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Home , Stereum, Stereum hirsutum, Tremella

Mycologia, 86(l), 199a, pp. 49-56. @ 1994, by The New York Botanical Garden, Bronx, IIY 10458-5126

Mycoparasitism of some speciesl

Walter Zugmaier are often present. Each tremelloid haustorial cell is Robert Bauer subtended by a clamp and consists of a subglobose Franz Oberwinkler basal part with one or more threadJike haustoriat fil- Unitersität Tübingen, Instüut rt;r Biologie L Lehrstuhl, aments that occasionally become attached to host cells, Spuielle Botanih und, Myhologie, Altf dcr Morgeßtelle Such tremelloid haustorial cells have been described 1, D-72076 Tübingen, Germanl from a variety of tremelloid fungi (Olive, 1946; Ban- doni, 196r, 1984, 1985, 1987; Bezerra and Kimbrough, 1978; Oberwinkler and Bandoni, r98r, 1983; Metzler Abstract: 'fhe parasitic interaction of Trernella mes- et al., 1989) and from species with affinities to the enterica, T. eruephala ar.d T. mlcophaga was studied by senszr Bandoni (1984) including Szygospora Iight and electron microscopy. The host range of T. alüa G. W. Martin (Oberwinkler and L owy , t98) , Chris- mesenterica was tested. with laeta, Peniophora tioßenia pallida f{auerslev (Oberwinkler and Bandoni, incernata, Phlebia rad,iata, Schizopora parad,oxa, Stereutn r98z; Oberwinkler et al., 1984), Filobasid.ium hirsutum and. stigma. It was demonstrated that floriforme L. Olive (Olive, 1968) and Filobasid,iella neoformans T. mesenterica is, at least in vivo, a mycoparasite the of Kwon-Chung (Kwon-Chung, r976). corticiaceous homobasidiomycele Peniophora laata. The ultrastructure ofthe host,parasite interface has Specialized interactive cells of f. nLesenterica, T. en- only been studied in three specie§. Bezerra and Kim- cephala and T. nycophaga, designated as tremelloid brough (r978) noted that tremelloid haustorial cells of haustorial cells with haustorial filaments, penetrated Tremella rh)tidh)sterii Bezerra & Kimbr. do not actually the cell walls of their respective hosts. A single micro- penetrate the cell wall of RlLytid.hysteriutrl rufulum pore connected the cytoplasm of the haustorial fila- (Spreng.) Speg. No ultrastructural differenriation was ment with that of the host cell. The pore membrane observed. A single micropore with direct cytoplasm- appears to be continuous with the plasmalemma of cytoplasm connection is present, however, between both cells. In older interaction structures, the micro- the haustorial filament of Tetragoniomlces uliginosus pore was often overgrown on the host side by sec- (I(arst.) Oberw. & Bandoni and the host cell of Rhi- ondary wall formation. In vitro such micropores were zoctonio, sp. (Bauer and Oberwinkler, r99oa). Further- present in the interaction of T. mesenterica witlt pen- more, the haustorial filament of Christiaruenia pallid,a ioqhorq, laeta, P. incamata and, Phlebia rad,iatabtt co.nld. penetrates to the cell of Phanerochaete creruea (Bres-) not be found in the interaction of T. mesmterica with Parm. Several micropores with direct cytoplasm-cy- Schizopora. parad.o,c&, Stereurl hirsutum atd. Diatrype stig- toplasm connections develop between the haustorial ma. However, only h Pmiophora laeta and P. ,inco,rnata filament and host cell (Bauer and Oberwinkler, r99ob). was the pore domain delimired by a more or less cir- Mycoparasitic interactions, with emphasis on the q?e cular arrangement of ER cisternae. Wall thickening species Trernella mesenterica Retz.: Fr., were studied. may be responsible for the nonmicropore interaction. The species occurs mainly on hardwoods with basidio- Key lryords: Heterobasidiomycetes, host-pansite in- mata often developing adjacent to fructifications of teraction, mycoparasitism, Peniophora laeto. TremelLo, Peniophora spp. (), especiatty those of the nlesentericq,, Tremella encephaLa, Tremella mycophaga, subgenus Gloeopeniophora, e.g., Peniophora laeta (Fr.) tremelloid haustorial cells Donk, Peniophora incamata (Pers. : Fr.) Karst. and Pen- io/hor& aurantiaca (Bres.) v. Höhn. & Litsch. (Bourdot INTRODUCTION and Galzin, r9z8; Jahn, 1979; Wong et at., 1985; Ban- doni, 1987). Therefore, (r979), Wong et al. (r985) While associarion with other fungi is common among Jahn and Bandoni (r987) suggested that T. mesenterica could. Tremella species, it is not clear that true mycoparasi- be a mycoparasite, but clear evidence is lacking. Tre- tism occurs (Bandoni, 1987). Specialized inreractive mzlla mcephala Pers.: Pers, grows on sanguino- cells, designated here as tremelloid haustorial cells, lenturn (Alb. & Schw. : Fr.) Fr.; the consists ofa firm, fleshy core surrounded by a getatinous layer. Accepted for publication Augusr 23, 1993. Bandoni (196r) demonstrated thar the fleshy core j be- Part 104 of the series "Studies in Hererobasidiomv.eres " longs to Stereum sangui,nolentum and, T. encephala forms

