Phylogeny and classification of Cryptodiscus, with a taxonomic synopsis of the Swedish species.

2009·0.61 MB·

by  Baloch, E

Fungal Diversity

Phylogeny and classification of Cryptodiscus, with a taxonomic synopsis of the
Swedish species

Baloch, E.1,3*, Gilenstam, G.2 and Wedin, M.1

1Department of Cryptogamic Botany, Swedish Museum of Natural History, P.O. Box 50007, SE-104 05 Stockholm,
Sweden.
2Department of Ecology and Environmental Sciences, Umeå University, SE-901 87 Umeå, Sweden.
3Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK.

Baloch, E., Gilenstam, G. and Wedin, M. (2009). Phylogeny and classification of Cryptodiscus, with a taxonomic
synopsis of the Swedish species. Fungal Diversity 38: 51-68.

The phylogeny, taxonomy and classification of Cryptodiscus are examined. The current generic and species
delimitations, and the relationship of the genus within the Ostropomycetidae, are tested by molecular phylogenetic
analyses of the nuclear ITS and LSU rDNA and the mitochondrial SSU rDNA. In our new circumscription
Cryptodiscus is a monophyletic group of saprotrophic and lichenized fungi characterized by small, urceolate apothecia,
mostly hyaline ascomatal walls without any embedded crystals, no clear periphysoids, and with oblong to narrow-
cylindrical septate ascospores. Cryptodiscus forms a well-supported clade together with Absconditella and the
remaining Stictidaceae. Paschelkiella and Bryophagus are synonymised with Cryptodiscus. Species excluded from
Cryptodiscus are Cryptodiscus anguillosporus, C. angulosus, C. microstomus, and C. rhopaloides. Cryptodiscus in
Sweden is revised and six species are accepted, of which one is newly described: C. foveolaris, C. gloeocapsa comb.
nov. (≡ Bryophagus gloeocapsa), C. incolor sp. nov., C. pallidus, C. pini comb. nov. (≡ Paschelkiella pini), and the
rediscovered species C. tabularum. The additional new combinations Cryptodiscus similis comb. nov. and C.
minutissimus comb. nov. are coined for the remaining former Bryophagus species. Lectotypes are designated for
Bryophagus gloeocapsa Arnold, Odontotrema pini Romell and Stictis foveolaris Rehm.

Key words: Ascomycota, discomycetes, lichens, molecular phylogeny, Ostropomycetidae

Article Information
Received 14 November 2008
Accepted 26 March 2009
Published online 1 October 2009
*Corresponding author: Elisabeth Baloch; e-mail: [email protected]

