Some stromatic pyrenomycetous fungi from northernThailand - 1. Biscogniuxia, Camilleaand Hypoxylon (Xylariaceae)

L. N. Vasilyeva & S. L. Stephenson & K. D. Hyde &

A. H. Bahkali

Received: 27 September 2011 /Accepted: 18 December 2011 /Published online: 5 January 2012# The Mushroom Research Foundation 2012

Abstract Fourteen species of stromatic pyrenomycetousfungi (family Xylariaceae) collected in northern Thailandare discussed. Six of these (Biscogniauxia lithocarpi,Camillea malaysiensis var. macrospora, Hypoxylon juven-tuterubrum, H. pseudoretpela, H. rubroargillaceum, and H.sepipigmentum) are described as taxa new to science. Illus-trations of these taxa are provided, and they are comparedwith similar taxa known from the Western Hemisphere.

Keywords Ascomycota . SE Asia . Taxonomy. Xylariales

Introduction

Stromatic members of the family Xylariaceae in Thailandare very diverse and have been collected extensively,

especially during the past decade. They have been the focusof several Ph.D. dissertations and the subject of posterpresentations at a number of different Asian meetings(Thienhirun and Whalley 1998; Suwannasai et al. 2004,2006; Phosri et al. 2008; Osono et al. 2009; Srikitikulchai2009; Seehanan & Petcharat 2011). However, publicationsproviding descriptions and illustrations of the representa-tives of this group of fungi found in Thailand are few(Whalley et al. 1995, 1998; Sihanonth et al. 1998; Suwannasaiet al. 2005; Bangyeekhun 2008; Fournier et al. 2010). Thereare some lists of species reported from Thailand (Schumacher1982; Okane et al. 2008), but these are not helpful in identi-fication and thus are not very reliable for the assessment ofactual species biodiversity of stromatic xylariaceous fungi inthis country. Herein we provide information on 14 speciescollected in northern Thailand.

Methods

The specimens considered herein were collected in twoprovinces in northern Thailand—Chiang Mai (Mae TaengDistrict near the villages of Pha Deng and Mae Sae; the DoiSuthep temple in the vicinity of the city of Chiang Mai) andChiang Rai (Doi Pui Mountain in the Muang District; in thevicinity of Mae Fah Luang University). All specimens wereobtained during the second half of June, which does notappear to be the best time for collecting xylariaceous fungi.Many specimens were too young or too old, so that it wasdifficult to observe asci and ascospores in good condition.Microscopic analyses were carried out using standard tech-niques. Material was mounted in 10% KOH for examinationof stromatal pigments and dehiscence of the perispore,whereas Melzer’s iodine reagent for used for examinationof the ascal apical ring. The color designation follows

L. N. Vasilyeva (*)Institute of Biology and Soil Science,Far East Branch of the Russian Academy of Sciences,Vladivostok 690022, Russiae-mail: vasilyeva@biosoil.ru

S. L. StephensonUniversity of Arkansas,Fayetteville, AR 72701, USA

K. D. HydeInstitute of Excellence in Fungal Research,Mae Fah Lung University,Chiang Rai 57100, Thailand

K. D. HydeSchool of Science, Mae Fah Lung University,Chiang Rai 57100, Thailand

K. D. Hyde :A. H. BahkaliBotany and Microbiology Department, College of Science,King Saud University,Riyadh 11442, Saudi Arabia

Fungal Diversity (2012) 55:65–76DOI 10.1007/s13225-011-0150-9

Rayner (1970). Photographs of stromata and associatedstructures were taken using a Nikon D40x digital camera.The material from Thailand is deposited in the herbarium ofMae Fah Luang University (MFLU). Some specimens col-lected in the southern United States and deposited in theherbarium of the Institute of Biology and Soil Science(VLA) were used for the purpose of morphologicalcomparisons.

Taxonomy

Biscogniauxia capnodes (Berk.) Y.M. Ju & J.D. Rogers var.limoniispora Y.M. Ju & J.D. Rogers, Mycotaxon 66: 26,1998. (Fig. 1)

Description: Ju et al. 1998.Material examined: Thailand, Chiang Mai Province, Mae

Taeng District, Pha Deng village, Mushroom Research Centre,19 June 2011, L. Vasilyeva (MFLU11–1150).

Commentary: This taxon was described originally fromthe Nakhon Nayok Province in central Thailand (Ju et al.1998) and has not yet been found in any other country.

