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.

Before the application of molecular techniques, evolutionary relationships between sequestrate genera and their epigeous counterparts in the Russulaceae were unclear. Based on overwhelming evidence now available, personal observations, and consideration of the International Code for Nomenclature of Algae, Fungi and Plants, we combine the overlapping sequestrate generic names Bucholtzia, Cystangium, Elasmomyces, Gymnomyces, Macowanites, and Martellia with the agaricoid genus Russula. This nomenclatural action follows precedents set by earlier mycologists and continues an effort to create clarity in our understanding of the evolutionary affiliations among sequestrate fungi - particularly the Russulaceae. We also provide the first comprehensive list of described sequestrate species of Russula.

Russula is a worldwid genus which has a high species diversity . Aiming accurate and rapid species identification, candidate genes nLSU (28S), ITS, tef-1alpha, mtSSU, rpb1, and rpb2, were analysed as potential DNA barcodes. This analysis included 433 sequences from 38 well-circumscribed Russula species of eight subgenera. Two vital standards were analysed for success species identification using DNA barcodes, specifically inter- and intra-specific variations together with the success rates of PCR amplification and sequencing. Although the gap between inter- and intra-specific variations was narrow, ITS met the qualification standards for a target DNA barcode. Overlapping inter- and intra-specific pairwise distances were observed in nLSU, tef-1alpha, mtSSU, and rpb2. The success rates of PCR amplification and sequencing in mtSSU and rpb1 were lower than those of others. Gene combinations were also investigated for resolution of species recognition. ITS-rpb2 was suggested as the likely target DNA barcode for Russula, owing to the two viatal standards above. Since nLSU has the lowest minimum of inter-specific variation, and tef-1alpha has the highest overlap between intra- and inter-species variations among the candidate genes, they are disqualified from the selection for DNA barcode of Russula.

Ectomycorrhizal (ECM) fungi, symbiotic mutualists of many dominant tree and shrub species, exhibit a biogeographic pattern counter to the established latitudinal diversity gradient of most macroflora and fauna. However, an evolutionary basis for this pattern has not been explicitly tested in a diverse lineage. In this study, we reconstructed a mega-phylogeny of a cosmopolitan and hyperdiverse genus of ECM fungi, Russula, sampling from annotated collections and utilizing publically available sequences deposited in GenBank. Metadata from molecular operational taxonomic unit cluster sets were examined to infer the distribution and plant association of the genus. This allowed us to test for differences in patterns of diversification between tropical and extratropical taxa, as well as how their associations with different plant lineages may be a driver of diversification. Results show that Russula is most species-rich at temperate latitudes and ancestral state reconstruction shows that the genus initially diversified in temperate areas. Migration into and out of the tropics characterizes the early evolution of the genus, and these transitions have been frequent since this time. We propose the 'generalized diversification rate' hypothesis to explain the reversed latitudinal diversity gradient pattern in Russula as we detect a higher net diversification rate in extratropical lineages. Patterns of diversification with plant associates support host switching and host expansion as driving diversification, with a higher diversification rate in lineages associated with Pinaceae and frequent transitions to association with angiosperms.

A phylogenetic analysis of Lactarius sect. Deliciosi was performed based on collections of all known species. Several samples of each species were included, originating from a wide geographic range. The two DNA regions we used (ITS and a part of the gene encoding glyceraldehyde-3-phosphate dehydrogenase) showed an incongruent phylogenetic signal. Much attention was paid to carefully observed macro- and micromorphological characters to draw taxonomic conclusions. We currently accept 38 taxa (31 species and seven varieties) in Lactarius sect. Deliciosi worldwide; four species are new to science. More sampling is needed to resolve the status of the North American varieties. Our knowledge of the Asian species in this section remains fragmentary. The monophyly of the section and its position within Lactarius subgenus Piperites, as proposed in recent morphology-based classification schemes, is confirmed. The intrasectional relationships however do not coincide with the color of the latex (as previously supposed). Intercontinental conspecificity is low in general. The name L. deliciosus is wrongfully applied in North and Central America and only two species seem to occur in both Asia and Europe.

