Teleomorphs of three aquatic hyphomycetes

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  • Trans. Br, mycol. Soc. 77 (3), 475-483 (1981)

    [ 475 ]Printed in Great Britain

    TELEOMORPHS OF THREE AQUATIC HYPHOMYCETESBy S. K. ABDULLAH*, E. DESCALS AND J. WEBSTER

    Department of Biological Sciences, University of Exeter

    The teleomorphs of Tricladium splendens, Articulospora tetracladia and Dimorphosporafoliicola are described and illustrated. They are respectively Hymenoscyphus splendens n.sp.,Hymenos cyphus tetracladius n .sp, and Hymenoscyphus foliicola n.sp .

    Webster & Descals (1979, 1981) have listed theknown connexions between 'Ingoldian' aquaticH yphomycete anamorphs and their teleomorphs.The present paper describes three further con-nexions. In most cases, the teleomorphs have beencollected on twigs, leaves and cupules fromstreams and ponds. Single ascospore isolates havebeen prepared by techniques described in Webster& Descals (1979).

    In two cases (T ricladium splendens Ingold andDimorphosporafoliicola Tubaki), conidia developeddirectly on the surface of dry 0'1 % malt extractagar cultures, but in Articulospora tetracladia,conidial development only took place when stripsof culture were immersed in water.

    Hymenoscyphus splendens sp.nov. (Figs 1-2,3A- C)

    Apothecia disseminata, superficialia, eburnea velcremea, siccanteapallide-lutea vel brunnea, cylindrata,0'8-1 '2 mm alta, 0'6-1 '0 mm diam , Hymenium circa100 pm latum. Excipulum medullare textura intricata,ex hyphis intertextis 3-4 pm latis compositum;excipulum externum textura globulosa, ex stratispaucis cellarum, ad 30 pm diam compositum. Cellulaead marginem disci plerumque elongatae in capilloscylindratos laeves, non-ramosos, sparsim septatos ethyalinos. Asci octospori, cylindrati vel clavati, 40-80 x7-10 pm ; porus cyaneusin KI. Ascosporae fusiformes,ellipticae vel inaequilaterales, unicellulae 7-10(-13) x2'5-3'5 pm, supra biseriatae, infra uniseriatae. Para-physes cylindratac, non attingentes ascos, apicibusgranulatis, vix septatae, 2-3 pm latae ,

    In cupulis Fagi sy loaticae, Waggoners' Wells, propeHindhead, Surrey, Anglia,mensaeFebruario, 1979,leg.S. K. Abdullah. Specimen IMI 255256typus est.

    Te/eomorph (Figs 1, 3A-C): Apothecia scattered,superficial, white to creamy, drying pale yellow tolight brown, cylindrical to funnel-shaped with awide cylindrical base, 0'8-1 '2 mm tall and0'6-1 '0 mm in diam . Hymenium about 100 pmth ick; medullary excipulum of textura intricata,

    * Present address: Department of Biology, Collegeof Science, University of Basrah, Basrah, Iraq.

    interwoven hyphae 3-4 pm wide; ectal excipulumof textura globosa, composed of a few layers ofisodiametric thin-walled cells, up to 30 pm indiam; cells towards the margin of the disk 'fre-quently elongated into smooth cylindrical blunthairs, unbranched, sparsely septate and hyaline.Asci 8-spored, cylindrical-clavate, 48-80 x 7-10pm, pore staining deep blue in Melzer's reagent.Ascospores fusiform elliptical or inequilateral,r-celled, 7-10(-13) x 2'5-3'5 pm in size, biseriate.above, un iseriate below. Paraphyses cylindrical,not exceeding the asci, with granular apices,scarcely septate, 2'5-3 pm wide.

    Specimens examined: Holotype on cupules of Fagussyluatica inoculated with conidia derived from asco-spores. Apothecia originally collected from cupules ofFagus from Waggoners' Wells, Hindhead, Surrey,England, February 1979. S. K. Abdullah. The typespecimen has been deposited as Herb. IMI 255256.Isotypes are preserved in Herb. Exr, No. 3587.

    One of us (S.K.A.) collected cupules of beech(Fagus sy luatica L.) from a shallow pond atWaggoners' Wells, Hindhead, Surrey, on 3 Feb-ruary 1979. The cupules were brought to Exeter,rinsed in water, and incubated in a plastic luncheonbox lined with moist blotting paper at 15 C forthree weeks. Short-stalked, cream-coloured ape-thecia developed on two of the cupules. When theapothecia were ripe, ascospores were projected onto 0'1 % malt extract agar with added 0'008 %Crystamycin, The ascospores germinated over-night and a series of single and multi-spore cul-tures were prepared on further plates of the samemedium and of 2 % malt extract agar . Theseplates were incubated for 7 days at 15 under NUV(phillips Black Light). In all cultures, the charac-teristic conidia of Tricladium splendens Ingold(1942) were observed, developing on aerial coni-diophores (Fig. 1). The identity of these conidiahas kindly been confirmed by Professor C. T.Ingold. Since no type material of this fungus hasbeen designated, these cultures (Herb. Exr. No.3587) are now proposed as lectotype specimens,

  • 476 Te/eomorphs of aquatic hyphomycetes

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    Fig. 1. Hymenoscyphus splendens (Herb. Exr. 3587):(A) V.S. portion of apothecium. (B)Asci,ascosporesand paraphyses.

    and have been deposited at the CommonwealthMycological Institute, Herb. 1M!.