The typical variety of Biscogniauxia capnodes and alsoB. capnodes var. microspora (not validly published) areknown from Thailand (Thienhirun et al. 2003; Tang et al.2007). In addition, B. nummularia (Bull.: Fr.) Kuntze var.exutans (Cooke) Van der Gucht, B. nummularia var. merril-lii (Bres.) Van der Gucht (Okane et al. 2008) and B. num-mularia var. pseudopachyloma (Speg.) Whalley (Whalley etal. 1995) have been reported, but the two last names areconsidered to be synonyms of B. capnodes var. capnodes

(Ju et al. 1998). As for B. capnodes var. exutans, this namewas supposed to be a synonym of B. fuscella (Rehm) SanMartín & J.D. Rogers, which is currently known only fromthe state of Tamaulipas in Mexico, which is located on thecoast of the Gulf of Mexico, and the neighboring state ofTexas in the United States. It seems unlikely that a speciesassociated with the ‘Caribbean center’ of diversity for stro-matic pyrenomycetous fungi would occur in Thailand. Bis-cogniauxia mediterranea (De Not.) Kuntze var. microspora(J.H. Mill.) Y.M. Ju & J.D. Rogers, although reported fromThailand (Okane et al. 2008), does not seem likely to occurhere either. This taxon is known only from North America(Ju et al. 1998) and temperate latitudes of eastern Russia(Vasilyeva & Stephenson 2010).

Biscogniauxia lithocarpiLar.N.Vassiljeva, S.L. Stephenson& K.D. Hyde, sp. nov. (Fig. 3b)

MycoBank: MB563404Stromata applanata, ambitu irregularia, superficiem brun-

neam praedita, proxime infra superficie et inter peritheciiscarbonacea. Perithecia elongata, 300–400 μm alta, 150–200 μm lata; ostiola superficie aequaltum vel inferia, punctataet substantia ochracea impleta. Asci cylinracei, partibus spor-iferis 130–140×15–16 μm, stipitibus 25–30 μm longitudine,annulo apicali in liquore iodato Melzeri cyanescente, discoi-deo, circa 2 μm alto, 7–8 μm lato. Ascosporae atro-fuscae,unicellulares, ellipsoideae vel subglobosae, leves, (13–)15–17(–17.5)×12–14 μm, rima germinativa longa recta praeditae.

Stromata applanate, irregular in outline, surface brown,carbonaceous immediately beneath the surface and betweenperithecia. Perithecia elongated, 300–400 μm high, 150–200 μm wide, ostioles at the same level or lower than the

Figs. 1-2 Stromata: 1.Biscogniauxia capnodes var.limoniispora. 2. B.uniapiculata. Scalebar01.7 mm

66 Fungal Diversity (2012) 55:65–76

stromatal surface, with openings punctate and overlain withan ochreous substance. Asci cylindrical, 130–140×15–16 μm in the spore-bearing part, stipes 25–30 μm, with anapical ring bluing in Melzer’s iodine reagent, discoid, about2 μm high, 7–8 μm wide. Ascospores dark brown, unicel-lular, ellipsoid to subglobose, with broadly rounded ends,smooth, (13–) 15–17(–17.5)×12–14 μm, with a straightgerm slit that extends the length of the spore.

Etymology: refers to the genus (Lithocarpus) of the hostplant.

Material examined: Thailand, Chiang Mai Province, MaeTaeng District, Pha Deng village, Mushroom Research Centre,on dead branch of Lithocarpus sp., 22 June 2011, L. Vasilyeva(Holotype: MFLU11–1151).

Commentary: This species is strikingly similar to Biscog-niauxia schweinitzii Y.M. Ju & J.D. Rogers in having sub-globose ascospores, but it differs in their size as well as inthe size of the asci and apical rings as given by Ju et al.(1998). However, the size of the ascospores corresponds tothe measurements given in the description provided byMiller (1961), and the difference lies mostly in the stromataof two species (Fig. 3a–b). We have collected B. schweinitziiin Arkansas, and one stroma from a typical specimen isshown here for comparison. The stromata of B. lithocarpiare lighter, smoother and irregular in shape.

Biscogniauxia schweinitzii was reported from SoutheastAsia (Papua New Guinea) by Van der Gucht (1992) as B.macula (Schwein.) Van der Gucht, and the material she exam-ined was said to correspond completely with the descriptiongiven by Miller (1961) and also to be in total agreement withthe type collection. However, we believe that typicalB. schwei-nitzii is currently known only from the southeastern UnitedStates (Florida, Georgia, North Carolina and South Carolina)and thus has a very limited geographical distribution. To ourknowledge, this species has never been reported from any-where in the tropics. As such, we suspect that the material fromPapua New Guinea could represent B. lithocarpi.

Biscogniauxia uniapiculata (Penz. & Sacc.) Whalley &Læssøe in Whalley, Læssøe & Kile, Mycol. Res. 94: 239,1990. (Fig. 2)

Description: Ju et al. 1998.Material examined: Thailand, Chiang Mai Province, Mae

Taeng District, Pha Deng village, Mushroom Research Centreon dead branches of Macaranga (?), 22 June 2011, L.Vasilyeva (MFLU11–1152).