Although Lactarius sect. Deliciosi (Fr.) Redeuilh, Verbeken & Walleyn (syn. Lactarius sect. Dapetes) is a readily identifiable group in the field, it is exceedingly difficult to correctly identify species with orange to reddish orange latex. A lack of careful study of these species in North America in general, and the Pacific Northwest more specifically, makes species identification often impossible. One common undescribed Pacific Northwest species, which begins fruiting rather early in the season, is described here as Lactarius aestivus sp. nov. It is found in conifer forests dominated by Abies Mill. and Tsuga Carriere, and is characterized by bright orange latex and zonate, bright to pale orange pileus that only rarely stains greenish. A phylogenetic analysis based on ITS sequences supports the species delimitation.

Distinguishing individual Russula species can be very difficult due to extensive phenotypic plasticity and obscure morphological and anatomical discontinuities. In this study, we use the internal transcribed spacer (ITS) and 28S nuclear ribosomal large subunit (LSU) markers to identify and study the genetic diversity of species in the Russula subgenus Compacta in Korea. We focus on two morphologically similar species that are often misidentified for each other: R. nigricans and R. subnigricans. Based on molecular phylogenetic analyses, we identify three subgroups of R. nigricans, with two from Asia and one from Europe/North America. Surprisingly, we find Korean R subnigricans are more closely related to R. eccentrica from North America than the type specimen of R. subnigricans from Japan. These molecular data, along with habitat data, reveal that Korean R. subnigricans had previously been misdassified and should now be recognized as R. eccentrica. Both ITS and LSU exhibit high interspecific and low intraspecific variation for R. eccentrica, R. nigricans, and R. subnigricans. These markers provide enough resolutional power to differentiate these species and uncover phylogeographic structure, and will be powerful tools for future ecological studies of Russula.

This paper investigates species delimitation within the Lactarius gerardii species complex and explores its taxonomic and geographical extent. A combined molecular phylogeny based on ITS, LSU and rpb2 gene sequences is constructed and morphological characters are evaluated. While L. gerardii was originally described from North America, it has later been reported from all over Asia. Therefore a worldwide sampling range was aimed at, including species exhibiting morphological affinities with L. gerardii. The phylogenetic analyses indicate that intercontinental conspecificity in L. gerardii is absent. Thirty strongly supported clades are retrieved of which 18 are morphologically identifiable species. The group is elevated to Lactarius subg. Gerardii stat. nov. It includes, apart from L. gerardii s.l., L. atrovelutinus, L. bicolor, L. ochrogalactus, L. petersenii, L. reticulatovenosus, L. sepiaceus, L. subgerardii and L. wirrabara, as well as the pleurotoid L. uyedae. The paraphyletic nature of the genus Lactarius is confirmed. Lactarius subg. Gerardii appears not affiliated with L. subg. Plinthogalus and this can be substantiated morphologically. No representatives are known from Europe, Africa or South America. The high frequency of intercontinental sister relationships observed between America, Asia and the Australian region, suggests multiple migration and speciation events have occurred across continents.

In this second of a series of three papers, new combinations in the genus Lactifluus are proposed. This paper treats Lactarius subg. Gerardii (proposed here as new combination in Lactifluus). In this subgenus 17 combinations at species level are proposed.

Although Sikkim belongs to one of the Global Biodiversity Hotspots, little is known about its ectomycorrhizal fungi, and even less about the main genera of Russulales, i.e. Lactarius, Lactifluus, Multifurca and Russula. Combining a multilocus genealogical and morphological study, we aimed to document the diversity within Lactifluus volemus sensu lato of Sikkim Himalaya. We compared nuclear ITS and LSU rDNA, nuclear rpb1 and rpb2 protein-coding, and mitochondrial atp6 protein-coding genealogies to determine species boundaries. Interspecific relationships were inferred from the combined dataset. Bayesian and maximum likelihood single-locus genealogies are concordant and support recognition of six species. Three of these could be identified by unique morphological characteristics and are described as new species: L. dissitus, L. leptomerus and L. versiformis.

