The delimitation of \u3cem\u3eFlammulina Fennae\u3c/em\u3e

Multivariate morphometric analyses of micromorphological characters measured on 35 specimens of Flammulina fennae and related species show that only a combination of spore dimensions and ixohyphidia characters are suitable for delimitation of this species. In order to confirm species identifications based on micromorphology, ribosomal ITS DNA sequences were obtained and compared with those previously deposited in GenBank, and phylogenetic analyses were performed using an ITS dataset of all known Flammulina species. All six specimens morphologically determined as F. fennae were identified by molecular data. Two of twelve specimens morphologically assigned to F. velutipes had F. elastica sequences. One ITS sequence of F. velutipes appears to be a hybrid: the ITS1 region is homologous to F. velutipes and ITS2 is homologous to another Flammulina species, F. rossica. Variability of morphocharacters observed for F. fennae and related species is discussed and compared with the data from previous studies. A key is provided to European taxa of the genus Flammulina together with a full description of F. fennae

Studies on Russula lavipes and related taxa of Russula section Xerampelinae with a predominantly olivaceous pileus

Original material of taxa of Russula sect. Xerampelinae with a mainly olivaceous pileus are compared with selected specimens. It is demonstrated that Russula clavipes, thought to be associated exclusively with conifers, may also occur with deciduous trees and grows from the temperate lowlands to arctic areas. Nomenclature and taxonomic status of other names used for similar taxa in this group are discussed. Russula xerampelina var. elaeodes and R. nuoljae are treated as the only validly published synonyms of R. clavipes

Type studies in <I>Russula</I> subgenus <I>Heterophyllidia</I> from the eastern United States

Microscopical characters of type specimens for five species in Russula subgenus Heterophyllidia: R. albiduliformis Murrill, R. flocculosa Burl., R. maculosa Murrill, R. heterosporoides Murrill and R. subgraminicolor Murrill are described in detail. Taxonomy, systematic placement and nomenclatural aspects are discussed. Both R. heterosporoides Murrill and R. subgraminicolor Murrill are likely good species of subsection Virescentinae, whereas the other three species are more difficult to place with precision, but show affinities with both Virescentinae and Heterophyllinae.</p

Type studies in &lt;I&gt;Russula&lt;/I&gt; subsection &lt;I&gt;Lactarioideae&lt;/I&gt; from North America and a tentative key to North American species

Detailed microscopical observations on four type specimens of Russula subsect. Lactarioideae from North America are presented and illustrated. As the result of our analyses, all four species are accepted as good species in Lactarioideae, although sometimes with slightly modified concept. R. brevipes is recognized by the rather short and often inflated cells in the pileipellis, large spores with spiny, subreticulate ornamentation and the distinctly amyloid suprahilar spot. Whether or not the European R. chloroides is a later synonym remains to be examined. R. inopina is characterized by filiform, flexuous-undulate terminal cells in the pileipellis, as well as on the gill edge, and it lacks shorter, mucronate pileocystidia. R. romagnesiana, originally described to replace the invalidly published, European R. chloroides var. parvispora, is here considered to be quite different from this European taxon and is accepted as distinct, native American species characterized by having equally small spores, frequently bicapitate pileocystidia near the pileus center as well as hyphal terminations with a glutinous sheath, but lacking distinct incrustations. R. vesicatoria is defined as a species of sandy Pinus stands with crowded gills, large and clavate, obtuse to capitate, often thick-walled pileocystidia, very long and slender hyphal extremities and spores with an inamyloid suprahilar spot. A tentative key to all North American Lactarioideae introduces objective microscopic features for the identification of all recognized species in this group.</p

The study of &lt;i&gt;Russula&lt;/i&gt; in the Western United States

A short history to the study of Russula in the Western United States is provided and for the first time an exhaustive list of all 49 taxa described from this part of the country has been compiled. As a start to a revision of these species, a first series of four holotypes (one from California and three from the Pacific Northwest) have here been studied microscopically, resulting in some very substantial changes concerning species concept and consequent systematic placement. Russula flava var. pacifica appears unrelated to the type variety. It is therefore excluded as member of Integroidinae, subgen. Polychromidia, and deserves probably to be upgraded to species level within subgen. Russula. The Californian R. paxilloides is lectotypified and is a good member of subgen. Russula, but is closer to sect. Persicinae than to the white-spored Vinaceae as previously suggested. Russula maxima, widely accepted as a species of subsect. Subcompactinae (subgen. Heterophyllidia), certainly does not belong there and has to be moved to subgen. Polychromidia. Finally, R. inconstans is here maintained as member of subg. Polychromidia.</p

&lt;I&gt;Russula hixsonii&lt;/I&gt; Murrill, a rare and intriguing southern species of uncertain systematic position, rediscovered in Georgia, USA

R.hixsonii Murrill, only known from its type locality in Florida, USA, is described and illustrated from a recent collection in southern Georgia and compared with the type specimen. Its very unusual combination of morphological features and eventual affinities are discussed.</p