Commentary: This species was already known fromThailand (Nungent et al. 2005). It was described from Java,and the majority of specimens examined by Ju et al. (1998)were from such places as Malaysia, Indonesia, and thePhilippines.

Fig. 3 Stromata: aBiscogniauxia schweinitziifrom Arkansas (BuffaloNational River Park: VLAP-2399). b B. lithocarpi. Scalebars: A–B00.9 mm

Fungal Diversity (2012) 55:65–76 67

Camillea malaysiensis M.A. Whalley var. macrosporaLar.N. Vassiljeva, S.L. Stephenson & K.D. Hyde, var. nov.(Fig. 4b)

MycoBank: MB563305A varietate typica differt in ascosporis majoribus.Differs from typical variety in ascospores 15–18×5.5–

6.5 μm.Material examined: Thailand, Chiang Rai Prov., Muang

District, T. Thasai, dead branch of unidentified tree, 30 June2011, L. Vasilyeva (MFLU11–1153).

Commentary: The very similar species, Camillea tinctor,had been reported previously from Thailand (Thienhirun andWhalley 1998; Phosri et al. 2008), Singapore (Læssøe et al.1989) and Papua New Guinea (Van der Gucht 1992), but thespecimens from different localities in Southeast Asia shouldbe subjected to a detailed comparative study to determine ifthey do represent C. tinctor. When the known distribution ofthis species in the United States and the Caribbean basin(Cuba, French Guiana, Nicaragua, Puerto Rico and St. Croix:Miller 1961) is taken into account, one might reasonablyexpect that a separate taxon occurs in Southeast Asia.

Camillea malayasianensis was described from materialcollected in Malaysia and was indicated as differing from C.tinctor in the considerably smaller ascospores, no evidenceof the yellow staining of the wood immediately beneath thestroma, and the papillate (versus inconspicuous and slightlypunctiform) ostioles (Whalley et al. 1999). Our specimenalso shows no evidence of yellow staining of the woodbeneath the stroma and has papillate ostioles as is the casefor C. malayasianensis. However, the size of the ascospores

(15–18 μm long) corresponds to that of C. tinctor, whereasthose of C. malayasianensis are described as only 8.8–15 μm long. Both species seem to have papillate ostioles,and Miller (1961) described ‘small papillate ostioles’ for C.tinctor, although the surface of stromata in the specimenfrom Thailand appear to be rougher because of more prom-inent ostioles (Fig. 4b) in comparison with material from thesoutheastern United States (Fig. 4a). The color of the stro-mata—brown in the material from North America andshiny-black in our specimen from Thailand—is also differ-ent. The size of the ascospores does not allow us definitelyto assign this specimen to Camillea malayasianensis, so thenew variety is suggested.

Hypoxylon anthochroum Berk. & Broome, J. Linn. Soc.Bot. 14 : 122, 1873. (Fig. 5)

Material examined: Thailand, Chiang Rai Province,Muang District, Doi Pui Mountain, on bark of unidentifiedtree, 30 June 2011, L. Vasilyeva (MFLU11–1153).

Commentary: This species was already known fromThailand (Suwannasai et al. 2005; Phosri et al. 2008), andthe lectotype is indicated as being from Sri Lanka (Ju &Rogers 1996). It seems to have a very wide distribution inthe tropics and subtropics. This is the only specimen ofHypoxylon in our material from Thailand that has the sameappearance as specimens of H. anthochroum from NorthAmerica, collected in the Great Smoky Mountains NationalPark (North Carolina) and the Big Thicket National Preserve(Texas) (VLA P–1611 and P–2460).

Hypoxylon fulvoochraceum Rehm, Philipp. J. Sci. 8 :188, 1913. (Fig. 7)

Fig. 4 Stromata: a Camilleatinctor from Maryland (LaurelPark: VLA P-1457). b Camilleamalayasianensis var.macrospora. Scale bars:A02.5 mm, B01.5 mm

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Stromata consisting of prominent and confluent, some-times cupulate, brownish perithecia, united by a thin stro-matal layer below that looks like a wide and dark brownmargin around the perithecial aggregations; KOH-extractable pigments ochreous, brick or orange. Peritheciaspherical, 150–180 μm diam. Asci not seen. Ascosporesbrown to dark brown, unicellular, ellipsoid-inequilateral,with narrowly rounded ends, 12–15 (–16)×5–6.5 μm, with

germ slit slightly shorter than spore length; perispore inde-hiscent in 10% KOH.