49 50 MYCoLocIA

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FrGS. 1 6. Transmission electron micrographs of interaction stages between and.l}].e }].ost Petuiophora laeta. 7, 2. Tremelloid haustorial cell (IH) with haustorial filament (H) attached to host cell (P). Note median section of micropore (arrow) between the apex of the hausto al frlament and the host cell. 2. The micropore of FlG. 1 at higher magnification. M, pore domain lvith ER cisterna. In FIG. 1, bar: I pm; in FIG. 2, bar:0.1 &m. 3,4. Median section through a micropore. The arows indicare the probably continuous plasma membrane through the Pore. Note that the pore domain (M) ar rhe hosr side (P) is delimited by a curved ER cisterna. H, haustorial fllament. 4. The micropore of FIG. 3 at higher ZUGMATER ET AL.: MycopARAstrrs][{ oF TREMELLA 5l

the gelatinous pafi. Tremella trycophaga G. W. Martin spore cultures of T. mesenterica, a small hymenal part grows on Aleurodiscus anlorphlts (Fr.) Schroet. The of the basidiocarp was attached to the inside ofa petri fructifications are pulvinate, discoid and can cover the plate lid, which was then placed over the medium. of the host by confluence (Martin, r94o). When could be observed on the medi- We present new data on the parasitic interaction of um, the lid was moved stepwise and finally replaced T. mesenterica, T. encephala and T. mycophaga. Further, by a sterile lid (Brough, ry74). After a few days, the host range of ?. mesentericq is testedwith Peniopho- colonies from single spores were visible in a dissecting ra laeta, P. i.ncatnata, PhLebia rad.iata Fr., Schizopora microscope and individually transferred to new plates. para.d.oxa (Schrad. : Fr .) Donk, SliIId' : Mycelium of T. mesmterica was obtained by crossing Fr.) Gray alJ.d. Diatryge stigma (Hoffm. : Fr.) Fr. monospore cultures from different basidiomata col- lected from Carpinus betulus. To determine the host spectrum, inocula 2-4 mm in diam of the potential MATERIALS AND METHODS fungal hosts were placed near the margin of a colony Specimms used..-TremelLa ruesenterica. GERMANY. of T. ruesenterica in a petri plate with MYP medium. BADEN-WÜRTTEMBERG: Stuttgart, Haldenwald near The same culture of T. nlesenterica was used for all Sonnenberg, on Car|iruß betulus L. adjacelt to Pen- experiments. Desired mixed stages were selected un- iophora laeta,8June 1987, 20 Nov. 1989, W. Zugm.aier der the Iight microscope and fixed for electron mi- 97, 158t Stuttgart Haldenwald near Sonnenberg, on croscopy. Carpiruls betulus, 15 Sept. 1988, W. Zugnaier 117; Living fungi and semithin sections ofembedded ma- Stuttgart, Schwälblesklinge near Sonnenberg, 5 May terial were examined with phase contrast optics. For 1989, I,y. Zugmaier 15). Tremella mcephala. GER- transmission electron microscopy, field collected and MANY. BADEN-WÜR.I.'rtugcrc: Kirnbachtal near Tü- cultured material was fixed in 270 gtutaraldehyde in bingen, on Pimrs sy lvestris, 20 Oct. 1988, W. Zugmaier 0.1 M sodium cacodylate buffer