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A new attempt to classify the families of the Helotiales



The Helotiales are one of the larger orders of Ascomycota, including about 330 genera and roughly 2,500 species (other estimates give >3,000 spp.). This circumscription excludes the Leotiales (a paraphyletic group comprising Geoglossaceae and Leotiaceae), Phacidiales (in an extended concept including Phacidiaceae, Tympanidaceae and Helicogoniaceae), Rhytismatales, and Erysiphales. Nannfeldt (1932) distinguished only three families to correspond to this restricted circumscription (Dermateaceae, Hyaloscyphaceae, Helotiaceae). Korf (1973) recognized three additional families (Ascocorticiaceae, Hemiphacidiaceae and Sclerotiniaceae). Since then some further families have been proposed (Gelatinodiscaceae S.E Carp. 1976; Loramycetaceae Dennis ex Digby & Goos 1988; Vibrisseaceae Korf 1990; Rutstroemiaceae Holst-Jensen, L.M. Kohn & T. Schumach. 1997; Roesleriaceae Y.J. Yao & Spooner 1999; Lachnaceae Raitviir 2004). Here we recognize 25 families within the order. In addition to those mentioned above, these are: Ascodichaenaceae, Arachnopezizaceae, Calloriaceae, Cenangiaceae (=Hemiphacidiaceae), Chaetomellaceae, Chlorociboriaceae, Cordieritidaceae, Drepanopezizaceae, Godroniaceae, Heterosphaeriaceae, Mitrulaceae, Mollisiaceae, Pezizellaceae, Ploettnerulaceae. Some of them have been proposed already in the 19th century but had not yet received approval. The circumscription of some families is substantially changed based on presently available data. Several families or subfamilies turned out to be wastebaskets, particularly the Dermateaceae, Encoelioideae, and Helotiaceae. We also propose five undescribed lineages: Bryoglossum, Discinella-Pezoloma, Hysteropezizella, Stamnaria, Strossmayeria. These results are based on the study of morphological characters of sexual and asexual state, combined with molecular data; thereby paraphyletic groups were accepted if supported by morphology. Molecular data are still lacking for many genera, and further families need to be recognized in the future. Some striking correlations between molecular and morphological data became apparent. One of them concerns the ionomidotic reaction (IR), another an attribute of living cells, the refractive vacuolar bodies (VBs). To date neither of these two characters had been found associated in a single species. IR occurs with significant frequency in the Cordieritidaceae, and VBs in the Hemiphacidiaceae, here tentatively included in Cenangiaceae. Baral (1987) and Verkley (1992–95) have shown that ascus apical structures serve as valuable markers at the genus or family level, and current molecular studies confirm the taxonomic value of these amyloid ring types.
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... Author citations are given according to Index Fungorum (2016). Taxonomy and nomenclature (families and genera) are given according to Baral et al. (2015) and Jaklitsch et al. (2016). Taxa within families are listed in alphabetical order. ...
... Fr., differs from other members of the genus in having both cylindrical and lanceolate paraphysis apices instead of cylindrical or clavate at apical portion, ascus apical ring of Calycina-type instead of Conchatium-type, Hymenoscyphus-type or J-, and absence of refractive vacuolar bodies in paraphyses and excipular cells (Baral & Krieglsteiner 1985, Triebel & Baral 1996, Döbbeler 1999, Chlebicka & Chlebicki 2007, Baral et al. 2013. The phylogeny of the order Helotiales were preliminarily reconstructed based on ITS and large subunit of the nuclear ribosomal DNa sequences (Baral et al. 2015), however the relationships of the morphology-based families were not well elucidated by the phylogram, within which C. gramineum, as a separate lineage, was distant from the clade containing C. coronatum, the type species of Cyathicula. DNa sequences of C. gramineum are not available in either GenBank or Chinese material. ...
Two new species of Crocicreas are established based on morphological features and DNA sequence data. Crocicreas luteolum is distinct by combination of the following features: Caulicolous, hymenium surface yellow, margin plane, ectal excipulum of textura prismatica, asci J+, 62-81 × 6.0-7.7 μm, and ascospores fusoid, biguttulate, 11-14 × 2.2-3.3 μm. Crocicreas pseudobambusae is featured by combination of bambusicolous, hymenium surface white to beige, margin plane, ectal excipulum of textura intricata, asci J+, 36-58 × 3.5-5.5 μm, and ascospores ellipsoid, eguttulate, 4.5-7.7 × 1.8-2.5 μm. Description, illustration and comparison with related fungi are provided for each species. Sequence analyses of the internal transcribed spacer of nuclear ribosomal DNA are used to confirm their generic positions.