Material examined: Thailand, Chiang Rai Province,Muang District, Doi Pui Mountain, on bamboo culms, 30June 2011, L. Vasilyeva (MFLU11–1154).

Commentary: The name of this species is listed as asynonym of H. lenormandii Berk. & M.A. Curtis, the holo-type of which was from Cuba (Ju & Rogers 1996).

Figs. 5-6 Stromata: 5.Hypoxylon anthochroum. 6. H.lienhwaheense. Scalebar02 mm

Figs. 7-8 Stromata: 7.Hypoxylon fulvoochraceum. 8.Hypoxylon pseudoretpela.Scale bar00.9 mm

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Hypoxylon fulvoochraceum was described from bambooculms in the Philippines (Rehm 1913) and also found inThailand (Kanchanaburi Province) on the same substrate (Ju& Rogers 1996). It is highly probable that the species onbamboo culms in Southeast Asia is a separate taxon.

The KOH-extractable pigments indicated for H. lenor-mandii are rather variable (hazel, sienna, cinnamon, fulvous,umber or ochreous), and this might be an indirect indicationthat there is a species complex represented by the name “H.lenormandii” in the literature. These pigments are ‘orange’or ‘rust’ in our material, but KOH-extractable pigmentsindicated as “orange, reddish, or rust“ include ”orange,luteous, ochreous, sienna, scarlet, fulvous, or rust” accord-ing to Ju & Rogers (1996, p. 67). As such, our material fallswithin the range of “H. lenormandii” with respect to thisfeature. The size of the ascospores in our material corre-sponds to that of H. lenormandii too, but the ascosporesdiffer in the nature of the perispore which is indehiscent in10% KOH.

Two species restricted to bamboo culms were describedrecently from Thailand (Suwannasai et al. 2005). These areH. kanchanapisekii Suwannasai, Rodtong, Thienhirun &Whalley and H. sublenormandii Suwannasai, Rodtong,Thienhirun & Whalley. Both species have smaller asco-spores (mostly up to 11.3 or 11.5 μm long against 12–15 μm long for H. lenormandii and H. fulvoochraceum)and are characterized by brown vinaceous or umber KOH-extractable pigments.

Hypoxylon rugulosporum Van der Gucht, Y.M. Ju & J.D.Rogers, described from bamboo culms in Papua NewGuinea (Van der Gucht et al. 1997), has ascospores 12–16×5–7.5 μm but differs in the dark livid KOH-extractable pigments.

Hypoxylon juventuterubrum Lar.N. Vassiljeva, S.L.Stephenson & K.D. Hyde, sp. nov. (Fig. 9b)

MycoBank: MB563306Stromata late effusa, ambitu irregularia, tumulis perithe-

ciorum inconspicuis vel leviter conspicuis, 0.5–1 mmcrassa, extreme juventute lateritio-rubra, aetate griseo-brunneola, sub superficie et inter perithecia granulis laeterubris conspersa, granulis luteis in KOH dissolutis. Perithe-cia globosa, 150–200 μm diam., ostiola umbilicata. Ascinon vidi. Ascosporae fuscae vel atro-fuscae, unicellulares,ellipsoideo-inequilaterales, 12–15×4.5–6.5 μm, rima germi-nativa recta longa praeditae; perisporium in 10% KOHindehiscens vel raro dehiscens.

Stromata widely effused, irregular, plane or with slightlyconspicuous perithecial mounds, 0.5–1 mm thick; surfacebrick-red at first, becoming grey-brownish; bright red gran-ules immediately beneath surface and between perithecia,with KOH-extractable pigments luteous. Perithecia spheri-cal, 150–200 μm diam., ostioles umbilicate. Asci not seen.Ascospores brown to dark-brown, unicellular, ellipsoid-

inequilateral, 12–15×4.5–6.5 μm, with straight germ slitspore length; perispore indehisent, or very infrequentlydehiscent, in 10% KOH.

Etymology: refers to the brick-red young stromata.Material examined: Thailand, Chiang Rai Province, vi-

cinity of the city of Chiang Rai, campus of Mae Fah LuongUniversity, on bark of an unidentified tree, 2 July 2011, L.Vasilyeva (Holotype: MFLU11–1155).

Commentary: Our material is not in very good condition,and portions of the stromata are either too young or too old(red and grey-brownish examples—Fig. 9b). The first ofthese contain only immature perithecia, whereas the latterdisplay only scanty ascospores. The stromata are somewhatsimilar to those in Hypoxylon crocopeplum Berk. & M.A.Curtis, which is also initiated as brightly colored patches,often covered by conigiogenous structures, but in H. croc-opeplum the young stromata are lemon-yellow (sometimeswith an orange tinge). Both species are characterized by thesame range in ascospore size, have similar colors of KOH-extractable pigments and possess stromatal granules withsimilar tinges of color, but typical stromata of H. crocope-plum (Fig. 9a) have a rather characteristic granular appear-ance because of the prominent perithecia. The same kind ofstromata can be seen in the photograph of H. crocopeplumfrom the Great Smoky Mountains National Park (Vasilyevaet al. 2007, Fig. 5, photo by A.N. Miller).