Introduction listed in Saccardo’s Sylloge Fungorum
(Saccardo, 1889; Saccardo and Sydow, 1899,
Cryptodiscus (Stictidaceae, Ostropomy- 1902; Saccardo and Trotter, 1913; Saccardo et
cetidae, Lecanoromycetes) is a group of small al., 1928), many of which are only known from
and inconspicuous discomycetes, most of fragmentary or lost type material. Additional
which are saprotrophs on dead wood. This species are C. sambuci (USA; Cash, 1943),
cosmopolitan genus comprises only a few C. tabularum (Germany; Kirschstein, 1936),
currently accepted species, but these fungi are C. rutilus (Germany), which was originally
rarely collected and studied and our knowledge described as Calonectria (Kirschstein, 1939)
is thus very limited. In the latest monograph of and recombined by Rossman (1979; 1980), and
Cryptodiscus, Sherwood (1977) accepted six C. anguillosporus (Sweden), which was newly
species; C. pallidus (type species), C. foveo- described by Holm and Holm (1981).
laris, C. microstomus, C. pumilus, C. stereicola Species of Cryptodiscus have been
and C. speratus. The three last ones are described from decaying palm fronds, lycopods
temperate and tropical American species that and the polypore Stereum sp., but most species
were described as new by Sherwood. She occur on weathered decorticated wood of va-
commented only on some of the ca. thirty rious trees. Traditionally Cryptodiscus includes
additional species described at that time and saprotrophic species with ascomata immersed
51
in the substrate, which become erumpent in species as well as species that need to be
some taxa. The margin is thin and somewhat combined into this genus. For this reason the
indistinctive, the disc deeply urceolate. The taxonomy and nomenclature of the Swedish
asci are 8-spored and cylindrical-clavate, the species of Cryptodiscus are revised, based on
spores hyaline, one- to pluriseptate, and the both morphological and molecular studies.
paraphyses simple, sometimes forked at the Information on substrate specificity and
end. ecological preferences of Swedish species is
The classification of Cryptodiscus and interpreted based on field experience, own
other Stictidaceae has varied over time. Minks collections and herbarium material studied.
(1881) and Lettau (1937) were early to suggest
a relationship between saprotrophic Stictida- Materials and methods
ceae with the lichenized Gyalectaceae. This
was mainly due to the superficial resemblance Specimens
of the ascomata between Stictis stellata and We analysed mainly fresh material
some Gyalectaceae, but also due to the similar collected in different areas of Sweden and
development of the ascomata. Mycologists supplemented own collections with herbarium
later assumed that the Stictidaceae are related material from the herbaria K, S, and UPS
to other ascomycete groups e.g. Clavicipitales (abbreviations according to Holmgren and
(Gäumann, 1964; Kreisel, 1969). Korf (1973) Holmgren, 1998; http://sweetgum.nybg.org/ih/).
and Dennis (1978) included Cryptodiscus in Examined types and specimens used for
the Dermateaceae (Helotiales) separate from microscopic studies are listed following the
the other Stictidaceae. Vĕzda (1966) suggested species description. We collected eight species
that Stictidaceae might be more closely related of Cryptodiscus in Sweden and sequenced
to the lichenized Thelotremataceae, agreed on twenty specimens of Cryptodiscus and one of
by Gilenstam (1969) and Henssen and Jahns Absconditella lignicola for this project. Vou-
(1974) and later confirmed by molecular cher details are given in Table 1. Additional
phylogenetic results (Winka et al., 1998). In sequences of Cryptodiscus and other genera
the first molecular phylogenetic study that that were used in the phylogenetic analyses
included Cryptodiscus, the single analysed were taken from GenBank and are listed in
species C. foveolaris did not group with other Table 2.
members of Stictidaceae, but rather with
Thelotrema (Wedin et al., 2005). Stictidaceae Microscopic studies
and Graphidaceae (including Thelotremata- For routine identification sections were
ceae; Mangold et al., 2008) are currently cut by hand with a razor blade. Sections with
included in the Ostropales in the Ostropomyce- the freezing microscope were used for detailed
tideae (Lumbsch et al., 2007; Hibbett et al., studies of the anatomy. Measurements of
2007), but the delimitation of this order is spores, asci, hymenium and details of the
admittedly rather unclear (Tehler and Wedin, apothecial wall were done in water. Lugol’s
2008). solution was used for the detection of amyloid
In the present study, we attempted to structures. Several sections of each species
include as many Swedish representatives of were stained with cotton blue in lactic acid to
Cryptodiscus as possible and in addition a enhance the contrast for a better observation of
selection of other Ostropomycetidae, into an hyphal structures.
updated molecular phylogeny. The aim is to
analyse the phylogenetic position of Cryptodis- DNA extraction, PCR and sequencing
cus within the Ostropomycetidae, to test the Total DNA was extracted from
current generic concept and delimitation, and apothecial tissue with the DNeasy Plant Mini
to investigate species boundaries. The Kit (Qiagen) according to the instructions of
relationship of saprophytic Cryptodiscus the manufacturer. The small subunit of the
species with lichens will be discussed. Our mitochondrial rDNA (mtSSU) was amplified
field studies focussing on ostropalean fungi in with the primers mrSSU1 and mrSSU3R
Sweden revealed an undescribed Cryptodiscus (Zoller et al., 1999) and the internal transcribed
52
Fungal Diversity

Table 1. Voucher specimens sequenced for this study with collections details and accession
numbers of the sequences.