at pH 7.2 overnight 134. Tremella m)coph&g&. GERMANY. BADEN- or during several days. Following six transfers in 0.1 Wünrmlrstnc: Schwarzwald near Pfalzgrafenweiler, M sodium cacodylate buffer, the material was post- on Aleurodiscus axxorphus on Abies alba, 14 Oct. 1988, fixed in 17o osmium tetroxide in the same buffer for W. Zugmaier 13). Peniophorq lazra. GERMANY. Be- 2 h in the dark, washed in distilled water, and pre- DEN-WÜRTTEMBERc: Stuttgart, Haldenwald near Son- stained in lt% ]uranyl acetate solution for t h in the nenberg, on Carpinus betulus, 5 May 1989 , W. Zugmaier dark. After five washes in distilled water, the material 154. Peniophora 'incarnata. GERMANY. BA- was dehydrated in acetone, using l0 min changes at DEN-WÜRTTEMBERG: Stuttgart, Schwälblesklinge near 25Vo, 507o, 707o, 95Vo and 3 times in 10070 acetone. Sonnenberg, on Fagus »batica L., 10 May 1989, W. The material was embedded in Spurr's plastic (Spurr, Zugmaier 15 5. Phlebia radiata. CERMLNY. BA- 1969). Series of sections were cut on a Reichert ultra- DEN-WÜRTTEMBERG: Stuttgart, Schwätblesklinge near microtome using a diamond knife. Serial sections were Sonnenberg, on Fagus sylaati.ca, 10 Sept. 1989, I{. mounted on Formvar coated single slot copper grids, Zugmaier 157. Schizopora para.düea. GERMANY. BA- stained with lead citrate (Reynolds, r963) at room tem- DEN-WÜRTTEMBERc: Goldersbachtal near Tübingen- perature for 3-5 min, and washed again with distilled Bebenhausen, on Alnus glutinosa (L.) Gaert., 21 Oct. water. The thin sections were examined with a Zeiss 1989, E. Langer 2096. Sterewn äirsalum. GERMANY. EM 109 transmission electron microscope at 80 kV. BADEN-WüRTTEMBERG: Schönbuch, Bromberg, on robur L., 15 1989, W. Zugm.aier 142. Dia- Quercus Jan. RESULTS trtpe stignxa. GERMANY. BaorN-WÜxrrr.MsER.c: Stuttgart, Haldenwald near Sonnenberg, on Fagus syl- Obseraations from feld.-colkcted. rualerial.-Fructifica- uatica, 12 Sept. 1989, W. Zugmaier 156. tions of Tretnella mesenterica growing ot Car|inus betu- Ctitures of Tremella mesenterica, Peniophora laetq, P, l?rs adjaceDt lo Peniophora laeta were found several incarnata, Phlebia radiata, Schizopora parad,oxa, Stereum times, Under optimal wet and cool atmospheric con- hirsuturn arl,d. Diatrype stigma were grown on malt yeast ditions, orange accumulations of T. mesentericahyphae peptone agar (MYP; Bandoni, rgTz). To obtain mono- with conidia and very young fruitbodies were observed

magnification. In FIG. 3, bar : 0.5 pm; in Frc. 4, bar : 0.1 pm. 5. Apex of a haustorial filament (H) with median section of micropore. Electron-opaque material is located in the haustorial apex and extends through the micropore. The pore domain (M) at the host side (P) is delimited by a curved ER cisterna. Bar : 0.1 g.m. 6. Apex of a haustorial filamenr (H) wirh secrioned micropore attached to host cell (P). The pore domain (M) at the host side is surrounded by curved ER-cisternae. Note adjacent stacked ER-cisternae (arrows). Bar: 0.1 pm. 52 MYCor-ocIA