Hypoxylon crocopeplum has been reported from Thailand(Whalley et al. 1995; Okane et al. 2008; Phosri et al. 2008)and is supposed to be widely distributed in the tropics andsubtropics. However, the “typical form” of H. crocopeplumwith its fairly conspicuous perithecial mounds is observedmostly in eastern North America (Ju and Rogers 1996).Many other forms that have been collected seem to beatypical and might well belong to different species orvarieties.

Hypoxylon lienhwaheense Y.M. Ju & J.D. Rogers,Mycol. Memoir 20 : 143, 1996. (Fig. 6)

Description: Ju & Rogers 1996.Material examined: Thailand, Chiang Mai Province, vi-

cinity of the city of Chiang Mai, near the Doi Suthep temple,Huai Kok Ma, 21 June 2001, L. Vasilyeva (MFLU11–1156).

Commentary: This species was described from southernChina (Ju & Rogers 1996; Ma 2011) and has been reportedfrom Thailand (Thienhirun et al. 2003; Phosri et al. 2008).Among the species of Hypoxylon in which the stromata havevinaceous shades, H. lienhwaheense can be distinguished byits violet KOH-extractable pigments and relatively smallascospores (6–7.5 μm).

Hypoxylon pseudoretpela Lar.N. Vassiljeva, S.L.Stephenson & K.D. Hyde, sp. nov. (Fig. 8)

MycoBank: MB563307Stromata late effusa, ambitu irregularia, circa 0.5 mm

crassa, tumulis peritheciorum inconspicuis vel leviter

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conspicuis, externe castanea vel atro-fusca sed luce trans-eunte brunneo-vinosa, sub superficie et inter peritheciagranulis rubellis conspersa, granulis aurantiacis in KOHdissolutis. Perithecia globosa, 100–150 μm diam., ostiolaumbilicata. Asci partibus sporiferis 50–60×4–5 μm, stipiti-bus 25–37.5 μm longitudine, annulo apicali in liquoreiodato Melzeri cyanescente, discoideo, 1.5–2 μm lato. Asco-sporae fuscae, unicellulares, ellipsoideo-inequilaterales,7.5–9×3.5–4 μm, rima germinativa recta longa praeditae;perisporium in KOH indehiscens.

Stromata widely effused, irregular in shape, thin (up to0.5 mm thick), with inconspicuous to slightly conspicuousperithecial mounds, surface chestnut or dark brown but withvinaceous shades under direct light, reddish granules imme-diately beneath the surface and between perithecia, withorange KOH-extractable pigments. Perithecia spherical,100–150 μm diam., ostioles umbilicate. Asci 50–60×4–5 μm long in the spore-bearing portions, the stipes 25–37.5 μm long, with an apical ring bluing in Melzer’s iodinereagent, discoid, 1.5–2 μm broad. Ascospores brown, uni-cellular, ellipsoid, slightly inequilateral, 7.5–9×3.5–4 μm,with a straight germ slit extending almost the entire lengthof the spore, perispore indehiscent in 10% KOH.

Etymology: ‘pseudo’ 0 false; referring to the color of thestromatal surface and the KOH-extractable pigments that arealso found in H. retpela.

Material examined: Thailand, Chiang Mai Province, MaeTaeng District, Pha Deng village, Mushroom Research

Centre, dead branch of unidentified tree, 22 June 2011, L.Vasilyeva (Holotype: MFLU11–1157).

Commentary. There are only two other species of Hypo-xylon known to have a stromatal surface characterized byvinaceous shades and orange KOH-extractable pigments.These are H. fendleri Berk. and H. retpela Van der Gucht& Van der Veken. Hypoxylon retpela was described origi-nally from Papua New Guinea (Van der Gucht and Van derVeken 1992) and has been reported from Indonesia andsouthern China (Ju and Rogers 1996), as well as Thailand(Phosri et al. 2008). Although H. fendleri was also indicatedas occurring in Indonesia and southern China by Ju andRogers (1996), as well as in Thailand by Phosri et al.(2008), this species actually appears to have a distributioncentered around the Caribbean Sea and the Gulf ofMexico (the states of Campeche and Quintana Roo inMexico, the island of St. John and French Guiana), andthe holotype was collected in Venezuela (Ju and Rogers1996).