Species Specimen mtSSU nuLSU
Absconditella lignicola EB211 Sweden, Östergötland, Svensson 941 (priv. FJ904691 FJ904669
Herb. Svensson)
Cryptodiscus foveolaris EB86 Sweden, Södermanland, Baloch SW072 (S) FJ904692 FJ904670
C. foveolaris EB88 Sweden, Lule Lappmark, Gilenstam 2719 (UPS) FJ904693 FJ904671
C. foveolaris EB147 Sweden, Lule Lappmark, Gilenstam 2776 (UPS) FJ904694 FJ904672
C. foveolaris EB155 Sweden, Skåne, Baloch SW168 (S) FJ904695 FJ904673
C. gloeocapsa EB93 Sweden, Jämtland, Tibell 23543 (UPS) FJ904696 FJ904674
C. incolor EB164 Sweden, Skåne, Baloch & Arup SW138 (S) FJ904697 FJ904675
C. microstomus EB185 Sweden, Lycksele Lappmark, Gilenstam 2784a FJ904698 FJ904676
(UPS)
C. pallidus EB40 Sweden, Lycksele Lappmark, Gilenstam 2694 FJ904699 FJ904677
(UPS)
C. pallidus EB60 Sweden, Skåne, Læssøe SW012 (S) FJ904700 FJ904678
C. pallidus EB152 Sweden, Lycksele Lappmark, Gilenstam 2475 FJ904701 FJ904679
(UPS)
C. pallidus EB173 Sweden, Östergötland, Baloch SW174 (S) FJ904702 FJ904680
C. pini EB76 Sweden, Småland, Westberg SW137 (S) FJ904703 FJ904681
C. pini EB82 Sweden, Östergötland, Baloch SW069 (S) FJ904704 FJ904682
C. pini EB178 Sweden, Uppland, Wedin & Baloch 26VII07 (S) FJ904705 FJ904683
C. pini EB181 Sweden, Skåne, Baloch & Arup SW175 (S) FJ904706 FJ904684
C. rhopaloides EB100 Denmark, Jylland, Læssøe 12881 (S) FJ904707 FJ904685
C. tabularum EB62 Sweden, Lycksele Lappmark, Gilenstam 2759 FJ904708 FJ904686
(UPS)
C. tabularum EB77 Sweden, Småland, Westberg SW136a (S) FJ904709 FJ904687
C. tabularum EB87 Sweden, Uppland, Baloch SW073 (S) FJ904710 FJ904688
C. tabularum EB169 Sweden, Bohuslän, Westberg SW132 (S) FJ904711 FJ904689
C. tabularum CO205 Sweden, Gilenstam 2641a (UPS) FJ904712 FJ904690

spacer (ITS) and parts of the nuclear large edited using the STADEN Package (http://
subunit rDNA (nuLSU) were amplified using www.mrc-lmb.cam.ac.uk/pubseq).
the primers ITS1F (Gardes and Bruns,1993)
and LR3 (Vilgalys and Hester, 1990). Biotech Alignment and Data analysis
Ready-To-GoPCR Beads (Amersham Pharma- The nucleotide sequences were aligned
cia) were used for PCR. The conditions for the with the multiple sequence alignment option in
thermocycling were 94 °C (3 min), six cycles the program Clustal W (Thompson et al., 1994).
of 94°C (45 s), 56−51°C (45 s), 72°C (1 min 30 We assembled two different data sets, one to
s), 35 cycles of 94°C (30 s), 48°C (30 s), 72°C optimally investigate the systematic position of
(1 min), and a final extension of 72°C (5 min). the different Cryptodiscus species within the
PCR products were cleaned using Qiaquick Ostropomycetidae and another one to analyse
spin columns (Qiagen). Both complementary the genetic variation and relation of the
strands were sequenced with the ABI BigDye Cryptodiscus species s.str. The first dataset
Terminator Kit (Applied Biosystems). For comprises sequences of Cryptodiscus species
sequencing of the ITS/nuLSU fragment the and representatives of all major lineages of
primer ITS4 (White et al., 1990) and LR0R Ostropomycetidae that were available in
(Rehner and Samuels, 1994) were used in GenBank. Four species of Lecanoromycetidae
addition to the PCR primers, in case of the were used as outgroup taxa. In the second
mtSSU fragment the same primers as for the dataset we included members of Cryptodiscus
PCR were applied. The sequencing products s.str. represented by several specimens per taxa
were cleaned with the DyeEx 96 Kit (Qiagen) (except C. incolor), Absconditella species as
and were run on an ABI3100 automated closest relatives to Cryptodiscus and three
sequencer. The raw data were assembled and species of Stictis and Schizoxylon as outgroup
53
Table 2. Additional sequences taken from Bayesian Metropolis coupled Markov
GenBank to include in the phylogenetic chain Monte Carlo (B/MCMCMC) analyses
analyses. were performed in the program MrBayes
Version 3.1.2 (Huelsenbeck and Ronquist,
Species mtSSU nuLSU 2001, Ronquist and Huelsenbeck, 2003). Each
Absconditella sphagnorum AY300872 AY300824 analysis was performed using two independent
Absconditella sp. AY300873 AY300825 runs with five chains running for 2000000
Aspicilia caesiocinerea DQ986892 DQ986778 generations. Trees were sampled every 100th
Baeomyces placophyllus AY584695 AF356658
generation. After 2000000 generations the
Calenia monospora AY341365 AY341351
Cladonia rangiferina AY300881 AY300832 average standard deviation of the split
Coenogonium pineti AY300884 AY300834 frequencies between the simultaneous runs was
C. leprieurii AY584698 AF465442 below 0.005 and the log-likelihood had reached
Conotrema urceolatum AY661676 AY661686
stationarity. 25% of the sampled trees were
Cryptodiscus foveolaris AY661673 AY661683
discharged as burnin. The frequencies of topo-
C. gloeocapsa AY300880 AF465440
Diploschistes scruposus AY584692 AF279389 logies in the resulting tree sample represent the
Echinoplaca epiphylla AY648891 AY341354 posterior probability of the branching patterns
Fissurina marginata AY648902 AY640012 (Huelsenbeck and Bollback, 2001). The
Glyphis cicatricosa AY648903 AY640025
general time reversible model (GTR) using a
Graphis scripta AY853322 AY853370
gamma shaped distribution and proportion of
Gyalecta jenensis AY340493 AF465450
G. ulmi AY300888 AF465463 invariant sites was suggested as the best DNA
Gyalidea hyalinescens DQ972996 DQ973046 substitution model for each gene (mtSSU and
Lecanora polytropa DQ986807 DQ986792 nuLSU or ITS-nuLSU) for both datasets. This
Ochrolechia tartarea AY300899 AY300848
was evaluated with the help of the program
Odontotrema sp. 1 AY661674 AY661684
MrModeltest (Nylander, 2004), which is a
Odontotrema sp. 2 AY661675 AY661685
Pertusaria amara AY300900 AF274101 reduced version of Modeltest (Posada and
Phlyctis argena DQ986880 DQ986771 Crandall, 1998).
Phyllobaeis erythrella DQ986888 DQ986780
P. imbricata DQ986895 DQ986781
Results and discussion
Physcia aipolia DQ912290 DQ782904

