Stop black and white thinking: Russula subgenus Compactae (Russulaceae, Russulales) in Europe revised.

Russula subgenus Compactae is a group of ectomycorrhizal basidiomycetes, usually with large pileate fruitbodies. European members of the group are characterised by the absence of bright colours on the surfaces of their pilei, the context turning grey to black after cutting, the abundance of short lamellulae in the hymenophore, and spores with an inamyloid suprahilar spot and with low reticulate ornamentation. Our multi-locus phylogenetic study confirmed that this morphological delimitation corresponds to a well-supported clade. Within this clade, 16 species are recognised in Europe, of which five belong to the R. albonigra lineage and were described in a previous study, while eleven are fully described in this study. The application of the names R. acrifolia, R. adusta, R. anthracina, R. atramentosa, R. densissima, R. nigricans and R. roseonigra is based on the position of sequences retrieved from types or authentic material. Based on type sequences, R. fuliginosa is synonymised with R. anthracina and two varieties of R. anthracina are considered synonyms of R. atramentosa. The application of the name R. densifolia is based on a morphological match with the traditional species interpretation and the neotype specimen. Three species are described as new, R. marxmuelleriana sp. nov., R. picrophylla sp. nov. and R. thuringiaca sp. nov. This study recognises three major lineages and two species with isolated positions within the European Compactae and a morphological barcode was assigned to the species using an analysis of 23 selected characters. A search of publicly available sequences from the UNITE database revealed that the majority of species are host tree generalists and widely distributed in temperate and Mediterranean areas of Europe. Russula adusta is the only species so far proven to form ectomycorrhiza exclusively with conifers. Citation: De Lange R, Kleine J, Hampe F, et al. 2023. Stop black and white thinking: Russula subgenus Compactae (Russulaceae, Russulales) in Europe revised. Persoonia 51: 152-193. doi: 10.3767/persoonia.2023.51.04.

Diversity of colacosome-interacting mycoparasites expands the understanding of the evolution and ecology of Microbotryomycetes.

Mycoparasites in Basidiomycota comprise a diverse group of fungi, both morphologically and phylogenetically. They interact with their hosts through either fusion-interaction or colacosome-interaction. Colacosomes are subcellular structures formed by the mycoparasite at the host-parasite interface, which penetrate the parasite and host cell walls. Previously, these structures were detected in 19 fungal species, usually by means of transmission electron microscopy. Most colacosome-forming species have been assigned to Microbotryomycetes (Pucciniomycotina, Basidiomycota), a highly diverse class, comprising saprobic yeasts, mycoparasites, and phytoparasites. In general, these myco- and phytoparasites are dimorphic organisms, with a parasitic filamentous morph and saprobic yeast morph. We investigated colacosome-forming mycoparasites based on fungarium material, freshly collected specimens, and cultures of yeast morphs. We characterised the micromorphology of filamentous morphs, the physiological characteristics of yeast morphs, and inferred phylogenetic relationships based on DNA sequence data from seven loci. We outline and employ an epifluorescence-based microscopic method to assess the presence and organisation of colacosomes. We describe five new species in the genus Colacogloea, the novel dimorphic mycoparasite Mycogloiocolax gerardii, and provide the first report of a sexual, mycoparasitic morph in Colacogloea philyla and in the genus Slooffia. We detected colacosomes in eight fungal species, which brings the total number of known colacosome-forming fungi to 27. Finally, we revealed three distinct types of colacosome organisation in Microbotryomycetes. Taxonomic novelties and typifications: New family: Mycogloiocolacaeae Schoutteten & Yurkov; New genus: Mycogloiocolax Schoutteten & Rödel; New species: Colacogloea bettinae Schoutteten & Begerow, C. biconidiata Schoutteten, C. fennica Schoutteten & Miettinen, C. microspora Schoutteten, C. universitatis-gandavensis Schoutteten & Verbeken, Mycogloiocolax gerardii Schoutteten & Rödel; New combinations: Slooffia micra (Bourdot & Galzin) Schoutteten, Fellozyma cerberi (A.M. Yurkov et al.) Schoutteten & Yurkov, Fellozyma telluris (A.M. Yurkov et al.) Schoutteten & Yurkov; Epitypifications (basionyms): Achroomyces insignis Hauerslev, Platygloea micra Bourdot & Galzin, Platygloea peniophorae Bourdot & Galzin; Lectotypification (basionym): Platygloea peniophorae Bourdot & Galzin Citation: Schoutteten N, Yurkov A, Leroux O, Haelewaters D, Van Der Straeten D, Miettinen O, Boekhout T, Begerow D, Verbeken A (2023). Diversity of colacosome-interacting mycoparasites expands the understanding of the evolution and ecology of Microbotryomycetes. Studies in Mycology 106: 41-94. doi: 10.3114/sim.2022.106.02.

Four new nodulose-spored species of Inocybe (Agaricales) from West Africa.

