Three new species of Oidiodendron Robak from Spain - CBS

CALDUCH ET AL.Nature Reserve. The Muniellos forest is located in thesouthwest of Asturias province (northern Spain). It hasa surface area of 5542 ha and an altitude ranging from650 to 1642 m. The average annual temperature is610 ºC and the annual mean rainfall is 14002300mm. The vegetation is composed of forests of Quercuspetraea (Matt.) Liebl., Q. pyrenaica Willd., Betulaceltiberica Rothm & Vasc., Fagus sylvatica L., riversideforests and mixed forests of Fraxinus excelsior L.and Acer pseudoplatanus L. (Fernández & Bueno1996).Table 1. List of names, strain numbers and accessionnumbers of the species analysed.Species Strain AccessionNo. EMBLOidiodendron cerealis (Thüm.) UAMH 1522 AF062788G.L. BarronO. chlamydosporicum Morall UAMH 6520 (T) AF062789O. citrinum G.L. Barron UAMH 1525 (T) AF062790O. echinulatum G.L. Barron IMI 110132 AF062791O. flavum Szilvinyi UAMH 1524 AF062792O. griseum Robak CBS 249.33 AF062793O. maius G.L. Barron UAMH 1540 (T) AF062798O. muniellense Calduch, IMI 391998 (T) AJ634700 1Stchigel, Gené & GuarroO. myxotrichoides Calduch, IMI 388795 (T) AJ635314Gené & GuarroO. periconoides Morrall DAOM 197506 (T) AF062802O. pilicola Kobayasi UAMH 7526 AF062787O. ramosum Calduch, Stchigel, IMI 391997 (T) AJ634701 1Gené & GuarroO. reticulatum Calduch, Stchigel,IMI 391999 (T) AJ634699 1Gené & GuarroO. rhodogenum Robak UAMH 1405 AF062803O. scytaloides Gams & SöderströmUAMH 6521 (T) AF062804O. setiferum Udagawa & UAMH 5715 (T) AF062805ToyazakiO. tenuissimum (Peck) Hughes CBS 238.31 (T) AF062807Oidiodendron sp. CBS 315.95 AF062806O. truncatum G.L. Barron UAMH 1399 (T) AF062809Myxotrichum arcticum Udagawa,UAMH 7565 AF062810Uchiyama & KamiyaM. cancellatum Phillips UAMH 1911 AF062811M. setosum (Eidam) Orr & UAMH 3835 AF062815PlunkettByssoascus striatosporus (G.L. UAMH 3572 (T) AF062817Barron & C. Booth) ArxGymnostellatospora japonica UAMH 8899 AF062818Udagawa, Uchiyama & KamiyaPseudogymnoascus roseus UAMH 9163 AF062819RailloAphanoascus keratinophilus IMI 319010 AJ133436Punsola & Cano1 Strains sequenced for this study. CBS = Centraalbureauvoor Schimmelcultures, Utrecht, The Netherlands; DAOM= Canadian collection of fungal cultures, Ottawa, Canada;IMI = International Mycological Institute, Egham, UnitedKingdom; FMR = Facultat de Medicina de Reus culturecollection, Spain; UAMH = University of Alberta microfunguscollection and herbarium, Edmonton, Alberta,Canada. (T) = ex-type culture.Soil samples were also collected in Gran CanariaIsland (Canary Islands), located in the Atlantic Ocean,to the north west of the African continent. This islandhas an area of 1532 km 2 and a maximum altitude of1949 m. It is of volcanic origin and mainly composedof basaltic terrain. The area is dominated by a temperateto subtropical climate, with an annual temperatureranging 1923 ºC at 200 m of alt, and from 1216 ºCat 1500 m. The annual mean rainfall is 150200 mm.Plant material and soil samples were processed asin Calduch et al. (2002) and Stchigel et al. (2001),respectively. The macro- and microscopic features ofthe fungi were studied on oatmeal agar (OA; 30 gflakes, 20 g agar, 1 L distilled water, home-made),potato-carrot agar (PCA; 20 g potatoes, 20 g carrots,20 g agar, 1 L distilled water, home-made) and potatodextroseagar (PDA; Difco Laboratories, Detroit,Michigan) at 15, 25 and 37 ºC under 12 h of darknessalternating with 12 h under cool white fluorescentlight. Colour notations in parentheses are fromKornerup & Wanscher (1984) (M. = Methuen). Photomicrographswere obtained under a Leitz Dialux 20light microscope and scanning electron images with aJeol JSM-6400 scanning electron microscope.Molecular studyIn addition to the sequences of the herein proposedOidiodendron species and that of O. myxotrichoidessequenced previously (Calduch et al. 2002), a total of21 sequences accessed from the GenBank belongingto other Oidiodendron species, Myxotrichum andByssoascus species with Oidiodendron anamorphs,and other members of Myxotrichaceae were includedin the molecular study (Table 1). Aphanoascus keratinophilus(AJ133436) was used as outgroup.Fungal DNA extraction, amplification and sequencingof the rDNA region were performed asdescribed in Solé et al. (2002). Fragments of 311320bp, comprising the 5.8S RNA gene (partial sequence),ITS2 (complete sequence) and 28S