Placopsis perrugosa AY584716 AF356660
DNA sequences and alignments
Pyxine sorediata DQ972984 DQ973036
Sagiolechia rhexoblephara AY853341 AY853391 The first alignment with representatives
Schizoxylon albescens AY661680 AY661689 of Ostropomycetidae resulted in a matrix of
Stictis populorum AY527363 AY527334 2456 nucleotide positions (mtSSU 1009/nu
Stictis radiata AY300914 AY300864
LSU 1447), of which 1128 indel and ambi-
Thelotrema lepadinum AY300916 AY300866
guous aligned positions were excluded. Of the
Trapelia placodioides AF431962 AF274103
Trapeliopsis granulosa AF381567 AF274119 1328 included characters (mtSSU 640/nuLSU
688) were 609 parsimony informative (mtSSU
taxa. Separate and combined analyses of 315/nuLSU 294). The second alignment in-
mtSSU and nuLSU (first dataset) or ITS- cludes 20 sequences of Cryptodiscus, three
nuLSU (second dataset) sequences were Absconditella species and three other Stictida-
performed using Bayesian inference as well as ceae as outgroup taxa. The alignment has 2394
a maximum parsimony approach. Maximum (mtSSU 1240/ITS-nuLSU 1154) nucleotide
parsimony analyses were performed using position, of which 762 indel and ambiguously
PAUP* 4.0b10 (Swofford 2004). Gaps were aligned positions were excluded prior analysis.
treated as missing data. For each run a heuristic The included 1632 nucleotide positions
search with 1000 random-addition sequence (mtSSU 688/ITS-nuLSU 944) comprise 436
replicates was applied using tree bisection- parsimony informative characters (mtSSU
reconnection (TBR) branch-swapping, with 215/ITS-nuLSU 221).
MulTrees on and the steepest descent option Separate analyses of two gene regions
not in effect. Bootstrap supports were esti- result in tree topologies that are concordant in
mated with 1000 replicates and 10 random strongly supported branches (>70% bootstrap
sequence additions per bootstrap replicate with (bs), >95% posterior probability (pp)). The
the same search parameters as above. mtSSU rDNA analysis, however, provides a far
54
Fungal Diversity