    In June and September 1979, further col1ec-tions on beech cupules were made from the samelocality. Single and multi-spore cultures from thediscomycete have also produced conidia ofT. splendens.

    An experiment has been designed to determine

    whether the fungus is homothal1ic or heterothallicby crossing different isolates derived from singleascospores. The crosses were made by inoculatingsterilized beech cupules placed in moist sterilesand in 6 em Petri dishes incubated at 10-150.After 4-6 months, apothecia developed in certainpairings. The results of the crosses show that thefungus is heterothallic, since apothecia developed

  • S. K. Abdullah, E. Descals andJ. Webster 477

    Fig. 2. Hymenoscyphus splendens: conidiophores and conidia of TricIadium splendens derived from asingle ascospore culture. Herb. Exr. 3587.

    only from crosses between isolates of differentascospores, and did not develop in culturesderived from a single ascospore.

    Descals (1978) has shown that several otherisolates of T. splendens produce, in culture, aphialosporic spermatial state, and although wehave no proof, we suspect that they may play arole in sexual reproduction.

    Our fungus has been compared with specimensof Hymenoscyphus fagineus (Pers. ex Fr.) Dennisfrom Herb. K, which grows on dry beech cupuleson land (Carre, 1964), but the two fungi are dis-tinct. Our measurements of H. [agineus ascosporesrange from 8'5-12"5 x 3'5-5 pm, and are thereforeappreciably wider than tho se of H. splendens. Theanchoring hyphae described by Dennis (1956) forHelotium fag ineum were not observed, and theectal excipulum was distinct.

    Tricladium splendens is known to occupy a widerange of habitats. Its spores are well-knownelements of the spora of rapidly-flowing streamsand foam (Ingold, 1942; Iqbal, 1972), colonizingdecaying leaves and twigs of different plants. It hasbeen regarded as a typical ' aquatic hyphomycete'.

    We also find it very commonly on wood and leavesdredged from muddy stagnant ponds and ditches,and it fruits readily on such materials whenincubated in moist chambers. In this respect, itresembles the aero-aquatic fungi which usuallyoccur in these habitats. Bandoni (1972) recordedT . splendens on decaying leaves of Acer macro-phyllum and Quercus robur collected from highwell-drained sites at some distance from streamsor water bodies. Furthermore, Sanders & Webster(1978) found that T. splendens could survive for aperiod of 15 weeks in a terrestrial environment oninfected leaf disks as well as on naturally colonizedleaves from streams. Its apothecial state releasesair-borne ascospores, and it can therefore beregarded as terrestrial. In view of the wide rangeof sub strata on which the anamorph is known tooccur, we would expect the teleomorph to befound on other woody substrata.

    Hymenoscyphus tetracladius sp.nov, (Fig. 4)Apothecia solitaria vel caespitosa, alba, primordiiscylindratis crescentia, ad basim hirsuta, maturitate incupulam infundibuliformem expandentia, minuta,

  • Teleomorphs of aquatic hyphomycetes

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    Fig. 3. A-C, Hymenoscyphus splendens, and D, Hymen oscyphus [oliicola: (A) Young apothecia of H.splendens grown in culture on a beech cupule. (B) V.S. apothecium. (C) Asci and paraphyses.(D) Apothecium of Hymenoscyphus foliicola in culture on a beech cupule.

    circa 200-300 pm diam et 300 pm alta. Asci clavati,octospori, 50-70 x 9-11 usn, poro cyaneo in KI.Ascosporae ovatae vel fusiformes, hyalinae, 6-10 x3-4'5 pm, aliquando uniseptatae, biseriatae. Para-physes ramosae infra, 2-2 '5 pm latae.

    In foliis submersis Fagi, Quercus et Salicis, camerahumida inconditi s. Specimen in Herb. Exr. No.3590 (IM1 255260) ad cupulas Fagi syluaticae cultum,typus est.

    Apotheciasingle or in clu sters, white, developingfrom cylindrical primordia, hairy at the base, atmaturity expanding into a funnel-shaped cup,about 2co-300 jim diam and 300 pm high. Asci

    clavate, 50-70 x 9-11 /lm in size, pore stainmgdeep blue in Melzer's reagent, S-spored. Asco-spores oval to fusiform, hyaline, 6-10 x 3-4'5 /lm,occasionally r-septate, biseriate. Paraphyses bran-ched below, 2-2'5 /lm wide.

    Sp ecimens examined: On submerged leaves of Fagus,Quercus and Salix after incubation in moist chambers.Herb. Exr. No. 3590 is the T ype Specimen (apotheciagrown in culture on cupules of Fagus sylvatica) (1M1255260).

    Several collections of a minute white disco-mycete from various substrates have been made.All these collections have been shown to be the

  • S. K. Abdullah, E. Descals and]. Webster 479

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    Fig. 4. Hymenoscyphus tetracladius: (A) Outline of apothecia from culture on beech cupule. (B) Para-physes. (C) Excipulum in optical section and in surface view. (D) Ascospores and asci. (E) Conidiaand conidiophores in culture derived from an ascospore. (B-E) to same scale.

    perfect state of a fungus which, in our

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