RNA gene (partialsequence), obtained with the primers ITS3 and ITS4were aligned using the Clustal X (version 1.81),computer programme for multiple sequence alignment(Thompson et al. 1997). We performed maximumparsimony analysis (MP), using the PAUP software(4.0 Beta version 10). Heuristic searches were conductedunder the following conditions: simple additionsequence with tree-bisection reconnection (TBR)branch swapping algorithm, starting trees obtained bystepwise addition, MULPARS option in effect, steepestdescent option not in effect, MAXTREES setting100, and branches having minimum length zero allowedto collapse yielding polytomies. Branch robustnesswas evaluated using 100 bootstrap replicates. Thesequences have been deposited in the European MolecularBiology Laboratories (EMBL).160

NEW SPECIES OF OIDIODENDRONTAXONOMYOidiodendron muniellense Calduch, Stchigel,Gené & Guarro, sp. nov. MycoBank MB500040.Figs 110.Etymology: Referring to the place where the funguswas collected.Ad Hyphomycetes pertinens. Coloniae in basidiomateputrido substrato naturali effusae, pilosae, olivaceobrunneaecoloratae. Hyphis pallide brunneis vel brunneis,septatis, 12 m latis. Conidiophora macronematosa,mononematosa, cum stipite simplici, recto, septato,brunneo, laevi, crassitunicato, usque ad 200 m longo,23.5 m lato ad basim, rami sursum in hyphas fertilesexeuntes; rami numero 46, identidem subdichotome veltrichotome ramosi, recti, septati, brunnei, acuti ad apicem,laevi et crassitunicati ad basim, leniter asperi ettenuitunicati ad apicem, usque ad 60 m longi, 1.52.5 mlati ad basim. Hyphae fertiles terminales vel laterales,ramosae, septatae, subhyalinae, laeves, cylindricae, 12.5m latae. Conidia sicca, catenata, unicellularia, globosa velsubglobosa, ochracea, rugosa vel echinulata, tenuitunicata,1.52.5 m diam. Teleomorphosis ignota.Figs 16. Oidiodendron muniellense (IMI 391998). 1. Colony growing on the natural substrate. 24. Conidiophores showingdistal fertile ramifications, bearing a central mass of arthroconidia. 5, 6. Arthroconidia. Scale bars: 1, 2 = 50 m, 3, 4 = 40 m,5 = 10 m, 6 = 5 m.161

CALDUCH ET AL.irregularly folded, with a darkening brown(M6D86F8) reverse. Colonies on PCA were 2630mm diam, olive-brown (M4E44F5), flat, velvety,with an olive-brown (M4E44F5) reverse. Colonieson PDA were 3740 mm diam, greyish orange togreyish brown (M5B35F3), slightly fasciculate at thecentre, radially folded, with a brownish orange toyellowish brown (M5C55F5) reverse. The fungusshowed good sporulation on the three culture mediamentioned. Microscopic features under these conditionsdid not vary from those on the natural substrate.At 15 ºC the fungus grew more slowly than at 25 ºCon all media assayed, with colonies attaining 1826mm diam after 14 wk. A diffusible brownish orange tobrown (M6C76D8) pigment was produced only onOA. No growth was observed at 37 ºC.Specimen examined: Spain, Asturias, Muniellos IntegralNature Reserve, on adecaying basidiome, 26 June 1999,col. A.M. Stchigel & M. Calduch, holotype IMI 391998,ex-type culture CBS 113932 = FMR 6765.Figs 710. Oidiodendron muniellense (IMI 391998). 7.Habit sketch. 8. Conidiophore. 9. Fertile hyphae bearingarthroconidia. 10. Arthroconidia. Scale bars: 7 = 50 m, 8,9 = 10 m, 10 = 2.5 m.Hyphomycetes. Colonies on the natural substrateeffuse, hairy, greenish brown. Mycelium partly immersedin the substrate. Hyphae pale brown to brown,septate, 12 m wide. Conidiophores macronematous,mononematous, each composed of a long stipe and arepeatedly branched upper part from where fertilehyphae are borne; stipe straight, septate, brown,smooth- and thick-walled, up to 200 m long, 23.5m wide at the base; upper part with 46 verticillatebranches, each branch several times subdichotomouslyor trichotomously branched, seta-like, straight, septate,brown, paling distally, smooth- and thick-walled,becoming roughened and thin-walled towards theapex, pointed at the tip, up to 60 m long, 1.52.5 mwide near the base. Fertile hyphae terminal or lateralon the dark hyphae of the conidiophore upper part,branched, septate, subhyaline, smooth-walled, cylindrical,12.5 m wide, fragmenting to form arthroconidia.Conidia dry, catenate, one-celled, globose tosubglobose, ochraceous, roughened (echinulate underSEM), thin-walled, 1.52.5 m diam. Teleomorphunknown.Cultural characteristics: The optimal colony growthwas