Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme II: SYSTEMATICS, PHYLOGENY AND EVOLUTION Posters
associated with Eucalyptus. Vascellum, Bovista, Calvatia,
and Dictyophora are common inhabitants of grass on
lawns, golf courses, and pastures. A pictorial summary of
the individual species will be presented.
680 - Population structure of Septobasidium curtisii, a
fungal symbiont of scale insects
D.A. Henk * & R. Vilgalys
Duke University, Box 90338 Durham, NC 27708, U.S.A. -
E-mail: dah@duke.edu
Septobasidium curtisii lives symbiotically with scale
insects on trees and is common in the southeastern United
States. The fungus forms thin black mats of hyphae over
colonies of scale insects infecting some but not all. Species
of Septobasidium are thought to disperse only as spores
infecting young scale insects, and subsequently, hyphae
from infected insects fuse to form a single fungal colony. If
this is true for S. curtisii then fungal colonies may be
genetic mosaics, and populations may be differentiated on
small spatial scales within a stand of trees or on a single
tree in accordance with host insect population structure. To
test these hypotheses we use DNA sequence data from
multiple loci to determine patterns of genetic diversity in
single colonies and across geographic and host ranges in S.
curtisii. Sequence data from five loci from single spore
isolates show that colonies are composed of a single
heterokaryotic individual that produces recombinant
spores. Preliminary data from collections across the
southeastern United States indicate that population
structure of S. curtisii and host insects are correlated but at
a larger spatial scale than expected.
681 - Puccinia hemerocallidis, cause of daylily rust, a
newly introduced disease in the Americas
J.R. Hernandez 1* , M.E. Palm Hernandez 2 & L.A.
Castlebury 1
1 USDA, Agricultural Research Service, Systematic Botany
and Mycology Laboratory (ARS, SBML), Rm. 304, B-011A,
BARC-West, Beltsville, MD 20705-2350, U.S.A. -
2 USDA/APHIS, Systematic Botany and Mycology
Laboratory, Rm. 329, B-011A, BARC-West, Beltsville, MD
20705-2350, U.S.A. - E-mail: jose@nt.ars-grin.gov
Daylilies (Hemerocallis spp.) are the most important
perennial flowering plant grown in the U.S. and are traded
extensively by hobbyists. A rust of daylilies was introduced
recently into North and Central America. Puccinia
hemerocallidis is known on daylilies in Asia (stages II, III)
with Patrinia (Valerianaceae) as the alternate host (stages
0, I), also native to Asia. Specimens from Costa Rica,
Japan, Russia and the United States as well as previously
collected specimens from its native eastern Asia were
examined morphologically to confirm that this rust was P.
hemerocallidis. In addition, the ITS region of the ribosomal
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Book of Abstracts
DNA was sequenced from six representative fresh
specimens from the Americas and Asia. The range of
variability of certain morphological characteristics,
including the ratio of non-septate to 1-septate teliospores,
was greater than indicated in the current literature.
Teliospore and urediniospore sizes varied among
specimens but statistical analysis indicated that there was
no significant difference in size between the Asian and the
American spores. Three synapomorphies (including one
indel) were present in the ITS region that distinguished the
two Asian specimens from the four American specimens.
However the ITS variation within the American or Asian
specimens was approximately equal to variation between
specimens from the two broad geographic areas. We
conclude that the rust introduced into the Americas is
Puccinia hemerocallidis.
682 - Exceptional morphological diversification in
Cladia and phylogenetic related lineages in Australasia
N. Hoffmann * & P.T. DePriest
Smithsonian Institution, Department of Botany, National
museum of Natural History, P.O. Box 37012 Washington,
DC 20013-7012, U.S.A. - E-mail:
nikolaus.hoffmann@kfunigraz.ac.at
Cladia is a genus of lichenized fungi with most of its
species endemic to the Australasian region. Of the 14
described species in the genus only four occur outside this
region. Three other lichen genera endemic to this region,
Heterodea, Ramalea and Thysanothecium, share many
anatomical features with Cladia, and its family
Cladoniaceae in general, but have very distinct vegetative
morphologies. In our phylogenetic analysis of three regions
of the nuclear and mitochondrial rDNA, the species of the
genus Cladia were divided into two clades. The first clade,
containing C. aggregata, the type species of the genus,
consisted exclusively of members of the C. aggregata
complex. This complex of very similar, hard to distinguish
species is characterized by rather irregular perforations and
a dark green-brown to black color. The second clade, in
some analyses a grade, includes regularly perforated
species of Cladia, such as C. ferdinandii and C. sullivanii.
The latter species are paraphyletic relative to Heterodea,
Ramalea and Thysanothecium. On the basis of this result
the name Cladia should be restricted to species of the
Cladia aggregata-complex; the correct generic names for
the remaining species requires further investigation. Our
phylogenetic hypothesis is consistent with the recent
diversification of these endemic 'genera' in Australasia.
Their previous treatment as separated genera reflects the
striking morphological evolution that has accompanied
their diversification.