Calenia monospora
100/100
-/100 Echinoplaca epiphylla
Gyalidea hyalinescens
‘Cryptodiscus’ rhopaloides
Gyalecta jenensis
Phlyctis argena
Graphis scripta
54/95
Thelotrema lepadinum
59/100
Glyphis cicatricosa
75/83 Diploschistes scruposus
75/86
Fissurina marginata
Coenogonium pineti
100/100
Coenogonium leprieurii
Gyalecta ulmi
Sagiolechia rhexoblephara
Cryptodiscus foveolaris
94/100
54/- Cryptodiscus tabularum
63/100 Cryptodiscus (Bryophagus) gloeocapsa
99/100
Cryptodiscus pallidus
Stictidaceae
100/100 Cryptodiscus incolor
100/100 Cryptodiscus (Paschelkiella) pini
93/100 Absconditella lignicola
Absconditella sphagnorum
100/100
Absconditella sp
96/100
Stictis radiata
94/100 74/96
Conotrema urceolatum
Stictis populorum
-/92 88/100 Schizoxylon albescens
82/100
Odontotrema sp. 1
100/100
Odontotrema sp. 2
60/97 ‘Cryptodiscus’ microstomus
Trapelia placodioides
Ostropomycetidae
100/100 Placopsis perrugosa
82/100
Trapeliopsis granulosa
Phyllobaeis imbricata
100/100
Phyllobaeis erythrella
100/100
100/100 Baeomyces placophyllus
Ochrolechia tartarea
61/52
99/100 Pertusaria amara
90/100 Aspicilia caesiocinerea
Pyxine sorediata
99/100 Physcia aipolia
Lecanora polytropa
Cladonia rangiferina
10

Fig. 1. Cryptodiscus within Ostropomycetidae. One of 3 most parsimonious trees inferred from mitochondrial SSU and
nuclear LSU rDNA sequence data. Bootstrap supports and posterior propabilities (bs/pp) are indicated next to the node.

better resolution than the nuLSU rDNA Cryptodiscus foveolaris and C. tabularum. This
analysis which to some extent was unresolved. is only supported by the mtSSU data (bs=78),
We will thus only discuss the combined but not the nuLSU, which resulted in a 74%
analyses (mtSSU + nuLSU) below and bootstrap support in the combined analysis (Fig.
comment on the few differences there are. 2a). In the Bayesian tree B. gloeocapsa groups
Although the separate gene trees are congruent, with C. pallidus and Paschelkiella pini,
the maximum parsimony and the Bayesian however with low support in the single gene
analyses differ in terms of the position of analyses (mtSSU: pp=88, nuLSU: pp=86,
Bryophagus gloeocapsa. In the maximum combined: pp=99) (Fig. 2b).
parsimony analysis B. gloeocapsa is sister to
55
Cryptodiscus tabularum EB62
C. tabularum EB77
63
a. Maximum parsimony C. tabularum EB169
100
C. tabularum CO205
C. tabularum EB87
100
86 C. foveolaris EB147
100 C. foveolaris GenBank
74
C. foveolaris EB86
9
C. foveolaris EB155
100 C. gloeocapsa GenBank
C. gloeocapsa EB93
99 C. pallidus EB40
100 C. pallidus EB60
C. pallidus EB152
89
C. pallidus EB173
C. incolor EB164
100 100
C. pini EB82
71
C. pini EB178
100 100 C. pini EB181
C. pini EB76
Absconditella lignicola
89
100 Absconditella sphagnorum Cryptodiscus pallidus UM40
Absconditella sp 100 C. pallidus EB60
Stictis radiata C. pallidus EB152
Stictis populorum
C. pallidus EB173
83
Schizoxylon albescens
C. pini EB82
10
98
C. pini EB178
100
C. pini EB181
100
C. pini EB76
99
C. incolor EB164
100 C. gloeocapsa GenBank
C. gloeocapsa EB93
b. Bayesian analysis
C. tabularum EB62
97 99
C. tabularum EB77
99
C. tabularum EB169
100
C. tabularum CO205
C. tabularum EB87
100 100
100 C. foveolaris EB147
100 C. foveolaris CO87
C. foveolaris EB86
100
100
C. foveolaris EB155
Absconditella lignicola
100 Absconditella sphagnorum
Absconditella sp
100 Schizoxylon albescens
Stictis populorum
Stictis radiata
0.1
Fig. 2. Phylogeny of Cryptodiscus sensu stricto. a. Most parsimonious trees inferred from a combined analysis of
mitochondrial SSU and nuclear ITS-LSU rDNA sequence data. Bootstrap supports above 50% are indicated next to the
node. b. 50% Majority-rule consensus tree of 421000 trees from a B/MCMC tree sampling procedure analysing the
same dataset as in a. Posterior probabilities are indicated next to the node.