at 25 ºC. At this temperature and after 4 wk ofincubation, colonies on OA were 3035 mm diam,brownish beige to brown (M6E36E8), flat, velvety,Notes: The present species is similar to O. hughesiiUdagawa & Uchiyama (Udagawa & Uchiyama 1998)and O. setiferum (Udagawa & Toyazaki 1987) in themorphology of the terminal part of the conidiophores.However, O. hughesii differs mainly by the developmentof a reticulum of dark olive-brown and conspicuouslyornamentated hyphae with spine-likeappendages at the periphery and by the production ofonly lateral fertile hyphae from the hyphal reticulum.The upper part of the conidiophore of O. setiferum ischaracterized by a subterminal whorl of dark brown,sterile setiform branches, which surrounds a terminalwhorl of subhyaline penicillate fertile hyphae. Moreover,conidia of O. muniellense are globose to subglobose,roughened and ochraceous, while those of O.setiferum and O. hughesii are ovoid to ellipsoidal, andsmooth-walled and brown, paler in the former, andasperate and hyaline in the latter.Oidiodendron ramosum Calduch, Stchigel, Gené& Guarro, sp. nov. MycoBank MB500041. Figs1122.Etymology: Referring to the branched conidiophores.Ad Hyphomycetes pertinens. Coloniae in basidiomateputrido, pilosae, olivaceo-brunneae coloratae. Hyphispallide brunneis vel brunneis, septatis, 1.52 m latis.Conidiophora macronematosa, mononematosa, cum stipitesimplici, recto, septato, brunneo, plerumque verrucoso,crassitunicato, usque ad 150 m longo, 23 m lato adbasim, rami sursum in hyphas fertiles terminantes; raminumero 26, subdichotomi, septati, longi recurvati, apicemversus attenuati, verruculosi vel verrucosi, pallidioresbrunnei ad basim, palliodore ad apicem, usque ad 130 m162

NEW SPECIES OF OIDIODENDRONlongi, 1.52.5 m lati ad basim. Hyphae fertiles terminalesvel laterales, ramosae, septatae, laeves, cylindricae, subhyalinae,11.5 m latae. Conidia sicca, catenata, unicellularia,subglobosa vel ellipsoidea, pallide brunnea, laevia velleniter rugosa, tenuitunicata, 1.53 12 m. Teleomorphosisignota.Hyphomycetes. Colonies on a decaying basidiome,hairy, greenish brown. Mycelium partly immersed inthe substrate. Hyphae pale brown to brown, septate,1.52 m wide. Conidiophores macronematous,mononematous, composed of a stipe bearing at theupper part a whorl of dematiaceous, fertile seta-likebranches which surrounds a dense head of fertilehyphae; stipe straight, septate, brown, verruculose,thick-walled, up to 150 m long, 23 m wide at thebase; upper part with 26 verticillate branches, eachbranch subdichotomously branched, seta-like, septate,broadly recurved, attenuate at the tip, verruculose toverrucose, pale brown and becoming subhyalinedistally, up to 130 m long, 1.52.5 m wide near thebase, from which fertile hyphae also develop. Fertilehyphae terminal or lateral on the dematiaceousbranches of the conidiophore upper part, but also onthe terminal portion of the conidiophore stipe, forminga dense whorl of penicillate hyphae, septate, smoothwalled,subhyaline, cylindrical, 11.5 m wide,fragmenting to form arthroconidia.Figs 1118. Oidiodendron ramosum (IMI 391997). 11, 12. Conidiophores on the natural substrate. 13. Detail of a conidiophoreapical part with fertile ramifications that surround arthroconidial masses. 14. Conidiophore in vitro. 15, 16. Penicillate fertilehyphae. 17, 18. Arthroconidia. Scale bars: 11, 12 = 100 m, 13 = 25 m, 14 = 50 m, 15, 17 =10 m, 16 = 5 m, 18 = 2.5 m.163

CALDUCH ET AL.Conidia dry, catenate, one-celled, subglobose toellipsoidal, pale brown, smooth to slightly roughened(roughened under SEM), thin-walled, 1.53 12m. Teleomorph unknown.Cultural characteristics: The optimal colony growthwas at 25 ºC. Colonies on OA were 2025 mm diamafter 4 wk, olive-brown (M4F8), with greyish margins,flat, powdery, concentrically radiate, with anolive-brown (M4D54E5) reverse. On PCA colonieswere 1820 mm diam after 4 wk, olive (M2F4) withwhitish margins, flat, velvety, with an olive (M2E4)reverse. On PDA, they were 2730 mm diam after 4wk, orange-white to greyish orange (M5A25B3),cerebriform, radially folded, with a greyish orange(M5B45B5) reverse. The microscopic features of thefungus did not vary from those observed on the naturalsubstrate. At 15 ºC the fungus grew slower (1317mm diam after 4 wk) and sporulation was poorer thanat 25 ºC on all the media assayed. No growth wasobserved at 37 ºC.Figs 1922. Oidiodendron ramosum (IMI 391997). 