We describe four new nodulose-spored species of Inocybe from tropical regions of Africa: I. beninensis, I. flavipes, I. fuscobrunnea and I. pallidiangulata. The new species are recognised based on morphological data and phylogenetic analyses of ITS, 28S and RPB2 sequences. Phylogenetic analyses indicated that I. flavipes and I. beninensis are part of a subclade leading to the I. calida group. Inocybe fuscobrunnea appears sister to the I. asterospora group. Inocybe pallidiangulata is nested within a clade of mainly tropical species from South Asia, Africa, and South America, close to the subclade of I. lilacinosquamosa and I. ayangannae from Guyana. Complete descriptions and illustrations, including photographs and line drawings, and a key to nodulose-spored taxa of tropical African species of Inocybe are provided. Citation: Aïgnon HL, Jabeen S, Verbeken A, Matheny PB, Yorou NS, Ryberg M (2022). Four new nodulose-spored species of Inocybe (Agaricales) from West Africa. Fungal Systematics and Evolution 10: 1-18. doi: 10.3114/fuse.2022.10.01.

A short story of nearly everything in Lactifluus (Russulaceae).

Fungi are a large and hyper-diverse group with major taxa present in every ecosystem on earth. However, compared to other eukaryotic organisms, their diversity is largely understudied. Since the rise of molecular techniques, new lineages are being discovered at an increasing rate, but many are not accurately characterised. Access to comprehensive and reliable taxonomic information of organisms is fundamental for research in different disciplines exploring a variety of questions. A globally dominant ectomycorrhizal (ECM) fungal family in terrestrial ecosystems is the Russulaceae (Russulales, Basidiomycota) family. Amongst the mainly agaricoid Russulaceae genera, the ectomycorrhizal genus Lactifluus was historically least studied due to its largely tropical distribution in many underexplored areas and the apparent occurrence of several species complexes. Due to increased studies in the tropics, with a focus on this genus, knowledge on Lactifluus grew. We demonstrate here that Lactifluus is now one of the best-known ECM genera. This paper aims to provide a thorough overview of the current knowledge of Lactifluus, with information on diversity, distribution, ecology, phylogeny, taxonomy, morphology, and ethnomycological uses of species in this genus. This is a result of our larger study, aimed at building a comprehensive and complete dataset or taxonomic framework for Lactifluus, based on molecular, morphological, biogeographical, and taxonomical data as a tool and reference for other researchers. Citation: De Crop E, Delgat L, Nuytinck J, Halling RE, Verbeken A (2021). A short story of nearly everything in Lactifluus (Russulaceae). Fungal Systematics and Evolution 7: 133-164. doi: 10.3114/fuse.2021.07.07.

Lactifluus (Russulaceae) diversity in Central America and the Caribbean: melting pot between realms.

Species of the ectomycorrhizal genus Lactifluus, and often entire sections, are typically unique to a single continent. Given these biogeographic patterns, an interesting region to study their diversity is Central America and the Caribbean, since the region is closely connected to and often considered a part of the North American continent, but biogeographically belong to the Neotropical realm, and comprises several regions with different geologic histories. Based on a multi-gene phylogeny and morphological study, this study shows that Central America, Mexico and the Caribbean harbour at least 35 Lactifluus species, of which 33 were never reported outside of this region. It was found that species from the Caribbean generally show affinities to South American taxa, while species from the Central American mainland generally show affinities to Northern hemispheric taxa. We hypothesise that host specificity and/or climate play a crucial role in these different origins of diversity. Because of these different affinities, Caribbean islands harbour a completely different Lactifluus diversity than the Central American mainland. The majority of species occurring on the islands can be considered endemic to certain islands or island groups. In this paper, detailed morphological descriptions are given, with a focus on the unique diversity of the islands, and identification keys to all hitherto described Lactifluus species occurring in Central America and the Caribbean are provided. One new section, Lactifluus sect. Nebulosi, and three new species, Lactifluus guadeloupensis, Lactifluus lepus and Lactifluus marmoratus are described.

A multi-gene phylogeny of Lactifluus (Basidiomycota, Russulales) translated into a new infrageneric classification of the genus.

Infrageneric relations of the genetically diverse milkcap genus Lactifluus (Russulales, Basidiomycota) are poorly known. Currently used classification systems still largely reflect the traditional, mainly morphological, characters used for infrageneric delimitations of milkcaps. Increased sampling, combined with small-scale molecular studies, show that this genus is underexplored and in need of revision. For this study, we assembled an extensive dataset of the genus Lactifluus, comprising 80 % of all known species and 30 % of the type collections. To unravel the infrageneric relationships within this genus, we combined a multi-gene molecular phylogeny, based on nuclear ITS, LSU, RPB2 and RPB1, with a morphological study, focussing on five important characteristics (fruit body type, presence of a secondary velum, colour reaction of the latex/context, pileipellis type and presence of true cystidia). Lactifluus comprises four supported subgenera, each containing several supported clades. With extensive sampling, ten new clades and at least 17 new species were discovered, which highlight the high diversity in this genus. The traditional infrageneric classification is only partly maintained and nomenclatural changes are proposed. Our morphological study shows that the five featured characteristics are important at different evolutionary levels, but further characteristics need to be studied to find morphological support for each clade. This study paves the way for a more detailed investigation of biogeographical history and character evolution within Lactifluus.

