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The aero-aquatic Helicodendron microsporum n. sp. from Mallorca, Spain
375
Mycol. Res. 104 (3) : 375–377 (March 2000). Printed in the United Kingdom.
The aero-aquatic Helicodendron microsporum n. sp. from Mallorca, Spain
Samir K. ABDULLAH1, Josep CANO2*, Enrique DESCALS3 and Josep GUARRO2 " Biology Department, College of Science, University of Basrah, Iraq. # Unitat de Microbiologia, Facultat de Medicina, Universitat Rovira i Virgili, 43201 Reus, Spain. $ Institut Mediterrani d’Estudis Avançats (CSIC-UIB), Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain. Accepted 29 July 1999.
A new aero-aquatic helicosporous hyphomycete, Helicodendron microsporum, is described and illustrated from decaying leaves submerged in a small artificial pond surrounded by Quercus ilex and Pinus halepensis in Mallorca, Spain. It is characterized by branched conidiophores with chains of hyaline conidia eventually forming white clusters which do not break up even at maturity. It also has small conidia (8–10 µm diam.) consisting of a 2–2n5 µm thick filament which coils 1n5–2 times counter-clockwise. The main characters of the species are compared with 14 similar hyalosporous Helicodendron species.
Helicodendron was established by Peyronel (1918) and typified by H. paradoxum, a fungus found on rotten trunks and branches lying on the banks of a mountain stream in Italy. The genus is characterized by disc or barrel-shaped conidia which proliferate as chains or clusters and consist of a filament coiled in three planes clockwise and\or counter-clockwise. Goos et al. (1985) monographed the genus and accepted 18 species with keys and illustrations. Abdullah (1987) described two more species on submerged plant debris from Japan (H. longisporum and H. japonicum). Goos & Uecker (1992) described H. minutum from bark of terrestrial origin from an undetermined tree in Hawaii. Several additional species have been recently described : H. websteri (Voglmayr & Fisher, 1997) on a variety of submerged leaves of deciduous trees in Britain ; H. praetermissum (Voglmayr, 1997 a) on submerged leaves and culms of monocotyledonous plants in Austria and the Netherlands ; H. coniferarum (Voglmayr, 1997 b) isolated from pine litter submerged in oligotrophic peat bog ditches in Austria ; and H. longitubulosum (Voglmayr, 1997 b) from an oak leaf submerged in a eutrophic woodland pond in Austria. During our studies on the aero-aquatic mycota of Spain (e.g. Abdullah, Guarro & Figueras, 1996 a ; Abdullah et al., 1996 b, 1997, 1998) an undescribed species of Helicodendron was isolated from submerged decaying Quercus ilex leaves in a small calcareous pond in Mallorca (Balearic Islands, Spain). This species is described and illustrated here with scanning electron micrographs.
* Corresponding author.
MATERIAL AND METHODS Submerged leaves were collected from a pond located in the Binifaldo public recreation area (Council of Escorca), NW Mallorca. It collects water from a seasonal stream draining a northwest-facing mixed evergreen oak (Quercus ilex) woodland with scattered pine (Pinus halepensis). The annual precipitation in the area is ca 1500 mm. The pond is at ca 500 m alt. It stores a maximum of 500 m$, and measures 50i25 m, with a maximum depth of 2 m, although this fluctuates significantly with the season. The impoundment is held by a small rock and concrete dam, and the bottom of the pond is lined with a layer of compacted lignite ash. These ashes were presumably of an acid reaction when installed, although this is apparently not reflected in the water analyses. Although the pond is exposed to sunlight and phytoplankton is present, it is mainly a heterotrophic ecosystem, with a heavy input of allochthonous (principally Quercus ilex) litter from overlying oak trees, which decomposes in the bottom. This creates anoxic conditions, which are tolerated by the aero-aquatic hyphomycetes (Fisher & Webster, 1981 ; Field & Webster, 1983). The pond is periodically dredged, and soon thereafter the photic zone becomes colonized by Characeae, but these become gradually choked by the accumulating sediment. Eight-year (1990–1997) physico-chemical records (read near the bottom) show pH values of 7n4–8, sometimes dropping to 6n8, a conductivity range from 350 to 700 µs cm−" and an alkalinity of (2–) 3–4(–6) meq l−". There is probably a significant input of untreated organic matter from grazing sheep as well as from visitors camping illegally, but N values have not been checked. The pond can be considered dystrophic.