56
Fungal Diversity

Cryptodiscus within Ostropomycetidae hepatics. It is clearly a common phenomenon
Cryptodiscus s.str. forms a monophyletic in Stictidaceae that closely related taxa vary in
clade with strong support (bs=99, pp=100), lifestyle; in Stictis, even the same species may
including the genera Paschelkiella and be either weakly lichenized or saprotrophic
Bryophagus, which are nested within Crypto- (Wedin et al., 2004; 2006). Although B.
discus. Absconditella is supported as gloeocapsa was the only Bryophagus species
paraphyletic with Absconditella lignicola as the for that we could obtain fresh material, the
sister taxon of Cryptodiscus (bs=100, pp=100). morphological characters of the other species
Absconditella sphagnorum, the type of Abscon- currently classified in this genus are fully
ditella, forms the sister group to Cryptodiscus consistent with a reclassification within
and A. lignicola (bs=93, pp=100) together with Cryptodiscus. We thus coin the relevant com-
an unidentified but closely related Abscon- binations below.
ditella. Vĕzda and Pisút (1984) provided Paschelkiella is a monotypic genus that
detailed studies on the development of the asci is nested within Cryptodiscus in our analysis
in A. lignicola and concluded that no characters (Fig. 1). Paschelkiella pini was originally
contradict the classification of Absconditella in described as Odontotrema pini. The erumpent
the Stictidaceae. Sherwood (1977) suggested ascomata with dark brown margins (Fig. 3e)
that Absconditella is morphologically and look superficially very much like an Odon-
anatomically very close to Cryptodiscus, which totrema. The non-carbonated wall of the
was also mentioned by Spribille et al. (2009). apothecia convinced Sherwood-Pike (1987),
Nevertheless we hesitate to include Abscon- however, that this species could not be
ditella in Cryptodiscus as there are slight congeneric with Odontotrema. She thus des-
differences in appearance of the ascomata and cribed the new genus Paschelkiella, and noted
in thickness and structure of the ascomatal wall that it had an intermediate position between
in some species of Absconditella. The Odontotrema and Cryptodiscus. As P. pini is
phylogenetic distance of A. sphagnorum to nested within Cryptodiscus in our analyses and
Cryptodiscus s.str. is already quite substantial. the anatomic details of this species are
Additionally, the position of the remaining consistent with other Cryptodiscus species, we
Absconditella species seems to be rather suggest transferring it to this genus below.
unpredictable. Before taxonomic decisions can As can be seen in Fig. 1, Cryptodiscus
be made, a larger number of Absconditella forms a monophyletic group together with
species need to be analysed together with a Absconditella, two yet undescribed Odontotre-
comprehensive comparative study of Abscondi- ma (s. lat.) species and Stictidaceae s.str. We
tella and Cryptodiscus. propose that this whole clade is treated as the
The lichenized fungus Bryophagus family Stictidaceae.
gloeocapsa, the type species of Bryophagus, is ‘Cryptodiscus’ rhopaloides does not
nested within Cryptodiscus, and as a result, group with Cryptodiscus. Based on morpho-
Bryophagus should be treated as a synonym to logical and anatomical observations already
Cryptodiscus. Morphology and general ap- Dennis (1981) stated that C. rhopaloides “is
pearance support the relationship. Like not a good Cryptodiscus, but has affinities
Cryptodiscus, Bryophagus has yellowish, rather with Melittosporiella and may eventual-
ochraceous to orange coloured ascomata with ly be transferred to Karstenia”. The ascomatal
deeply concave discs (Fig. 3b), and hyaline wall and the conspicuous periphysoids, a
ascomatal walls without clear periphysoids. character not found in Cryptodiscus s. str., as
The development of the ascomata follows the well as the close resemblance with Karstenia
typical ostropalean ontogeny and young idaei convinced Baral (http://wwkk.mikologia.
ascomata are at the beginning closed and pl/files/fos1errata.doc) to agree with Dennis
spherical, with punctiform openings that widen (1981). At present we do not assign this taxon
with maturation. Bryophagus species mainly to a genus since further studies are needed. It is
differ from saprotrophic Cryptodiscus species certain that ‘C.’ rhopaloides is within the
in that they are lichenized and grow on monophyletic clade comprising Graphidales,
different substrates like mosses, soil and Gyalectales, Stictidaceae, and Trichotheliales,
57
Fig. 3. Habit of the six Cryptodiscus species in Sweden. a. C. foveolaris (Baloch SW126, S), b. C. gloeocapsa (Tibell
23543, UPS), c. C. incolor (Baloch & Arup SW138, S), d. C. pallidus (Gilenstam 2475, UPS), e. C. pini (Westberg
SW199, S), f. C. tabularum (Gilenstam 2641a, UPS).

but like a number of other taxa it cannot be Cryptodiscus or the Stictidaceae. Unlike ‘C.’
assigned to any of these orders. We had no rhopaloides, C. microstomus was accepted in
fresh material of a Karstenia available to Cryptodiscus by Sherwood (1977). She noted
include in our sampling, but ‘Cryptodiscus’ in her description that the type and only
rhopaloides might be closely related to or examined specimen “may be slightly im-
congeneric with Karstenia. mature”. We were able to collect this species
Our results also suggest the exclusion of several times in Sweden. Younger apothecia of
C. microstomus as it did not group near our specimens are identical to the type of
58
Fungal Diversity