Both H. fendleri and H. retpela differ from H. pseudor-etpela in having larger ascospores (9–12 μm against 7.5–9 μm) and a perispore that is dehiscent in 10% KOH. It isalso noteworthy that the specimens of H. pseudoretpelacollected in Thailand uniformly displayed a strong dischargeof ascospores, so that the envelopes were always coveredwith a thick spore deposit on the inside.

Hypoxylon rubroargillaceum Lar.N. Vassiljeva, S.L.Stephenson & K.D. Hyde, sp. nov. (Figs. 10b-c)

Fig. 9 Stromata: a Hypoxyloncrocopeplum from Tennessee(Great Smoky MountainsNational Park: VLA P-1621). bH. juventuterubrum. Scale bars:A01.2 mm, B - 1.7 mm

Fungal Diversity (2012) 55:65–76 71

MycoBank: MB563308Stromata glomerata, tumulis peritheciorum valde conspi-

cuis, initio lateritio-rubra, dein argillacea, sub superficie etinter perithecia granulis laete coccineis conspersa, granulislaete luteis vel ochraceis in KOH dissolutis. Perithecia 300–400 μm diam., ostiola umbilicata. Asci partibus sporiferis70–90×10–12 μm, stipitibus 30–40 μm longitudine, annuloapicali in liquore iodato Melzeri non cyanescente. Asco-sporae fuscae, unicellulares, ellipsoideo-inequilaterales,11–15×6–7 μm, rima germinativa recta longa praeditae;perisporium in KOH dehiscens.

Stromata glomerate, with conspicuous perithecialmounds, at first brick red, later clay-colored, granules brightred immediately beneath the surface and between perithecia,with KOH-extractable pigments luteous to ochreus. Perithe-cia 300–400 μm diam., with whitish circles around umbil-icate ostioles. Asci 70–90×10–12 μm in the spore-bearingportions, stalks 30–40 μm long, with an apical ring lacking,ascal tip not bluing in Melzer’s iodine reagent. Ascosporesbrown to dark-brown, unicellular, ellipsoid-inequilateral,11–15×6–7 μm, with straight germ slit extending the lengthof the spore, perispore dehiscent in 10% KOH.

Etymology: refers to the red granules in a clay-coloredstromata.

Material examined: Thailand, Chiang Rai Province,Muang District, Doi Pui Mountain, on the dead branchesof a tree (Fabaceae?), 30 June 2001, L. Vasilyeva (Holotype:MFLU11–1158)

Commentary: This species is strikingly similar to H.flavoargillaceum J.H. Mill., which is known from two col-lections made in Colombia and Venezuela (Ju and Rogers1996). It has the ascospores of the same size, a germ slit thatextends the length of the spore, a perispore dehiscent in 10%KOH, glomerate stromata, similar KOH-extractable pig-ments, and even a clay-colored surface of the stromata,which is reflected in the Latin name ‘argillaceum’. Howev-er, ascal tips in H. rubroargillaceum do not exhibit a bluingreaction in Melzer’s iodine reagent and the granules imme-diately beneath the surface and between perithecia are notyellowish brown but bright-red. This bright color can beseen even from the surface (Fig. 10c), so the fungus fromThailand was named H. rubroargillaceum in contrast to H.flavoargillaceum. These two species could represent aninstance of a vicarious biogeographical pattern, with one

Fig. 10 Stromata: a Hypoxylonnotatum on Quercus sp. fromArkansas (Buffalo NationalRiver Park: VLA P-2400). b–cHypoxylon rubroargillaceum: bYoung. c Old. Scale bars:A01 mm, B00.5 mm,C00.4 mm

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replacing the other in the two respective regions of the world(i.e., the Caribbean center of biodiversity and the SoutheastAsia).

The stromata of H. rubroargillaceum are somewhat sim-ilar to the fungus illustrated as H. notatum Berk. & M.A.Curtis from northern Thailand (Phosri et al. 2008), and thesetwo species are also similar in having glomerate stromata,comparable ascospore size, a perispore dehiscent in 10%KOH, a germ slit that extends the length of the spore, and anascal apical ring that is highly reduced or lacking. Thetypical form of H. notatum seems to be restricted to Quercusspp. in the southeastern United States, but the species isindicated as being more widely distributed (Ju and Rogers1996). Hypoxylon notatum is described as having darkbrown granules beneath the stromatal surface and pureyellow KOH-extractable pigments with a greenish yellowtinge (Ju and Rogers 1996). We have already indicated thatour specimens of H. notatum from the southeastern UnitedStates have an orange (or rusty) KOH-extractable pigment(Vasilyeva and Stephenson 2010), as is also the case for thetype specimen of H. notatum deposited in the FarlowHerbarium (on Quercus sp., Ravenel’s Fungi Car. Exs. N 36).