New Helicodendron species from Spain
376
3 1
2
4
Figs 1–4. Helicodendron microsporum (IMI 375894). Figs 1, 2. Conidiophores bearing branched chains of conidia. Fig. 3. Clusters of conidia. Fig. 4. Chains of conidia. Bars l 10 µm.
TAXONOMY Helicodendron microsporum Abdullah, J. Cano, Descals & Guarro, sp. nov. (Figs 1–5) Etym : from Latin micro l small, spora l spore Coloniae in substrato naturale inconspicuae, coloniae in agaro maltoso (0n2 %) 1 cm diam. 14 dies (15 mC) crescentes, reversum luteo-album vel sub brunneum. Mycelium superficiale, hyalinum, ramosum, ex hyphis septatis, 1n5–2n0 µm latis compositum. Conidiophora micro-vel semimacronematosa, mononematosa, septata, ramosa, usque ad 200 µm longa, 2–2n5 µm lata. Cellulae conidiogenae blasticae, integratae. Conidia acropleurogena, hyalina vel luteoalba, 8–10 µm in diametro. Filamentum conidiale hyalinum, septatum, ad septa constrictum, 2–2n5 µm latum, 1n5–2 spiris plerumque sinistrorsum e centro visis torsivum. Holotypus IMI 375894, in foliis putridi ad Quercus ilex, Binifaldo! , Balearic Island, Hispania, leg. S. K. Abdullah et E. Descals, Feb. 1997. Fig. 5. Helicodendron microsporum (IMI 375894). Conidia and conidiophores. Bar l 10 µm.
Methods for field collection, isolation and studying the cultural characters of the fungus are described in Abdullah et al. (1998). SEM techniques were according to Figueras & Guarro (1988).
Colonies on the natural substratum inconspicuous ; on 0n1 % and 0n2 % MEA growing slowly, reaching 1 cm diam. in 2 wk at 15m ; colony reverse white turning pale yellow to pale brown. Aerial mycelium sparse, composed of branched, septate, hyaline hyphae 1n5–2 µm diam. Conidiophores hyaline, micronematous to semimacronematous, up to 200i2–2n5 µm, branched. Conidiogenous cells blastic, integrated. Conidia white in mass, acropleurogenous, 8–10 µm diam., produced in branched chains later becoming clustered. Conidial filament
S. K. Abdullah and others
377
Table 1. Main taxonomic characters of hyalosporous Helicodendron species* (amended from Goos et al., 1985).
Species
Conidial filament width (µm)
Number of coils
Diam. (µm)
Length (µm)
Direction of coiling
Microconidia
Teleomorph
Colony colour reverse on 0n1 % MEA
H. H. H. H. H. H. H. H. H. H. H. H. H. H. H.
6–10 5–7 4–5 2–3 5–8 1n5–2n5 5–8 4–6n5 2–3 4–6 3n7–5 2–2n5 4–6n5 5–6 4–5
3–5 5–12 8–14 1–2 2–20 2–5 2–6 5–8 4–12 12–23 (12–) 20–40 1n5–2 1n5–3 1n75–3n5 6–12
22–30 26–32 20–35 7–11 30–75 8–12 20–32 18–22 12–15 22–30 20–25 8–10 20–25 16–25 15–20
27–42 30–40 30–50 — 40–150 11–15 25–40 18n5–26n5 15–30 33–90 (50–) 90k150 (–170) — — — 25–40
Indeterminate Clockwise Clockwise Counter-clockwise Clockwise Indeterminate Counter-clockwise Clockwise Counter-clockwise Clockwise Counter-clockwise Counter-clockwise Indeterminate Indeterminate Counter-clockwise
k k j k j k k k k k j k j j j
k k k k j k k k k k k k j k j
— Pale yellow Green to dark green Fuscous to black Green to dark green Fuscous to black Pale yellow to pale brown Green to dark green Hyaline to pale yellow Green to dark green Brownish fuscous to blackish Pale yellow to pale brown Hyaline to white Hyaline to white Green to dark green
amazonense articulatum conglomeratum fractum giganteum hyalinum intestinale japonicum luteo-album longisporum longitubulosum microsporum paradoxum triglitziense tubulosum
Conidium
* H. indicum. The species has straw-coloured conidia. j Known. k Unknown.