C. microstomus. When maturating, the overall weathered decorticated wood that often is
appearance of the ascomata changes and the moist but still firm. Cryptodiscus pallidus
ascomatal wall becomes much darker, but seems to prefer wood of deciduous trees and
microscopical characters leave no doubt that has mostly been found on Populus and Salix,
our Swedish specimens are conspecific with but it has also been collected on Fagus, Rosa,
the type of C. microstomus. Cryptodiscus and once on well weathered wood of Juniperus.
microstomus belongs to the subclass Like other species it can occur on decorticated
Ostropomycetidae and as shown in our results branches still attached to the tree, or on logs
is the sister taxon of the monophyletic lying on the ground. Cryptodiscus foveolaris is
Graphidales-Gyalectales-Stictidaceace-Tricho- the least host specific species. It grows on a
theliales clade (Fig. 1). Presumably it is outside large variety of different trees, both deciduous
of this clade and its closest relatives still need trees and conifers. We assume that
to be found. C. foveolaris is less demanding concerning the
moistness of the substrate and/or the quality of
Cryptodiscus sensu stricto
the wood, compared to C. pallidus, which
In the second dataset we included a larger
would explain the wider host diversity. Both
number of samples of the collected species that
species were frequently collected on dead
ended up in Cryptodiscus s. str. Here, the
wood in forests, but their occurrence in one
relationship and the delimitation of the species
locality is usually rather scattered.
within Cryptodiscus s. str. were investigated.
In Sweden C. tabularum and C. pini have
We have been able to identify six mor-
only been collected on pine wood. Both species
phologically well-circumscribed phylogenetic
are relatively frequent in more mature pine
species within Cryptodiscus s. str., which are
forests, and in the central and southern parts of
further fully congruent between the mtSSU and
Sweden they were often found at the same
ITS-nuLSU rDNA datasets (phylogenetic
localities. In suitable habitats they can be even
species recognition; Taylor et al., 2000, Grube
abundant. Cryptodiscus pini is known from
and Kroken, 2000). The separate analyses of
Scandinavia, Scotland, and western North
mtSSU and ITS-nuLSU rDNA are not shown
America, where it was collected on cultivated
here; the resulting trees of the combined
Libocedrus (Sherwood-Pike, 1987). Cryptodis-
analyses are presented in Fig. 2.
cus tabularum has been collected in Scotland,
The included species form two highly
Sweden and southern Germany. The type
supported clades. One clade includes C. pal-
specimen grew on a board of a shed composed
lidus, C. pini, and the sole specimen of C.
of weathered conifer wood, (presumeably
incolor, and in the other clade C. tabularum
spruce or larch but not pine wood), all other
and C. foveolaris form a group (bs=100,
specimen were collected on Pinus sylvestris.
pp=100). Although C. gloeocapsa is highly
Unlike C. tabularum, C. pini has not been
supported within Cryptodiscus, its relationship
documented from northern Sweden and it is
with other Cryptodiscus species is unclear (see
possible that its distribution does not extend as
above and Fig. 2). Interestingly, the two
far north as C. tabularum does. Finally, the
species with one-septate spores (C. pini and C.
sole specimen of C. incolor was collected on a
foveolaris) do not group together, but both are
wet log of a deciduous tree in southern Sweden.
more closely related to species with multi-
In general, all Cryptodiscus species are
septate spores. Cryptodiscus tabularum super-
inconspicuous and have been collected only by
ficially similar to C. pallidus with which it has
a few mycologists. Cryptodiscus tabularum,
been confused (see note under C. tabularum),
although it is certainly widespread and rela-
is clearly a distinct species and not even sister
tively common in Sweden, has for instance not
to C. pallidus.
been deposited in the herbaria of Lund (LD)

and Uppsala (UPS). In Stockholm (S) two
Comments on ecology and distribution of
specimens of C. tabularum have been found
Swedish species
among the rich C. pallidus collections. We
Except one lichenized species, all the
estimate that it is highly probable that new
Swedish Cryptodiscus species are saprotrophs
species of this genus could be discovered in
on wood. In general the species grow on
59
other climate zones and different parts of the margin hyaline or brownish, entire, no proper
world. periphysoids, sometimes short-celled hyphae
without clear direction can be observed on
Key to the species of Cryptodiscus s. str. in inner side of excipulum, mostly no
Sweden differentiation into layers; subhymenium thin
and small celled; hymenium concave, I+
1. Growing as a lichen on dead mosses or soil............... reddish-brown to I- and KOH/I+ blue (Lugol);
...............C. gloeocapsa (≡Bryophagus gloeocapsa)
asci cylindrical to somewhat clavate, 8-spored;
1. Growing as a saprobe on decorticated wood............2
ascus wall usually KOH/I+ faintly blue (Lugol);

