Geoffrey Kibby

Effects of thinning treatment on an ectomycorrhizal succession under Scots pine

We describe a 16 yr dataset of ectomycorrhizal fruit bodies under Scots pine (Pinus sylvestris), starting from seedlings, and explore the effects of a 50% thinning treatment imposed in year 12. The over-riding pattern in the data was of successional development, with Paxillus involutus and Laccaria proxima in the earliest years, followed by Suillus species, while in later years Amanita and Cortinarius species became prominent. The typical pattern was for each species in turn to increase to a maximum count then gradually decline without actually disappearing from the community (an addition succession). For nine out of the 30 species recorded the time profiles were fitted significantly by a long-normal curve, although the best-fit lognormal models consistently under-estimated the peak count. Thinning increased counts of Suillus bovinus, Gomphidius roseus and Cortinarius semisanguineus, but overall its effect on the community was minor. Rainfall in September was weakly correlated with successional advancement (measured as DCA first axis scores). Mean fruiting date increased significantly as the stands aged.

Fungi of ornamental woodchips in Surrey

We report a two year survey of saprotrophic fungi colonising woodchip mulch at two contrasting sites in Surrey, a formal garden and a roadside planting scheme. Two alien species ( Stropharia aurantiaca and Psilocybe cyanescens ) occurred at both sites, along with other notable species including Psilocybe percevalii, Agrocybe putaminum and Collybia biformis . Very little fruiting occurred on areas mulched with bark chippings. In the formal garden there was virtually no repeat fruiting in successive years. At the roadside site most species fruited profusely in the first season after deposition, then decreased greatly in numbers in the second year. It is concluded that ornamental woodchips, but not bark chippings, can support diverse fungal communities including unusual species, although these assemblages are short-lived.

Leccinum revisited: A new synoptic key to species

Using the techniques of molecular analysis, mycologists’ new-found ability to compare and contrast taxa based upon their genetic structure is revolutionising our understanding of Families, Genera and Species,not just in the fungi but in all organisms.In the larger fungi it has revealed what many had already suspected - that the fruitbodies we see and collect are often amazingly ‘plastic’ in theirgrossmorphology.Differencesandvariations in appearance that formerly we would have been certain must reflect specific or generic differences, may now be revealed to represent simple extremes of external morphology.Often when their genetic structure is compared,little significant differences can be found and in the case of species such taxa must - in the opinion of many - be considered to representonespecies. Recently, H.C. den Bakker and M.E. Noordeloos among others, have been examining the genus Leccinum. Their results, published in 2005 (Bakker, 2005), presented some startling changes in our species concepts. From the 36 speciespresentedbyLannoyandEstades,plusthe three species added by Korhonen, Bakker & Noordeloos have reduced the total to just 14, a dramaticreductionbyanystandards. Presented here then is a revised synoptic key based on this work and my own field observations with notes and descriptions explaining some of the more surprising synonymies and name changes. It is important to stress, as do Bakker and Noordeloos, that our knowledge is not now complete, changes will undoubtedly continue to be made as research continues.But it is fair to say that the view of species which they present probably reflects what is ‘out there’ more accurately thananyothertodate. What has become clear is that the traditional macrocharacters of flesh colour changes and pileus colour are much more variable than we thought, and that some species have a wider host rangethanpreviouslyallowed.

Key to blackening species of Russula of Section Compactae

The blackening Russula species of the section Compactae – of which R. nigricans is the best known are quite easy to recognise as a group; their squat, robust and brittle fruitbodies start out white but rapidly discolour brown to black in all parts.The species, however, are less easily determined and a surprising amount of confusion exists in the literature and on forays as to how they are delimited. The standard British reference work by Rayner which we have used for many years is sadly now out of step with more recent treatments of this section; nomenclatural changes have occurred and new species described which necessitate changes. The following key is a distillation from the recent books by Galli (1996) and Sarnari (1995), which are founded in large part on the monograph by Romagnesi (1985). Two recently described species are included even though not yet recorded from Britain on the assumption that they may be found here. These species are marked with an asterisk. The terms SBA and SV stand for sulfobenzaldehyde and sulfovanillin, two essential chemicals if you wish to study any Russula. Add to these Melzer’s iodine solution, some ferrous sulphate and a good microscope and you have all you need to examine spores, cap cuticle and cystidia. R. densifolia in the sense of Rayner is now called R. acrifolia. Rayner describes this as fairly common although this does not tally with my personal experience; perhaps it is only locally frequent. What is now considered to be the true R. densifolia in the sense of Romagnesi has characteristic broad, inflated cap cells and is little-known in this country. What is often recorded on forays under this name is a third species R. anthracina with slender cap cells many of which are filled with large blackish-brown oily droplets when mounted in SBA or SV and with gills usually