Hypoxylon sepipigmentum Lar.N. Vassiljeva, S.L.Stephenson & K.D. Hyde, sp. nov. (Fig. 11)

MycoBank: MB563309Stromata prostrata, plana et tenuia, irregulariter maculi-

formia, tumulis peritheciorum inconspicuis, externe pallide-

vel atro-vinosa, sub superficie et inter perithecia granulisgriseolis vel pallide-sepiaceis conspersa, granulis pallide-sepiaceis in KOH dissolutis. Perithecia globosa, 100–120 μm diam., ostiola umbilicata. Asci non-vidi. Asco-sporae fuscae vel atro-fuscae, unicellulares, valde inequila-terales, 10–12.5×5–6.5 μm, rima germinativa recta longapraeditae; perisporium in KOH dehiscens.

Stromata effused, plane and thin, occurring mostly assmall and irregular patches, with inconspicuous perithecialmounds, surface pale to dark vinaceous, granules grayish orpale-sepiaceus immediately beneath surface and betweenperithecia, with KOH-extractable pigments very pale sepia-ceus. Perithecia spherical, 100–120 μm diam., ostioles um-bilicate. Asci not seen. Ascospores brown to dark brown,unicellular, strongly inequilateral, sometimes with one sidealmost flat and another convex, 10–12.5×5–6.5 μm, with agerm slit that extends almost the length of the spore on theconvex side, perispore dehiscent in 10% KOH.

Etymology: refers to pale-sepiaceus KOH-extractablestromatal pigment.

Material examined: Thailand, Chiang Rai Province,Muang District, Doi Pui Mountain, on the bark of an un-identified tree, 30 June 2001, L. Vasilyeva (Holotype:MFLU11–1159)

Commentary: The shape of the ascospores in H. sepipig-mentum is similar to that of H. fuhreri G.J.D. Smith, K.D.Hyde & Whalley (Smith et al. 1999, Figs. 7–8), which was

Figs. 11-12 Stromata: 11.Hypoxylon sepipigmentum. 12.Hypoxylon trugodes. Scalebars: 1101 mm, 1201.4 mm

Fungal Diversity (2012) 55:65–76 73

described originally from Australia. In addition, the size ofthe ascospores is rather comparable in these two species,and a sepia color is mentioned in the list of KOH-extractablepigments (the others listed are umber and pale fulvous).However, the stromata of H. fuhreri are olivaceous and haveorange red granules present.

In having pale sepia KOH-extractable pigments andsmall patch-like and irregular stromata (cf. Miller 1961,Fig. 19), H. sepipigmentum is similar to Hypoxylon die-ckmannii Theiss. but has larger ascospores and perisporedehiscent in 10% KOH. H. dieckmannii was reported fromBrazil, French Guiana, Mexico and Louisiana (Ju andRogers 1996).

Hyloxylon subgilvum Berk. & Broome, J. Linn. Soc.Bot. 14 : 120, 1873. (Fig. 13)

Material examined: Thailand, Chiang Rai Province, campusof Mae Fah Luang University, on wood from unidentified tree,2 July 2011, L. Vasilyeva (MFLU11–1160)

Commentary: This species had been reported previouslyform Thailand (Whalley et al. 1995; Phosri et al. 2008). Ourspecimen has somewhat larger ascospores (10–13 μm long)than mentioned in the most recent description of the species(Ju and Rogers 1996: 7–11 μm long), but that larger range inspore size corresponds to what is given in the originaldescription (cf. Saccardo 1882). With respect to the sizerange in ascospores, our specimen is more similar to H.subcrocopeplum Y.M. Ju & J.D. Rogers, which is knownfrom New Zealand. The latter has similar stromata butdiffers in having a perispore that is indehiscent in 10%KOH. Hypoxylon subgilvum was described from Sri Lanka

and later found in Indonesia and southern China (Ju &Rogers 1996, Ma 2011), which are located in the samegeneral region of the world.

Hypoxylon trugodes Berk. & Broome, J. Linn. Soc. Bot.,14 : 122, 1873. (Fig. 12)

Description: Ju & Rogers 1996.Material examined: Thailand, Chiang Mai Province, Mae

Taeng District, Pha Deng village, Mushroom Research Centre,20 June 2011, L. Vasilyeva (MFLU11–1161)

Commentary: A number of species that have effusedstromata with a vinaceous color on the surface shareKOH-extractable pigments with yellowish tones, but all ofthem differ in one or more respects from H. trugodes. Thus,H. hypomiltum Mont. has smaller ascospores (6.5–9 μmlong), whereas in both H. chathamense Y.M. Ju & J.D.Rogers (13–15 μm long) and H. subcorticium Y.M. Ju &J.D. Rogers (13–18 μm long) the ascospores are larger. Thelatter is also characterized by having a perispore that isindehiscent in 10% KOH. The same ascospore length andindehisent perispore are characteristics of H. venezuelenseY.M. Ju & J.D. Rogers, which is found on bamboo culmsand is similar to H. pilgerianum Henn. in this respect.Recently, H. vinosopulvinatum Y.M. Ju, J.D. Rogers &Hsieh, which has a brown vinaceous surface of the stromataand amber to luteous KOH-extractable pigments (luteous inLatin is intensively yellow), was described (Ju et al. 2004),but this species differs in the shape of the stromata.