2. Ascospores 1-septate................................................3 tholus present, no apical structures visible in
2. Ascospores 3-septate, or more.................................4 KOH/I; ascospores hyaline, ovate to narrowly
ellipsoid, transversely 1−7 (−9) -septate; para-
3. Ascomata pale, deeply immersed; disc ochraceous to
physes numerous, filiform, simple, sometimes
yellowish-orange; on wood of both conifers and
slightly forked in upper part, apices often
deciduous trees......................................C. foveolaris
3. Ascomata dark brown, becoming +/- erumpent when enlarged, sometimes knoblike; conidiomata
mature; disc pale brownish without orange tinge; on only observed in lichenized taxa, pycnidia
pine wood.....................C. pini (≡Paschelkiella pini) pyriform, immersed, conidia short-cylindrical.

Cryptodiscus can be distinguished from
4. Ascomata ca 0.1-0.2 mm diam; disc pale flesh
other ostropalean genera in that the species
coloured, almost hyaline............................C. incolor
4. Ascomata ca 0.2-0.5 (-0.8) mm diam; disc develop no distinct periphysoids, have more or
ochraceous to yellowish-orange...............................5 less hyaline ascomatal walls except in C. pini
without any embedded crystals, and have
5. Ascomata ellipsoid, seemingly splitting the substrate
comparatively short and few-celled ascospores.
lengthwise; disc pale ochraceous; spores 3-septate

and usually with constrictions at septa; usually on
wood of deciduous trees...........................C. pallidus Cryptodiscus foveolaris (Rehm) Rehm (1888)
5. Ascomata roundish, not splitting the substrate; disc Basionym: Stictis foveolaris Rehm (1881)
usually distinctly yellowish-orange; spores 3 (-7) Type: Rehm Ascom. 121; Germany, Sugenheim
septate, constrictions at septa only if spores have in Franken (Bavaria), on Quercus (S lectotype
more than 3 septa; on pine wood .........C. tabularum designated here)
= Stictis fagicola Phil. (1887)
Taxonomy of the Swedish Cryptodiscus s. str. Type: Britain, W. Phillips Elvellacei Britanici 200,
isotype (K) (Figs 3a, 5a)
Cryptodiscus Corda (1838) Apothecia round to ellipsoid, 0.2−0.3 mm
Type species: Cryptodiscus pallidus (Pers.) Corda diam, substrate often split slightly lengthwise
(1838; lectotype designated by Rehm, 1888) by ascomata, scattered to crowded; disc pale
= Bryophagus Arnold (1862)
ochraceous to orange coloured; margin hyaline
Type: Bryophagus gloeocapsa Arnold (1862)
to pale ochraceous, ca 25−50 µm thick,
= Gloeolecta Lettau (1937)
Type: Secoliga bryophaga Arnold (1864; strongly interwoven hyphae, no differentiation
=Bryophagus gloeocapsa Arnold, 1862) into layers (similar to C. tabularum, see Fig.
= Paschelkiella Sherwood (1987)
4d); hymenium 50−80 µm, I- and KOH/I+ blue;
Type: Paschelkiella pini (Romell) Sherwood
asci 50−65 × 4−5 µm; ascospores one-septate,
(1987)
Mycelium either saprotrophic and im- 6–9 × 2.5–3 µm, oblong; paraphyses 1 µm
mersed in dead, decorticated wood, or broad, enlarged to knoblike apex.
lichenized with a very thin gelatinous thallus; Substrate: on decorticated wood of deci-
in lichenized species photobiont Gloeocystis- duous trees (Betula sp., Corylus avellana,
like; apothecia round to ellipsoid, closed and Populus tremula, Quercus sp., Salix caprea)
immersed in substrate in early stages of and conifers (Picea abies, Pinus sylvestris).
development, apothecia eventually open by a Known distribution: Europe and North
round pore that widens to ± size of fruiting America; in Sweden it has been found in the
body, mostly persistently immersed in substrate, provinces Lule Lappmark, Lycksele Lappmark,
rarely erumpent in mature state; disc hyaline, Dalarna, Uppland, Södermanland, Östergötland
ochraceous, yellowish, pale orange or dark and Skåne. It can be frequent, but always
brownish, concave and immersed in substrate; scattered at its localities.
60