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FIGS.7 11. Transmission electron micrographs of interaction stages of Tremella mesmteica. T, 8. Adjacent serial sections. Haustorial filament (H) with presumed old micropore (arrowhead) penetrating the cell wall of the h,ost Peniophora la.eta (P). The host plasma membrane is folded back adjacent to the presumed old micropore and a thin secondary wall layer has developed (arrow). Bar : 0.1 pm. 9. A presumed original micropore (arrowhead) is branched terminally. Note the thin secondary host wall (arrow). P, cell of Peniophora laeta. Bat :0.1 pm. 10. Median section through a micropore between a ZUGMAIER ET AL.: MYCoPARASITISM oF TREMELLA 53 on P. laeta. In the rotting Carpinus betulus tissue and Cultural experimenß with Tremella mgsgn1g1i62.-J6 in fructifications of P. Laeta, hyphae of T. nxesenterica test the potential host spectrum of T. rnesentericq' one grew between host hyphae. The hyphae of T. mesen- mycelial strain of T. mesentericawas cdtivated together lerica possessed numerous tremelloid haustorial cells with Peniophora laeta, P. incamata, Phlebia rad.iala, Schi.- and often the haustorial filaments were attached to zopora ?arad,oxa, Stereum hirsulum and Diatrype stigma. host cells (FIG. 1), even in the zone of rott\ng Corpinus Numerous haustorial filaments were attached to cells betulus tissue. In the white core of the basidiomata, of all tested host fungi. Micropores with direct cyto- hyphae of Stereum sanguinolentutn were mixed with plasm-cytoplasm connections were present in inter- hyphae of Tremella encephala and many haustorial fil- actions of ?. mesenterica wit]f P. laeta, P. incarnata and. aments were attached to host hyphae (Frc. 14). The P. radiata (Ftc. 10). Stages in which the micropore was hymenium of Aleurodisctu amorphus was the zone of closed by a secondary wall layer at the host side were interactions with many haustorial filaments of TremeLla also observed. Thus, the interaction type was the same nrycophaga attached to host cells (FIc. 12). in vitro as in vivo. The pore domain at the host side, Since the host interactions of T. tnesenterica, T. en- however, was delimited by curved ER cisternae only cephala and T. mycophaga are rather similar, they need iD P. laeta and, P. incamata. not be described separately. In the initial stages of a In the interactions of T, ru,esenterica with Schizopora parasitic interaction, a haustorial filament invaded the pqrqd,oxa, Stereum hirsutum ar,d Diatrype stigma, a con- outer cell wall layers of a host cell (FIcs. 1-3,5, 12, tinuous micropore between haustorial filament and 14). A spurJike projection devoid of cell wall devel- host cell could not be found. An invagination of the oped from the haustorial apex and penetrated the host host plasma membrane and a prominent wall thick- wall (not illustrated). A single micropore finally con- ening of the host cell wall adjacent to the attached nected the cytoplasm of the haustorial filament with haustorial filament was always present (FIG. 11). that of the host cell (FIGS. 1-5, 13-16). The diam of the intermembrane space within the micropore was DISCUSSION 12-15 nm (FIcs. 2-5, 13, 15, 16). Onty under optimat Micropore.-It is clear from our study that more than sectioning conditions was it possible to observe the simple contact is involved in the mycoparasitism of continuation of the plasma membrane through the Tremella mesenterica, T. encephala and T. m2cophaga. micropore (Frcs. 3, 4, 15, l6). Sometimes the plasma Distinctive micropores with direct cytoplasmic contact membrane was slightly retracted on the pore openings are formed at the interface between the host and par- (FIGs.2, 13, 15, 16). Thus, occasionally, micropores asite. The type of host-parasite interface in the three had the appearance of simple dolipores (Ftc. 15). Of- Tremella species studied is essentially identical to that ten electron-opaque material rvas located in the apex of Tetragoniomlces uliginosus (Bauer and Oberwinkler, of the haustorial filament and apparently extended r99oa). The similarities include the development and through the micropore into the host cell (compare dimension of the micropore. As in T. uliginosus, an FIGS.5 and 13). In the interaction zone between T. electron-opaque matrix is often present in the cyto- rlesenterica and. Peniophora laeta cuwed cisternae of plasm within the micropore in the three species of smooth endoplasmic reticulum were associated with Tremella examined. Curved cisternae of ER are pres- the orifices of the micropore at the host side (FIGS. ent in the host cytoplasm at the interface between ?. 2-6). These configurations of ER were observed al- n esentericq and host cells of Peniophora laeta and, Pen- ready at the stage of haustorial penetration through iophora incaflLata. Since such cisternae are lacking at the host cell wall prior to the formation of the micro- the interface between T. ruesenterica and Phlebia rad,ia- pore. Adjacent stacked ER cisternae were sometimes ,a, their presence seems to be host dependent. Pez- observed (FIc. 6). Inall Trem.ella species studied stages iophora laeta arr,d. P. incamata were grouped by Eriksson were observed in which the host plasma membrane et al. G978) in the subgenus Gloeopeniophora. Perhaps was invaginated and the presumed original micropore other species of this taxon react similarly in the inter- was overgrown by a thin secondary host wall layer action with T, rnesenterica. (FIGS. 7-9). In some of these stages, the presumed original micropore was inflated orbranched terminally Micropore qnd, nonmicro|ore interactions,-lremelloid (Frc. 9). haustorial cells of Tremella nesenterica were attached