Hypoxylon trugodes is known primarily from SoutheastAsia, and there are records from Singapore, Sri Lanka, andsouthern China (Ju and Rogers 1996, Ma 2011). A fungus

Figs. 13-14 Stromata: 13.Hypoxylon subgilvum. 14.Hypoxylon vandervekenii. Scalebars: 1302 mm, 1401 mm

74 Fungal Diversity (2012) 55:65–76

identified as Hypoxylon cf. trugodes was reported fromNamtok Samlan National Park in Thailand by Okane et al.(2008).

Hypoxylon vandervekenii Van der Gucht, Y.M. Ju & J.D.Rogers, Mycologia 89: 506, 1997. (Fig. 14)

Description: Van der Gucht et al. 1997.Material examined: Thailand, Chiang Mai Province, Mae

Taeng district, Mae Sae village, on the bark of an unidentifiedtree, 23 June 2011, L. Vasilyeva (MFLU11–1162).

Commentary: This species was previously known onlyfrom Papua New Guinea. The major distinguishing featuresare an olivaceous stromatal surface and purplish KOH-extractable pigments.

Discussion

As indicated in the commentaries provided for particularspecies, the pan-tropical distribution of many species isexaggerated. In parallel to the biogeographical pattern ob-served in temperate latitudes and known as the ‘Grayandisjunction’ (Vasilyeva and Stephenson 2010), two tropicalcenters of biodiversity can be identified, and these tend to beinhabited by pairs of very similar, but separate, species ofpyrenomycetous fungi that replace one another when thetwo centers are compared. In the Western Hemisphere, thecenter of biodiversity is the region in and around the CaribbeanSea and the Gulf of Mexico, whereas in the Eastern Hemi-sphere, the corresponding center of biodiversity occurs inSoutheast Asia. The latter region encompasses (tentatively,based on currently available data) the Indochina Peninsular(Cambodia, Laos, Myanmar, Thailand and Vietnam) as well asthe southern provinces of China along with the countries of theMalay Archipelago (Indonesia, Malaysia and the Philippines)and Papua New Guinea.

The Southeast Asian center of biodiversity—along withseveral other centers elsewhere in the world—was alreadyrecognized by the Russian geneticist Vavilov (1926, 1935),and he referred to it as ‘Indo-Malayan’. He also found thatplants characterized by different combinations of the samefeatures are scattered over the globe and spent considerabletime searching for rare combinations predicted by him andthen found to occur in nature. All of these plant forms weredistributed in a manner similar to what would be expected ifsingle larger entity was broken and the fragments movedaway from each other in all directions.

The area in Southeast Asia outlined by Vavilov as theIndo-Malayan center of biodiversity is somewhat smallerthan would be inferred from considering all known recordsof xylariaceous fungi in this region. It does not include thesouthern provinces of China and Papua New Guinea, but wefound some species in northern Thailand that are alsoknown from Papua New Guinea. Two examples are

Hypoxylon vandervekenii and the species of Biscogniauxiadescribed herein as B. lithocarpi. The latter probably repre-sents the same taxon found in Papua New Guinea but treatedthere as B. schweinitzii (see above). In addition, H. retpela,described from Papua New Guinea, was also reported fromsouthern China by Ma (2011). Therefore, we think thatPapua New Guinea should be included in the concept ofthe Indo-Malayan center. Also, the southern provinces ofChina should be taken into consideration, since there arespecies known from Thailand (e.g., Hypoxylon lienhwa-cheense) that were described from that northern part of thecenter.

It might seem that the material considered in the presentpaper is too limited to make definite conclusions relating toseparate centers of diversity in the Caribbean Basin andSoutheast Asia, but this is anticipated to be the first in aseries of papers, and herein we present only a portion of ourown data and observations obtained in both areas and alsosupported by records reported by other mycologists.

Acknowledgements The research reported herein was funded in partby a grant (OISE-1042602) from the National Science Foundation tothe University of Arkansas. The support provided by the GlobalResearch Network for Fungal Biology and King Saud University isalso gratefully acknowledged.

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