19.Habit sketch. 20. Conidiophore. 21, 22. Fertile hyphaebearing arthroconidia. Scale bars: 19 = 100 m, 20, 21 = 20m, 22 = 4 m.Specimen examined: Spain, Asturias, Muniellos IntegralNature Reserve, on an unidentified rotten basidiocarp, 26June 1999, coll. A.M. Stchigel & M. Calduch, holotypeIMI 391997, ex-type cultures CBS 113931 = FMR 6764.Notes: Oidiodendron setiferum (Udagawa & Toyazaki1987) is most similar to O. ramosum. Both have at the164upper part of the conidiophore stipe a dense head offertile hyphae surrounded by a whorl of dematiaceous,seta-like branches. However, in the former, thesebranches are sterile, while in O. ramosum they arefertile. Moreover, the conidia of O. setiferum aresmooth-walled and separated each other by thick anddark connectives. Oidiodendron muniellense alsoresembles O. ramosum in conidiophore morphology,but in the former the peripheral branches of the conidiophoreupper part are strainght and smoothwalled,becoming roughened distally. Additionally,the conidial morphology of O. muniellense is different.Oidiodendron reticulatum Calduch, Stchigel,Gené & Guarro, sp. nov. MycoBank MB500042.Figs 2335.Etymology: Referring to the morphology of the upperpart of the conidiophores.Ad Hyphomycetes pertinens. Coloniae in vitro 2225 ºCrestrictae, planae, olivaceo-griseae coloratae. Hyphis pallidebrunneis, septatis, 11.5 m latis. Conidiophora macronematosa,mononematosa, stipite simplici, reticulum globosumin parte apicale formantes et hyphis lateralibus fertilibus;stipites reticulum e ramis anastomosantibus, 90150m diam, ramis apicem versus attenuatis et rotundatis,septatis, fortiter verrucosis et spinulosis, brunneis, 560 mlongis, 23 m latis ad basim. Hyphae fertiles ex hyphisreticuloriundae, ramosae, septatae, laeves, subhyalinae velpallide griseo-brunneae, cylindricae, 515 m longis, 1.52m latae. Conidia sicca, catenata, unicellularia, ellipsoidea,pallide brunnea vel pallide olivaceo-brunnea, rugosa velechinulata, tenuitunicata, 1.54 1.52.5 m. Conidiophoraaltera simplicia; co-formantia, stipites recti, septati,leniter crassitunicati, pallide brunnei, usque ad 350 mlongi, 1.52.5 m lati ad basim; capitulum compactumhypharum fertilium ferentes. Teleomorphosis ignota.Hyphomycetes. Colonies in vitro at 2225 ºC restricted,plane, olive-grey in colour. Mycelium partlyimmersed in the substrate, composed of pale brown,septate, 11.5 m wide hyphae. Conidiophoresmacronematous, mononematous, of two types: i) astipe ending in a reticulate network of hyphae fromwhich lateral fertile hyphae are produced; stipestraight, septate, brown, smooth-walled to slightlyverruculose, thick-walled, up to 200 m long, 1.52.5m wide at the base, upper part several timesbranched and anastomosing to form a more or lessglobose reticulate network, measuring 90150 mdiam, with seta-like peripheral branches; branches ofthe reticulum recurved or sinuous, attenuate androunded at the tip, septate, strongly verrucose andspinulose throughout, brown, 560 m long, 23 mwide at the base; and ii) conidiophores simple, stipestraight, septate, slightly thick-walled, pale to brown,

NEW SPECIES OF OIDIODENDRONup to 350 m long, 1.52.5 m wide at the base,producing terminally a dense head of fertile hyphae.Fertile hyphae arising laterally from branches of thereticulum or terminally from the conidiophore stipe,branched, septate, smooth-walled, subhyaline to palegreyish brown, cylindrical, 515 m long, 1.52 mwide, fragmenting to form arthroconidia. Conidia dry,catenate, one-celled, pale brown to pale olivaceousbrown,roughened (echinulate under SEM), thinwalled,ellipsoidal, 1.54 1.52.5 m, with one orboth ends truncate. Teleomorph unknown.Cultural characteristics: The optimal colony growthwas at 25 ºC. Colonies on OA were 2932 mm diamafter 4 wk, with abundant conidiophores arranged inconcentric rings, brownish grey (ME34F3), flat,slightly granulose; reverse brownish grey(M4E34F3); a diffusible pigment brownish orange tobrown (M6C66E8). On PCA, colonies 2025 mmdiam after 4 wk, olive-grey (M3E23F2), with whitishmargins, flat, velvety; reverse olive-grey. On PDA,3035 mm diam after 4 wk, pale yellow to greyishyellow (M1A31B4), olive (M1E41F4) at the centre,slightly fasciculate, irregularly folded; reverse orangegreyto greyish orange (M5B25B3). At 15 ºC colonygrowth rates on OA and PDA were similar to those at25 ºC, while on PCA they were restrictedly (1216mm in 4 wk), sporulation was scarce and the diffusiblepigment was absent in all media assayed. No growthwas observed at 37 ºC.Figs 2331. Oidiodendron reticulatum (IMI 391999). 2325. Two different type of conidiophores, simple on the left and withan apical reticulate network of hyphae on the right. 2628. Network wall ornamentation. 29, 30. Fertile hyphae producingarthroconidia. 31. Arthroconidia. Scale bars: 23, 25 = 50 m, 24 = 30 m, 2628, 30 =10 m, 29 = 20 m, 31 = 2 m.165

