Book of Abstracts (PDF) - International Mycological Association

IMC7 Tuesday August 13th Lectures
143 - Autecology of Hygrocybe spp. in temperate
grasslands
G.W. Griffith 1* , G.L. Easton 1 , A.W. Jones 1 , A. Stott 2 , N.
Ostle 2 & R. Bol 3
1 Institute of Biological Sciences, University of Wales
Aberystwyth, Penglais, Aberystwyth, Ceredigion SY23
3DA, Wales, U.K. - 2 Centre for Ecology and Hydrology,
Merlewood Research Station, Grange-Over-Sands,
Cumbria, LA11 6JU Cumbria, LA11 6JU, England, U.K. -
3 Institute of Grassland and Environmental Research, North
Wyke Research Station, Okehampton, Devon EX20 2SB,
England, U.K. - E-mail: gwg@aber.ac.uk
Members of the genus Hygrocybe are ubiquitous and
colourful components of many undisturbed and nutrientpoor
grasslands in Northern Europe. Through surveys of
the distribution of Hygrocybe spp. and of other
macrofungal genera showing similar patterns of
occurrence, a picture is gradually emerging of the more
important waxcap grassland sites, and of those species in
greatest need of protection. As part of a UK-based Soil
Biodiversity Programme
(http://mwnta.nmw.ac.uk/soilbio/sourhope.htm), we have
monitored the effect of various management regimes on
fruiting of Hygrocybe spp. Fine-scale mapping combined
with genetic analysis (AFLP/ISSR) is being used to
measure the extent of individual genets, with speciesspecific
PCR probes being used to establish the vertical
location of mycelia. Analysis of the natural abundance of
the stable isotopes in fruitbodies showed that grassland
Hygrocybe spp. show significant depletion for 13 C(-28 to -
30‰) and enrichment for 15 N(+12 to +18‰), a pattern that
sets them apart from most macrofungi previously
examined. Furthermore, the other macrofungi associated
with these undisturbed grasslands (eg Clavariaceae,
Geoglossaceae) have very similar isotope signatures
despite being taxonomically unrelated. Experiments using
plant litter enriched in 15 N are currently underway and will
further clarify our understanding of the role of these fungi
in nutrient cycling and explain why they are so adversely
affected by many agricultural practices.
144 - What is Agaricus cossus? - Phylogeny of the white
Hygrophorus species in Northern Europe
E. Larsson * & S. Jacobsson
Göteborg University, Dep of Biology, Box 461, SE 405 30
Göteborg, Sweden. - E-mail: ellen.larsson@systbot.gu.se
The genus Hygrophorus Fr. comprises about 40 species in
the Scandinavian countries. They are characterized by
medium to large, fleshy basidiomes that are whitish or
colored in gray, brown, yellowish orange to red. All
species grow in woodlands and are obligate mycorrhiza
formers. There are at least ten white to whitish species in
the Nordic countries. In traditional classification color or
color- changes, viscidity, odor etc. of the basidiome have
been the most important characters. However, these
characters are often vague and also dependent on
environmental conditions. For these reasons great
taxonomical and nomenclatural problems among the white
Hygrophorus species exists. The internal transcribed spacer
regions 1 and 2 and the first 900 basepairs of the 5' region
of the nuclear large subunit ribosomal DNA was sequenced
for 35 ingroup and outgroup taxa. Phylogenetic analysis
shows that Hygrophorus is a well-defined genus but the
white species do not form a monophyletic group. Host
specificity seems to be high among the analyzed taxa.
145 - Tropical Hygrophoraceae: convergent evolution
in Hygrocybe, and support for retention of Hygroaster
based on molecular evidence
S.A. Cantrell 1* , D.J. Lodge 2 , J.-M. Moncalvo 3 , R.
Vilgalys 3 , K.K. Nakasone 4 & G.W. Griffith 5
1 Science & Technology, Universidad del Turabo, PO Box
3030, Gurabo, PR 00778, U.S.A. - 2 Center for Forest
Mycology Research, USDA-FS, FPL, PO Box 1377,
Luquillo PR 00773-1377, U.S.A. - 3 Dept. Botany, Duke
Univ., Box 90339, Durham, NC 27708-0339, U.S.A. -
4 Center for Forest Mycology Research, USDA-FS, FPL,
One Gifford Pinchot Dr., Madison, WI 53705-2398, U.S.A.
- 5 Institute of Biological Sciences, Univ. of Wales
Aberystwyth Penglais, Aberystwyth, Deredigion SY23 3DA,
Wales, U.K. - E-mail: sharonac@coqui.net
The family Hygrophoraceae is highly diverse in tropical
regions where all the genera are represented
(Camarophyllopsis, Cuphophyllus, Hygroaster, Hygrocybe,
Hygrophorus and Humiditis). Hygroaster and Hygrocybe
Section Firmae are restricted to the tropics and subtropics.
Using ribosomal DNA sequences, we have obtained a
preliminary phylogeny. Despite having ornamented rather
than smooth spores, the genus Hygroaster, is a good
member of the Hygrophoraceae. With the exception of
Sections Firmae and Glutinosae, the molecular phylogeny
is concordant with the current division of Hygrocybe into
two subgenera: Hygrocybe and Pseudohygrocybe. Section
Glutinosae forms a separate clade from the other genera,
supporting recognition of the genus Gliophorus, but more
taxon sampling is needed. Within Hygrocybe ss., Section
Firmae is included in the subgenus Hygrocybe clade and is
basal to sections Hygrocybe and Chlorophanae. The most
basal members of section Firmae (H. hypohaemacta) and
Chlorophanae (H. glutinipes) that we have sampled have
similar macro- and micromorphology, except for the
presence of dimorphic basidia and spores in Section
Firmae. Section Firmae should be reclassified in subgenus
Hygrocybe. Although section Firmae may be derived from
section Coccineae in subgenus Pseudohygrocybe as
suggested by Heinemann, our results suggest that
convergent evolution is responsible for the similarity of
micromorphology in terminal species in the Sections
Firmae and Coccineae.
Book of Abstracts 47