1993 - Mycological Society of America

Poster E5; Sunday pm
Structural features and ascospore development
in the grass-epiphytic species Myriogenospora
atramentosa and Balansia linearis
Anthony E. Glem and James F. White, Jr. Dept. of Biology,
Auburn University, Montgomery, Alabama 36117
Studies were conducted on Myriogmspora atrmnentosa (Berk & Curt.)
Diehl and Bahia link Rehm) Diehl. Both fungi are epiphytic and
form black linear stromata on rolled or folded leaf surfaces. Perithecia
are entirely submerged within stromata, without emergent perithecial
necks. Filamentous ascospores become multiseptate and disarticulate
into numerous short segments (partspore initials). These reinitiate
bipolar determinate pwth to form fusifonn part-spores. In other
' linosporous ascomycetes infecting grasses and sedges, perithecia are
not fully recessed within sbomata and filamentous ascospores may
disarticulate but do not reinitiate development of segments. It is
proposed that the leaf-epiphyte B. linemis may be more appropriately
classified in the genus Myiogenospora Atk. than in Balunsiu Speg., a
genus typified by the grass endophyte B. clumceps Speg.
Poster D4; Sunday pm
Genetic recombination in the parasexual cycle
in Fusarium oxysporum f. sp. cubense
Lucrecia and David N. Kuhn. Dept. of Biological
Sciences, Florida International Univ., Miami, FL 33199.
We want to investigate the genetic recombination that may occur
during a parasexual cross of Fusmium myspoturn f. sp. cubense (Foc). We
used W irradiation to produce a variety of mutants in 12 strains of
Foc which represent three vegetative compatibility p ups from widely
separated geographic regions. UV irradiation has proved a convenient
and efficient mutagen because Foc is haploid. Multiply marked strains
will be aossed by plating them together on a selective medium that
only allows rapid growth of fwd cells (heterokaryons). Colonies from
the mimnidia from the heterokaryotic cells will be saeened for
recombination of unselected mutant phenotypes.
Colonies that show recombination of mutant phenotypes from both
parents will be further characterized by molecular techniques, such as
amplification by polymerase chain reaction (PCR) using RAPD (ran-
dom amplified polymorphic DNA) primers. Primers that give poly-
morphic amplification of DNA from the parents of the parasexual
cross can be used to analyse the progeny for inheritance of unmarked
and unselected regions of each parent's genome. In preliminary
experiments, we have detected sufficient polymorphism to idenhfy
individual isolates of Foc.
Monday, I 0 am
Intercontinental variation in three species
of Marasmius
Scott A. Gordon and Ronald H. Petersen. Dept. of Botany,
Univ. of Tennessee, Knoxville, TN 37996-1100.
Species of Hymenomycetes traditionally have been aKumscribed
using basidiome macro- and micromorphological characters, which
may be congruent or very similar aao& intercontinental ranges. Very
few taxa, howwer, have been examined to provide information on
intercontinental sexual compatibility or biochemical (enzymatic) vari-
ation. Three intercontinentally distributed species of Mmmius (M.
androstzceus, M. rotuln, and M. sanodonius) are being analyzed using
morphometrics, protein electrophoresis, and sexual compatibility.
These characters are analyzed for each species using collections and
cultures (monokaryons and dikaryons) from North America and
Europe. They exhibit a variety of intercontinental sexual compatibility
patterns, from complete intercompatibility or complete interincom-
patibility, to sweral intersterility groups within and between North
America and Euroue. These data are compared and correlated with
morphometric and' electrophoretic data, Ad substrate affinity to
provide information on intra- and intercontinental genetic variation. In
addition, speciation processes and species concepts are discussed.
Tuesday, 230 pm
Burkard spore trap monitoring
of a yard waste composting facility
Haines and Lawrence D. Syzdek. New York State
Museum, Rm. 3132 CEC, Albany, NY 12230.
The open windrow, municipal, yard waste, composting facility at Islip,
NY, was monitored by continuously operating Burkard spore trap
samplek from July 1992 to March 1993. A sampler was also operated 6
miles away to obtain background counts. Samples were scanned with a
lOOX objective and all fungal spores were divided into 30 taxonomic
categories. More than 350,000 spore records were entered into a data-
base-for analysis. The Burkard has the advantage of sampling all viable
and nonviable spores, pollens, and dust particles. A permanent slide
record is made that can be reanalyzed at any time.
The most prevalent spore emitted from the site is from Aspergillus
migatus, but it is not prevalent in background air. A.jiirnigatus was
measured in amounts from 0 to >32,000 spores/m3 of air near the site,
with an average of 865 spores/mS during the work week and 354/m3
on Sundays.
Correlation analysis of the 13 most common spore categories counted
revealed them to form four behavior groups based on timing in the air.
Ascospores, colored basidiospores, hyaline basidiospores, and most
pigmented deuteromycetes grouped together as might be expected,
but Pithomyces grouped closer to the colored basidiospores than with
the rest of the deuteromycetes.
Sunday, 8:15 am
Primary tissue and its role in the development
of the podetium in Cladonia
Samuel Hammer. Dept. of Organismic and Evolutionary
Biology and the Farlow Reference Library and Herbarium,
Harvard Univ., Cambridge, MA 02138.
The meristematic primary tissue detexmines morphological character-
istics of podetia in the genus Cladoniu. The primary tissue is purely
fungal, lacking dim? &hlar contact with the algal host, and it is
present at apical portions of podetia from their inception through
maturity. By tracing the development of the primary tissue, which is
presumed to be homologous in species of Ckulonia, podetial ontogeny
is clarified, and mature podetia can be compared without the inter-
ference of variability. This provides the opportunity for re-anlalyzing
relationships within the genus, particularly among taxa that have
previously been chemically circumscribed.
S a
Poster El; Sunday pm
Underground structures in Cladonia
. Dept of Organismic and Evolutionary
Biology and the Farlow Reference Library and Herbarium,
Harvard Univ., Cambridge, MA 02138.
Species of CIadaiu produce massive fungal structures beneath the sur-
face of the substratum. some of which are wrsistent wen in mature,
photosynthetically a&ve thalli. The stru&es may be broadly consi-
dered either as rhizomorphs or sclerotia, and they appear to dwelop in
stages, beginning as distinct hyphae and later conglomerating. They
are characterized by the secretion of extracellular substances which
bind the hyphae to one another and to the substratum, and in some of