. It is hoped that by illustrating types we provide stimulation and interest so that more work is carried out in this remarkable group of fungi.

The Lichen Connections of Black Fungi

Many black meristematic fungi persist on rock surfaces—hostile and exposed habitats where high doses of radiation and periods of desiccation alternate with rain and temperature extremes. To cope with these extremes, rock-inhabiting black fungi show phenotypic plasticity and produce melanin as cell wall pigments. The rather slow growth rate seems to be an additional prerequisite to oligotrophic conditions. At least some of these fungi can undergo facultative, lichen-like associations with photoautotrophs. Certain genera presenting different lifestyles are phylogenetic related among the superclass Dothideomyceta. In this paper, we focus on the genus Lichenothelia, which includes border-line lichens, that is, associations of melanised fungi with algae without forming proper lichen thalli. We provide a first phylogenetic hypothesis to show that Lichenothelia belongs to the superclass Dothideomyceta. Further, culture experiments revealed the presence of co-occurring fungi in Lichenothelia thalli. These fungi are related to plant pathogenic fungi (Mycosphaerellaceae) and to other rock-inhabiting lineages (Teratosphaeriaceae). The Lichenothelia thallus-forming fungi represent therefore consortia of different black fungal strains. Our results suggest a common link between rock-inhabiting meristematic and lichen-forming lifestyles of ascomycetous fungi.

Phylogeny of the Acarosporaceae (Lecanoromycetes, Ascomycota, Fungi) and the evolution of carbonized ascomata

The phylogeny of the Acarosporaceae (Lecanoromycetes, Acarosporomycetidae, Acarosporales) is investigated using data from three molecular markers; nuclear ITS-LSU rDNA, mitochondrial SSU and β-tubulin. Acarosporaceae is shown to be constituted by six main clades; Myriospora, Timdalia, Pleopsidium, a clade composed by “Acarospora” rhizobola and “A.” terricola, the poorly supported Sarcogyne clade (including several Polysporina and Acarospora species) and the Acarospora clade (including the type of Polysporina, P. simplex, and several other Polysporina species). The common ancestor of the Acarosporaceae did not produce strongly black pigmented (carbonized or melanized) ascomata, but this trait has arisen secondarily and independently numerous times in the evolution of the group. The number of changes in character states of both carbonized epihymenium and carbonized exciple are considerably more than the minimum number. The genera Sarcogyne and Polysporina—largely circumscribed based on the presence of black pigmented ascomata—are shown to be distinctly non-monophyletic. The presence of green algae in the ascoma margin (lecanorine or lecideine ascomata) may vary even within single species.

Three new species of Rinodina (Physciaceae) and a new record from North America

Abstract Rinodina campestris, R. megistospora and R. terricola are described as new to science. Rinodina boleana is recorded for the first time from North America and is compared in detail to R. pyrina and R. imshaugii and all are shown to possess Dirinaria–type spores.

A contribution to the study of Acarosporaceae in South America

Acarospora dissecta (Bolivia) and Sarcogyne brunnea (Bolivia, Ecuador) are described as new to science. Acarospora trachyticola, a common effigurate species in Peru, is revised and reported as new for Argentina, Bolivia and Venezuela. Acarospora brasiliensis is considered as a later synonym of A. lorentzii, which is reported new for Peru. Sarcogyne terrena is revised. Silobia smaragdula is verified as occurring in Chile. Polysporina urceolata is reported new to South America from Bolivia.

A new Lichenostigma species (Genus incertae sedis) from southern California

Abstract Lichenostigma saxicola, growing on silicate rocks and lichens, is described from southern California from both the Sonoran and Mojave deserts as well as from the Santa Monica Mountains on the coast. The species belongs to the subgenus Lichenostigma, has a non-amyloid centrum, and dark one-septate ascospores, 10–12 × 5–6 µm, cells equal or not, constricted at the septum, the walls of over-mature ascospores becoming granular-verrucose. The species is considered facultatively lichenicolous, not host specific, and is pathogenic.

A new Lepraria (Stereocaulaceae) from the Santa Monica Mountains in southern California

Abstract Lepraria santamonicae K. Knudsen & Elix is described as a new species of lichenized fungi growing on soil and rock in southern California. It is characterized by the presence of the chlorinated β-orcinol depsidones, argopsin and norargopsin.

A new species of Placocarpus (Verrucariaceae) from southern California

A new species, Placocarpus americanus, is described from the Santa Monica Mountains in Southern California. It is a juvenile parasite on Protoparmeliopsis muralis and differs from Placocarpus schaereri in having smaller non-halonate ascospores, a negative iodine reaction of the medulla, lack of inspersion of the medulla with small crystals, and having a thallus of dispersed areoles.

Lichens of the Granite Mountains, Sweeney Granite Mountain Desert Research Center, Southwestern Mojave Desert, San Bernardino County, California

Abstract. 75 species representing 40 genera of lichens, lichenicolous and a lignicolous fungus are reported from the Granite Mountains in the southwestern Mojave Desert. Acarospora arenaria H. Magn. is reported new for California.

Acarospora ramosa (Acarosporaceae), a new effigurate yellow species from South America

Acarospora ramosa K. Knudsen & Flakus is described as new to science from the Bolivian Andes. It is characterized by a yellow, epruinose, rugulose thallus with a distinct effigurate margin, punctiform apothecia, and thin, branching and anastomosing paraphyses. The main diagnostic substances the new species produces are rhizocarpic and gyrophoric acids.