CALDUCH ET AL.Figs 3235. Oidiodendron reticulatum (IMI 391999). 32.Habit sketch. 33. Conidiophore. 34. Fertile hyphae borninglaterally from a hyphae of the reticulum. 35. Arthroconidia.Scale bars: 32 = 50 m, 33 = 25 m, 34 = 5 m, 35 = 2 m.Specimen examined: Spain, Canary Islands, Gran CanariaIsland, from soil sample, 7 Mar. 1997, coll. B. Acosta &A.M. Stchigel, holotype IMI 391999; ex-type culture CBS113933 = FMR 6766.Notes: Oidiodendron hughesii and O. myxotrichoidesare the species showing a dematiaceous, branched andanastomosed reticulum of hyphae similar to thatpresent in the conidiophore upper part of O. reticulatum.However, in O. myxotrichoides the reticulatestructure is never borne terminally on an erect stipitateconidiophore, as happens in O. hughesii and O. reticulatum.Moreover, conidia of O. myxotrichoides arepredominantly globose or subglobose and smooth orfinely rugose under SEM, while those of O. reticulatumare ellipsoidal, with roughened or echinulatewalls. Oidiodendron hughesii differs from O. reticulatummainly in the ornamentation of the hyphae of thereticulum, which are asperate and smooth-walleddistally, conidia being hyaline and rather thick-walled.Additionally, O. hughesii is psychrophilic, growingbetter at 15 ºC than at 25 ºC, in contrast to O. reticulatum,which is mesophilic.PhylogenyThe amplicons from the three Oidiodendron strainswere consistent with those of other Oidiodendronspecies and their relatives studied by Hambleton et al.(1998). The majority rule consensus tree, resultingfrom 1000 bootstrap replications of maximum parsimonyanalysis of the Oidiodendron species and relatedtaxa data set, using the heuristic search algorithm.The topology of the phylogenetic tree supports theproposal of the three new species. All Oidiodendron,Myxotrichum and Byssoascus strains included in thestudy fall into a monophyletic clade supported by abootstrap value of 79 %. These results agree withHambleton et al. (1998), who demonstrated that thethree genera conformed a well-supported monophyleticgroup within the Myxotrichaceae, and thatthis group diverged considerably from other membersof the family, i.e. Gymnostellatospora japonica andPseudogymnoascus roseus. In our study, the ingroupwas split into many subclades, some of them unispecific,e.g. that formed by the O. myxotrichoides strain, aspecies recently described by Calduch et al. (2002)which develops a structure similar to those present atthe upper part of the conidiophore of O. hughesii(Udagawa & Uchiyama 1998) and of the new speciesO. reticulatum. Unfortunately, O. hughesii could notbe included in this molecular study because ex-typecultures are not available. Oidiodendron reticulatumwas placed in a clade together with O. griseum, O.flavum and M. arcticum, which was supported by amoderate bootstrap value (78 %). However, none ofthese species develop the typical complex conidiophoresof O. reticulatum. The four members of thisclade develop simple conidiophores, but the otherthree species can be easily distinguished from O.reticulatum by some morphological features of theirconidiophores and conidia. The conidiophores of O.flavum are shorter (maximum up to 100 m long) andthe conidia larger (3.56 2.53.5 m) (Ellis 1976).The conidia of O. griseum and those of the anamorphof M. arcticum are pale greyish green and nearlysmooth (Ellis 1971, Udagawa et al. 1994). The othertwo new species, O. muniellense and O. ramosum,were grouped with O. setiferum and O. tenuissimum ina separate clade supported by a low bootstrap value(56 %). Oidiodendron tenuissimum differs from theother species included in the clade because it onlydevelops the unbranched stipitate conidiophorestypical of the genus (Ellis 1971, 1976). As expected,O. ramosum and O. setiferum, two species with somesimilar features, clustered close each other, but with alow bootstrap support, which confirms that they aretwo different species.166