haustorial filament of T. mesenterica (H) and a hyphal cell of Phlebia rad,iata (PH\ showing the probably continous plasma membrane through the pore (arrows). Bar : 0.1 pm. 11. Haustorial filament of 7. ,nesenterica (H) attached to a h,?hal cell of D'iatrype stigma (D). Note the prominent wall thickening adjacent to the haustorial filament. Bar : 0.2 pm. 54 MYCor-oGrA

FIcs. 12-16. Transmission electron micrographs of Tramella mycophaga (Frcs. 12, 13) and T. ewephdla (Frcs.14-16). 12. Haustorial frlament (H) of T. mlcophaga attached (arrow) to a hyphal cell of Aleurod,iscus amorphu (A), TH, haustorial cell. Bar : I pm. 13. A micropore (arrow) connects the apex of a haustorial filament (H) of T. mycophaga and a hyphal cell of A. amorphu"s (A), Electron-dense material is situated in the pore and adjacent cytoplasmatic areas. Bar : 0.1 pm. 14. Haustorial filament (H) of Tremella mcephala attached (arrow) to a hyphal cell of (S'l). TH, haustorial cell. Bar ZUGMAIER ET AL.: MYCoPARASITISM oF TREMEI,LA 55 to hyphae of all tested host fungi. A single micropore 1972. Terrestrial occurrence of some aquatic hy- is present, however, only at the interface between the phomycetes. Canad. J. Bot.50: 2283-2288. tremelloid haustorial cell of Z mesenterica and host -. 1984. The Tremellales and Auriculariales: an al- cells of Peniophora Laeta, P. incamata and PhLebia ra- ternative classification. Trarß. M)col. Soc. Japan 25 489- d,iata. On the other hand, prominent wall thickenings -. 1985. Sirotrema: arl,ew in the . occurred adjacent to the attached haustorial filaments Canad.. Bot. 64: 668-676. by Schizopora parad,oxa, Stereum hirsutunx ar.d t!:.e as- J. -. 198?. Taxonomic overview of the Tremellales. Srad. comycete Diatrype stignla. These results may indicate Ivl1col.30:87-110. that species of Peniophora and related taxa (see Eriks- -. F. Oberwinlder, and A.-A. Bandoni. 1991. On son et al., 1978, r98r) are at least potential hosts of T. species of Filobasid.iaa associated with yuccas. SFreTr. nlesenterica. Apparently T. mesenterica is capabte of par- -, Appl. Microbiol. 14: 98-101. asitizing several wood decaying fungi. Those resistant Bauer, R., and F. Oberwinkler. 1990a. Direct cytoplasm- wood decaying species possibly are immune by virtue cytoplasm connection: an unusual host-parasite inter- of their capacity to rapidly form secondary wall Iayers. action of the tremelloid mycoparasite Tetragmtiomyces The potential hosts of T. mesenlerica and also the hosts uliginosus. Protoplo"sma 1 54: t 57-l 60. 1990b. Haustoria ofthe mycoparasitic of T, mcephala ar,d. T. mycophaga are sometimes also and-. heterobasidiomycete C hristiaß enia pallid,a. Cltolo gia 55 : able to stop or interrupt parasitic interactions by the 419-424. formation of secondary wall layers. -, Bezerra,J. L., andJ. W. Kimbrou8h. 1978. A new species Systemdic implicatioru. haustorial cells are of Tremella parasitic on RhJtidh)steriur/L rufulum. Canad,, typical of many species-Tremelloid of the Tremellales sensu Ban- J. Bot.56:3021-3033. doni (1984), Carcinomycetaceae (Oberwinkler and Bourdot, H., andA. Galzin. 1928. H)mikom)cötes de France. Marcel Bry, Sceaux, France. 764 pp. Bandoni, 198z), and Filobasidiaceae (Olive, 1968; Kwon- Brough, S. G. 1974. Trcmella globospora, in the freld and Chung, 1976; Bandoni et al., r99r). Most of these spe- in culture. Canad,. Bot.52: 1853-1859. cies are dimorphic with dolipores and cupulate caps J. Eriksson, J., K. Hjortstam, and L. Rl,varden. 1978. The (Oberwinkler and Bandoni, r98u; Oberwinkler et al., Corticiaceac of North Europe. Vol. 5. Mycoaciella-Pha- 1984; Bandoni, 1987). The host-parasite interface of nerochaete. Fungiflora, Oslo, Norway. Pp. 887-1047. five species has been studied. At the interface between and 1981. The Corticiaceae of North Trenella mesenterica, T. encephala, T, rrycophaga ar,d Europe. yol. 6. Phlebia-Sarcodontia. Fungiflora, Oslo, Tetragoniom)ces uliginosus (Bauer and Oberwinkler, -, Norway.-, Pp. i048-1276.-. r99oa) with their hosts only a single micropore is known Hess, W. M. 1969. Ultrastructure of onion roots infected to occur. At the interface between Christiansenia pal- j,it}l Plrmochaeta terrestris, a parasite. .4r2.er..7[. lida and the host seyeral micropores have been de- Bo-r.56:832-845. tected (Bauer and Oberwinkler, r99ob). Otherwise the Jahn, H. 1979. Pilze d,ie an Holz uachsen. Bussesche Ver- host-parasite interfaces in the species are similar. We lagshandlung, Herford. Germany. 268 pp. interpret the " Christiansenia interaction type" as de- Kwon-Chung, K.J. 1976. Morphogenesis of -pilobasidiella rived from the "TrernelLa-Tetragoniomyces interaction neoJormans, the sexual state of CryPtococcus neoformans. MlcoLogia 68: 827-833. type" (Bauer and Oberwinkler, r99ob). Similar micro- Martin, G. W. 1940. Some heterobasidiomycetes from east- pores at the host-parasite interface have not been re- erra Canada. Mycologia 32: 683-695. ported in other basidiomycetes. Metzler, B., F. Oberwinkler, and H. Petzold. 1989, Rfun- chogo,strema gen. nov. and Rhynchogastremaceae fam. ACKNOWLEDGMENTS nov. (Tremellales). S1st. Appt. Microbiot 12: 280-287. Oberwinl'ler, F., and R.J. Bandoni. 1981. Tetragoniomy- We thanl Dr. R. J. Bandoni for critically readin8 the manu- script and the Deutsche Forschungsgemeinschaft for finan- cetaceae: a new in the Tremellales, Canad.. J. BoL cial support. 59:1034-1040. and 1982. Carcinomycetaceae: a new fam- ily in the heterobasidiomycetes. Nordic Bot. 2:501- LITERATURE CITED J. -, 516. -. Bandoni, R. J. 1961. The ge )s Naematelia. Amer. Mid,l. and 1983, Trimorphomlces: a new genus in Naturalist 66: Z 1 9 -328. the Tremellaceae. 51§. Appl. MicrobioL 4: 105-113. -, -.