Lactarius volemus (Fr.: Fr.) Fr. is a well known and morphologically easily recognizable milkcap of the Northern hemisphere, forming ectomycorrhiza with both deciduous and coniferous trees. It was originally described from Europe, but is also reported in other continents. Although it is characterized by several unique macro- and micromorphological features, substantial variation in colour, lamellae spacing and changing and staining of the latex has been recorded and it is therefore considered as a putatively unresolved species complex. This study explores the concordance between morphological and phylogenetic species concepts within L. volemus sensu lato of northern Thailand, combining a critical morphological scrutiny with a multiple gene genealogy based on LSU, ITS and rpb2 nuclear sequences. Twelve strongly supported monophyletic clades and six terminal branches are discernable in all phylogenetic trees and represent 18 phylogenetic species. Six of the monophyletic clades can be morphologically distinguished and are described as new species: L. acicularis, L. crocatus, L. distantifolius, L. longipilus, L. pinguis and L. vitellinus. Five other clades also show some morphological differences, but these are too subtle and do not allow for a clear-cut species delimitation without the corroboration of molecular data. Lactarius volemus sensu lato of northern Thailand is therefore still considered as a partially cryptic species complex. Pleurolamprocystidia, pileipellis hairs and to a lesser degree also pileus colour are important diagnostic characteristics. Spore morphology, latex discoloration and pileus surface texture are less useful as diagnostic features. Whether this rich diversity is the result of in situ Pleistocene survival or post-glacial expansion and subsequent radiation, has yet to be revealed.

This study provides morphological and molecular evidence (from nuclear ITS, LSU, and rpb2 DNA sequences) for three previously unrecognized species within the morphospecies Lactifluus volemus from Europe. Phylogenetic species are supported by both a multi-locus tree-based method and Bayesian species delimitation. Lactifluus volemus and Lactifluus oedematopus are provided with a new description, and a third species, Lactifluus subvolemus, is described as new to science. Lactifluus oedematopus can be easily recognized by its short pileipellis hairs. Both L. volemus and L. subvolemus have longer pileipellis hairs and can only be distinguished from each other based on cap colour. Intermediary colour forms, however, occur as well, and cannot be identified as either L. volemus or L. subvolemus without molecular data. Revealing that L. volemus--already considered extinct in the Netherlands and the Belgian Flemish region, and declining in other European countries--is actually a complex of three species that are even more vulnerable to extinction, this study emphasizes the fundamental role of taxonomy in species conservation.

Thirteen species and one variety of the genus Lactarius (Russulaceae, Russulales) have been published from China. Since the original descriptions and illustrations are often poor, it is difficult to understand the concepts of these taxa. Therefore, the type specimens of all these taxa were traced, reviewed and (or) re-examined by employing modern taxonomic methods. The type collections of L. atrosquamulosus and L. omeiensis could not be found. The type collection of L. minimus var. macrosporus was found to consist of mixed material belonging to two different species and a lectotype, which belongs to Lactarius subgen. Russularia, sect. Olentes was designated. Lactarius squamulosus turned out to be a synonym of L. gracilis and L. wangii was synonymized here with L. volemus. Except for L. wangii, the others were known only from China or Asia. In total, ten taxa were provided with modern or new macromorphological descriptions based on the dried basidiocarps and with illustrations of basidiospores, pleuromacrocystidia, pileipellis and (or) stipitipellis. As a result of this re-examination, the differences between these taxa and their closely related taxa were discussed and their taxonomic positions in four contemporary infrageneric classification systems of Lactarius were proposed. Based on recent conspecific collections, information on habitats and geographical distribution of some species was provided.