NEW SPECIES OF OIDIODENDRONFig. 36. Parsimony heuristic phylogram obtained for 5.8S and internal transcribed spacer (ITS2) regions of the species listed inTable 1. Bootstrap probabilities (1000 replicates) are indicated on the nodes. The tree statistics for the analysis are as follows:tree length = 252 steps; consistency index = 0.5357; retention index = 0.4730, rescaled consistency index = 0.2534 and homoplasyindex = 0.4643.Key to Oidiodendron species1. Presence of globose or subglobose, dark brown sporodochia..................................................O. myxotrichoides1. Sporodochia absent...........................................................................................................................................22. Teleomorph present ..........................................................................................................................................32. Teleomorph absent ...........................................................................................................................................43. Ascomata with a dark reticulate peridium; ascospores ellipsoidal or fusiform,longitudinally striate, hyaline to pale yellow ......................... Oidiodendron anamorphs of Myxotrichum spp.*3. Ascomata with a white, cottony peridium; ascospores fusiform, striate,greenish yellow ..............................................................Oidiodendron anamorph of Byssoascus striatosporus4. Conidiophores with dematiaceous seta-like branches in the upper part ..............................................................54. Conidiophores otherwise ..................................................................................................................................9167

CALDUCH ET AL.5. Branches anastomosing to form a more or less globose, reticulate network, with the conidial mass in the centre;simple conidiophores produced simultaneously.................................................................................................65. Branches otherwise; simple conidiophores absent .............................................................................................76. Psychrophilic; branches basally asperate, smooth towards the apex; conidia hyaline ........................ O. hughesii6. Mesophilic; branches coarsely verrucose and spinulose along their length; conidia pale brownto olivaceous-brown ....................................................................................................................O. reticulatum7. Upper part of the conidiophores with dematiaceous sterile branches................................................ O. setiferum7. Upper part of the conidiophores with dematiaceous fertile branches..................................................................88. Branches long (up to 130 m), verruculose to verrucose, broadly recurved; conidia subgloboseto ellipsoidal, slightly roughened under SEM, 1.53 12 m....................................................... O. ramosum8. Branches shorter (up to 60 m), smooth and becoming slightly roughened distally, straight; conidia globose tosubglobose, echinulate under SEM, 1.52.5 m diam .................................................................O. muniellense9. Conidiophores 250870 m long; conidia cylindrical, with truncate ends, 511 2.53.5 m........O. robustum9. Conidiophores shorter; conidia not combining the above characteristics..........................................................1010. Conidia lens-shaped, with a thick-walled ring, 35.5 23 m; colonies violaceous to purple-black .O. cerealis10. Conidia and colonies otherwise.......................................................................................................................1111. Pigmented chlamydospores present in culture .................................................................................................1211. Pigmented chlamydospores absent..................................................................................................................1412. Chlamydospores 4.514 3.512.5 m; conidia 415 313 m, usually ellipsoidal orcylindrical, sometimes two-celled.....................................................................................................O. terrestre12. Chlamydospores