The class Leotiomycetes encompasses many fungi that were historically classified as inoperculate discomycetes. Molecular phylogenetics has changed our perception of the diversity of higher taxonomic lineages and morphologies in the class as well as our understanding of how these clades are related to one another. Leotiomycetes are found in all environments where researchers have explored and have myriad ecological strategies – including economically important pathogens (e.g., powdery mildews on various plants and the causal agent of the white-nose syndrome of bats), endophytes, saprobes, and mycorrhizae. In this article, we provide a summary of the morphological and ecological diversity of Leotiomycetes, and an overview of the taxonomic diversity and systematics. Major challenges in studying this group include historical biases in sampling outside of temperate Europe and North America and a lack of sequence data for many taxa especially in the sprawling mega-order Helotiales. With the help of environmental sequencing and genomic-scale data, researchers are beginning to reveal new perspectives on Leotiomycetes ecology, evolution, and systematics.
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Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. These fungi are commonly detected in cultures from diseased tissue and from environmental DNA extracts. The identification of specimens from such character-poor samples increasingly relies on DNA sequencing. However, the current classification of Leotiomycetes is still largely based on morphologically defined taxa, especially at higher taxonomic levels. Consequently, the formal Leotiomycetes classification is frequently poorly congruent with the relationships suggested by DNA sequencing studies. Previous class-wide phylogenies of Leotiomycetes have been based on ribosomal DNA markers, with most of the published multi-gene studies being focussed on particular genera or families. In this paper we collate data available from specimens representing both sexual and asexual morphs from across the genetic breadth of the class, with a focus on generic type species, to present a phylogeny based on up to 15 concatenated genes across 279 specimens. Included in the dataset are genes that were extracted from 72 of the genomes available for the class, including 10 new genomes released with this study. To test the statistical support for the deepest branches in the phylogeny, an additional phylogeny based on 3156 genes from 51 selected genomes is also presented. To fill some of the taxonomic gaps in the 15-gene phylogeny, we further present an ITS gene tree, particularly targeting ex-type specimens of generic type species. A small number of novel taxa are proposed: Marthamycetales ord. nov., and Drepanopezizaceae and Mniaeciaceae fams. nov. The formal taxonomic changes are limited in part because of the ad hoc nature of taxon and specimen selection, based purely on the availability of data. The phylogeny constitutes a framework for enabling future taxonomically targeted studies using deliberate specimen selection. Such studies will ideally include designation of epitypes for the type species of those genera for which DNA is not able to be extracted from the original type specimen, and consideration of morphological characters whenever genetically defined clades are recognized as formal taxa within a classification.
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Discomycetes are an artificial grouping of apothecia-producing fungi in the phylum Ascomycota. Molecular-based studies have revealed that the discomycetes can be found among ten classes of Ascomycota. The classification of discomycetes has been a major challenge due to the lack of a clear understanding of the important morphological characters, as well as a lack of reference strains. In this review, we provide a historical perspective of discomycetes, notes on their morphology (including both asexual and sexual morphs), ecology and importance, an outline of discomycete families and a synoptical cladogram of currently accepted families in Ascomycota showing their systematic position. We also calculated evolutionary divergence times for major discomycetous taxa based on phylogenetic relationships using a combined LSU, SSU and RPB2 data set from 175 strains and fossil data. Our results confirm that discomycetes are found in two major subphyla of the Ascomycota: Taphrinomycotina and Pezizomycotina. The taxonomic placement of major discomycete taxa is briefly discussed. The most basal group of discomycetes is the class Neolectomycetes, which diverged from other Taphrinomycotina around 417 MYA (216–572), and the most derived group of discomycetes, the class Lecanoromycetes, diverged from Eurotiomycetes around 340 MYA (282–414). Further clarifications based on type specimens, designation of epitypes or reference specimens from fresh collections, and multi-gene analyses are needed to determine the taxonomic arrangement of many discomycetes.
Cenangiaceae Rehm (= Hemiphacidiaceae Korf)-15 genera (c
  • Fam
Fam. Cenangiaceae Rehm (= Hemiphacidiaceae Korf)-15 genera (c.
Spooner-2 genera (c. 7): Roesleria, Roeslerina ? Discinella-Pezoloma lineage-2-3 gen. (c. 15): Discinella (= Geocoryne)
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  • Y J Roesleriaceae
  • Yao
Fam. Roesleriaceae Y.J. Yao & Spooner-2 genera (c. 7): Roesleria, Roeslerina ? Discinella-Pezoloma lineage-2-3 gen. (c. 15): Discinella (= Geocoryne), Pezoloma (= Articulospora)