: 0.5 pm. 15, 16. Median sections through micropores between haustorial filaments of ?. encephala (H) and hyphal cells of S. sanguinolenlun (ST). Note that the pore membrane (arrows) is continuous with the plasma membrane of both cells. Bars : 0.1 pm. 56 MYcor.ocrA

R. Bauer, G. Deml, and L. Kisimova-Ho- 1968. An unusual heterobasidiomycete with Til- rovitz. 1984. The life-history of Crristiarßenia pallidn, letia,-like basidla. J. Elisha Mitchzll Sci. Soc.84: 261-266. a dimorphic,-, mycoparasitic heterobasidiomycete. M)- -.Reynolds, E, S. 1963. The use of lead citrate at high pH cologia 76: 9-22. as an electron opaque stain in electron microscopy. ,I. Cetl Biot. 17 208-212. andB. Lowy. 1981. Srygospora alba Mattin, zrr.y- Spurr, A. R. 1969. A low-viscosity epoxy resin embedding coparasitic heterobasidiomycete. Mlcologia 73: 1 108- medium for electron microscopy.rl Uttra.stract. Res.26i -, 1115. 31-43. Olive,L. S. 1946. New or rare heterobasidiomycetes from Wong, G.J., K. Wells, and R.J. Bandoni. 1985. Interfer- North Carolina. Il. J. Elisha Mit hetl Sai. Sor. 62: 65- tility and comparative morphological studies of Trernella 71. nesenterica. Mlcologia 77: 36-49.