and conidia otherwise...........................................................................................................1313. Chlamydospores 49 m diam; conidia fusiform or doliiform, 26 1.22 m............... O. chlamydosporicum13. Chlamydospores 35 2.53 m; conidia cylindrical, guttuliform or ellipsoidal, 24 12 m...O. scytaloides14. Colonies yellowish .........................................................................................................................................1514. Colonies coloured otherwise...........................................................................................................................1715. Conidiophores up to 300 m long; conidial chains often undulate; conidia 24 1.53 m............. O. citrinum15. Conidiophores shorter.....................................................................................................................................1616. Conidiophores up to 100 m long; conidial chains straight; conidia 3.56 2.53.5 m.....................O. flavum16. Conidiophores rather short or absent; conidial chains curved; conidia 3.85 2.53.3 m..........O. sulphureum17. Conidia doliiform or cylindrical, truncate at the ends ......................................................................................1817. Conidia otherwise...........................................................................................................................................1918. Conidia olivaceous-brown, often bearing darkened frills terminally, 36.5 1.53 m................. O. truncatum18. Conidia hyaline, with inconspicuous frills, 33.5 1.52 m ............................................................ O. pilicola19. Conidia mostly globose to subglobose, thick-walled .......................................................................................2019. Conidia variable in shape, mostly thin-walled .................................................................................................2120. Conidia with alternating dark and light brown bands in the wall, 2.55 m diam;colonies isabelline to greyish sepia............................................................................................O. periconioides20. Conidia distinctly echinulate with dark spines, pale to mid brown, 2.54 m diam;colonies olivaceous or purplish black.........................................................................................O. echinulatum168

NEW SPECIES OF OIDIODENDRON21. Colonies with a red pigment diffusing into the agar; conidia ellipsoidal or subspherical,24 1.52 m ........................................................................................................................O. rhodogenum21. Colonies without a red pigment diffusing into the agar....................................................................................2222. Colonies pale grey or off-white; conidia subglobose or short cylindrical, 2.54 22.5 m,pale olive, often forming curled chains ................................................................................................ O. maius22. Colonies grey to olivaceous brown; conidia otherwise ....................................................................................2323. Conidia smooth or minutely verruculose, paler, oblong or ellipsoidal..............................................................2423. Conidia distinctly verruculose, brown, globose, subglobose or ellipsoidal, 24 1.52.5 m.....O. tenuissimum24. Conidia hyaline, 1.52.5 1.3.7 m................................................................................................. O. gracile24. Conidia pale greyish green, 23.5 1.52 m .................................................................................. O. griseum*The morphological differences among the Oidiodendron anamorphs of Myxotrichum spp. are difficult to establish. They arealways associated with the corresponding teleomorphs. These species are differentiated from each other by the morphology oftheir ascomata.ACKNOWLEDGEMENTSThe authors are grateful to E. Descals (IMEDEA, CSIC-UIB, Esporles, Mallorca, Spain) for his comments, to theConsejería de Agricultura of the Principado de Asturias,Spain, for the permission to collect the samples used in thisstudy, and to M. 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