As a recent group mainly defined by molecular data the genus Lactifluus is in need of further study to provide insight into the morphological and molecular variation within the genus, species limits and relationships. Phylogenetic analyses of nuc rDNA ITS1-5.8S-ITS2 (ITS), D1 and D2 domains of nuc 28S rDNA (28S), and part of the second largest subunit of the RNA polymerase II (rpb2) (6-7 region) sequences of 28 samples from southern China revealed three new lineages of Lactifluus. Two of them are nested in a major clade that includes the type of Lactifluus and here is treated as two new sections: L. sect. Ambicystidiati and L. sect. Tenuicystidiati. Lactifluus ambicystidiatus, described here as a new species (= sect. Ambicystidiati), has both lamprocystidia and macrocystidia in the hymenium, a unique combination of features within Russulaceae. Furthermore, only remnants of lactiferous hyphae are present in L. ambicystidiatus and our results suggest that the ability to form a lactiferous system has been lost in this lineage. Lactifluus sect. Tenuicystidiati forms a strongly supported monophyletic group as a sister lineage to L. sect. Lactifluus. We recognize it based on the thin-walled macrocystidia and smaller ellipsoid spores with an incomplete reticulum compared with L. sect. Lactifluus. The former placement of L. tenuicystidiatus in the African L. sect. Pseudogymnocarpi is not supported. Using genealogical concordance we recognize five phylogenetic species within L. sect. Tenuicystidiati and describe two of these as new, L. subpruinosus and L. tropicosinicus. The third lineage, represented by L. leoninus, forms a sister group to L. subg. Lactariopsis sensu stricto. The three lineages provide further evidence for morphological features in Lactifluus being homoplasious. Some sections and species complexes are likely to be composed of more species and merit further investigations. Subtropical-tropical Asia is likely a key region for additional sampling.

Yunnan is an area rich in wild commercial fungi resources, namely, fungi sold in markets. Much attention has been paid to fungal resources in the past. However, comprehensive investigation and studies on the resources were wanting. Through investigation, collection and identification of species, the geographical distribution patterns, seasonal changes and ranking based on the trade volume and the economic value of the resources were documented continuously from 1997 to 2001. In total, 207 species (including varieties and forms) belonging to 64 genera are recognized, showing high diversity and high endemicity. Among the species, those of the genera Boletus, Tricholoma, Termitomyces, Thelephora, Russula, Lactarius, and Ramaria are main commercial fungi. Despite artificial selection, commercial fungi show obvious geographical distribution patterns: southern Yunnan is rich in tropical species and northwestern Yunnan is rich in temperate alpine and subalpine species. Central and southwestern Yunnan fungal communities display subtropical and temperate characters. Each area possesses its own typical species and they are related by some transitional ones. We ranked the commercial fungi species in the order of trade volume. Those of grade I and II are the dominant species. Almost 90% of the commercial fungi are edible and about 5% are medicinal, while 7% are poisonous. The economic value of each species is also provided.

野生贸易真菌即市场上出售的野生真菌，云南的野生贸易真菌资源十分丰富且长期以来受到关注。但以往对于这一资源的全面调查和研究较为缺乏。本项目通过市场调查、标本采集和鉴定，自1997～2001年连续4年对云南野生贸易真菌从种类、地理分布、季节变化、基于贸易量的优势度评价和经济价值5方面进行研究。云南野生贸易真菌已知共64属207种（含变种、变型），以担子菌中的牛肝菌属（Boletus）、口蘑属（Tricholoma）、鸡土从菌属（Termitomyces）、革菌属（Thelephora）、红菇属（Russula）、乳菇属（Lactarius）、丛枝瑚属（Ramaria）为主，表现出较高的多样性和较强的地区特有性。尽管具有人为选择的因素，但云南野生贸易真菌仍表现出较强的地理分布特异性：滇南地区包含较多的热带种类，具有较强的热带性质，而滇西北则具有较强的温带高山、亚高山性质，滇中、滇西南等地表现出亚热带和温带的过渡特征。以上各地区既有各自的代表种类，又通过某些过渡类群存在一定的联系。根据各个种贸易量的相对大小即优势度将贸易真菌分为4个等级，其中的优势Ⅰ级和优势Ⅱ级为主导种类。云南贸易真菌中约近90%的种类为食用菌，5%为药用菌，另有约7%为有毒种类。对每一种贸易真菌的经济价值给予了评价。