Tales of the unexpected: angiocarpous representatives of the Russulaceae in tropical South East Asia.

Six new sequestrate Lactarius species are described from tropical forests in South East Asia. Extensive macro- and microscopical descriptions and illustrations of the main anatomical features are provided. Similarities with other sequestrate Russulales and their phylogenetic relationships are discussed. The placement of the species within Lactarius and its subgenera is confirmed by a molecular phylogeny based on ITS, LSU and rpb2 markers. A species key of the new taxa, including five other known angiocarpous species from South East Asia reported to exude milk, is given. The diversity of angiocarpous fungi in tropical areas is considered underestimated and driving evolutionary forces towards gasteromycetization are probably more diverse than generally assumed. The discovery of a large diversity of angiocarpous milkcaps on a rather local tropical scale was unexpected, and especially the fact that in Sri Lanka more angiocarpous than agaricoid Lactarius species are known now.

Fungi on leaf blades of Phragmites australis in a brackish tidal marsh: diversity, succession, and leaf decomposition.

Although fungi are known to colonize and decompose plant tissues in various environments, there is scanty information on fungal communities on wetland plants, their relation to microhabitat conditions, and their link to plant litter decomposition. We examined fungal diversity and succession on Phragmites australis leaves both attached to standing shoots and decaying in the litter layer of a brackish tidal marsh. Additionally, we followed changes in fungal biomass (ergosterol), leaf nitrogen dynamics, and litter mass loss on the sediment surface of the marsh. Thirty-five fungal taxa were recorded by direct observation of sporulation structures. Detrended correspondence analysis and cluster analysis revealed distinct communities of fungi sporulating in the three microhabitats examined (middle canopy, top canopy, and litter layer), and indicator species analysis identified a total of seven taxa characteristic of the identified subcommunities. High fungal biomass developed in decaying leaf blades attached to standing shoots, with a maximum ergosterol concentration of 548 +/- 83 microg g(-1) ash-free dry mass (AFDM; mean +/- SD). When dead leaves were incorporated in the litter layer on the marsh surface, fungi experienced a sharp decline in biomass (to 191 +/- 60 microg ergosterol g(-1) AFDM) and in the number of sporulation structures. Following a lag phase, species not previously detected began to sporulate. Leaves placed in litter bags on the sediment surface lost 50% of their initial AFDM within 7 months (k = -0.0035 day(-1)) and only 21% of the original AFDM was left after 11 months. Fungal biomass accounted for up to 34 +/- 7% of the total N in dead leaf blades on standing shoots, but to only 10 +/- 4% in the litter layer. These data suggest that fungi are instrumental in N retention and leaf mass loss during leaf senescence and early aerial decay. However, during decomposition on the marsh surface, the importance of living fungal mass appears to diminish, particularly in N retention, although a significant fraction of total detrital N may remain associated with dead hyphae.

The estimated impact of fungi on nutrient dynamics during decomposition of Phragmites australis leaf sheaths and stems.

Decomposition of culms (sheaths and stems) of the emergent macrophyte Phragmites australis (common reed) was followed for 16 months in the litter layer of a brackish tidal marsh along the river Scheldt (the Netherlands). Stems and leaf sheaths were separately analyzed for mass loss, litter-associated fungal biomass (ergosterol), nutrient (N and P), and cell wall polymer concentrations (cellulose and lignin). The role of fungal biomass in litter nutrient dynamics was evaluated by estimating nutrient incorporation within the living fungal mass. After 1 year of standing stem decay, substantial fungal colonization was found. This corresponded to an overall fungal biomass of 49 +/- 8.7 mg g(-1) dry mass. A vertical pattern of fungal colonization on stems in the canopy is suggested. The litter bag experiment showed that mass loss of stems was negligible during the first 6 months, whereas leaf sheaths lost almost 50% of their initial mass during that time. Exponential breakdown rates were -0.0039 +/- 0.0004 and -0.0026 +/- 0.0003 day(-1) for leaf sheaths and stems, respectively (excluding the initial lag period). In contrast to the stem tissue--which had no fungal colonization--leaf sheaths were heavily colonized by fungi (93 +/- 10 mg fungal biomass g(-1) dry mass) prior to placement in the litter layer. Once being on the sediment surface, 30% of leaf sheath's associated fungal biomass was lost, but ergosterol concentrations recovered the following months. In the stems, fungal biomass increased steadily after an initial lag period to reach a maximal biomass of about 120 mg fungal biomass g(-1) dry mass for both plant parts at the end of the experiment. Fungal colonizers are considered to contain an important fraction of nutrients within the decaying plant matter. Fungal N incorporation was estimated to be 64 +/- 13 and 102 +/- 15% of total available N pool during decomposition for leaf sheaths and stems, respectively. Fungal P incorporation was estimated to be 37 +/- 9 and 52 +/- 15% of total available P during decomposition for leaf sheaths and stems, respectively. Furthermore, within the stem tissue, fungi are suggested to be active immobilizers of nutrients from the external environment because fungi were often estimated to contain more than 100% of the original nutrient stock.