hyaline, 2–2n5 µm wide, septate, constricted at septa, loosely coiled 1n5–2 times counter-clockwise. Phialoconidial state absent. Holotype : Spain, Balearic Islands, Mallorca, Binifaldo! , Escorca, on decaying Quercus ilex leaf submerged in a pond, Feb. 1997, S. K. Abdullah & E. Descals (IMI 375894, a dried culture on 0n2 % MEA). Isotype : CBS 100149. To date Helicodendron comprises 25 species, 15 of them with hyaline conidia (Table 1). H. microsporum is characterized by chains of hyaline conidia on branched conidiophores, eventually forming white conidial clusters which do not break even at maturity, and also by its small conidia. It can be easily diagnosed by its cultural character on 0n1 % and 0n2 % MEA, showing a pale yellow to pale brown reverse. The species shares this cultural characteristic with the hyalosporous H. articulatum, H. intestinale and H. luteo-album. The two former, however, can be easily distinguished from H. microsporum by their larger conidia and wider conidial filament. H. luteo-album has more or less the same filament width as in H. microsporum, but it differs in the number of coils, usually 4–12. Species similar to H. microsporum in having disc-shaped and hyaline conidia are H. fractum, H. paradoxum and H. triglitziense. The latter two are characterized by their larger conidia and wider conidial filament. The species most resembling, H. microsporum is H. fractum, but its conidial chains are easily broken up to form straight or curved propagules. In addition, H. fractum has a constantly fuscous to black colony reverse on 0n1 or 0n2 % MEA. Small conidia are also featured by H. minutum, but these are dark brown with a filament coiled 0n75 to 1n5 times. It is interesting to note that microconidial states are so far only known for hyalosporous Helicodendron species (Goos et al., 1985 ; Voglmayr, 1997 b). The three known teleomorphs of hyalosporous Helicodendron species are apothecial ascomycetes (Abdullah & Webster, 1981 ; Fisher & Webster, 1983). This work was supported by the ‘ Fundacio! Cie' ncia i Salut ’, Reus, Spain. We appreciate the limnological information on the pond under study provided by the Ecology staff at the University of the Balearic Islands.
REFERENCES Abdullah, S. K. (1987). Two new species of Helicodendron. Nova Hedwigia 44, 339–343. Abdullah, S. K., Cano, J., Descals, E. & Guarro, H. (1998). A new species of Helicoon from Mallorca, Spain. Mycologia 90, 916–920. Abdullah, S. K., Guarro, J. & Figueras, M. J. (1996 a). New and interesting Helicoon species from Spain. Mycotaxon 60, 449–454. Abdullah, S. K., Guarro, J., Figueras, M. J. & Descals, E. (1996 b). Spanish Hyphomycetes. XV. The aero-aquatic genus Helicodendron. Nova Hedwigia 63, 425–432. Abdullah, S. K., Guarro, J., Figueras, M. J. & Descals, E. (1997). Spanish Hyphomycetes. XVI. Some aero-aquatic conidial fungi. Mycotaxon 61, 311–318. Abdullah, S. K. & Webster, J. (1981). Lambertella tubulosa sp. nov., teleomorph of Helicodendron tubulosum. Transactions of the British Mycological Society 76, 261–263. Field, J. I. & Webster, J. (1983). Anaerobic survival of aquatic fungi. Transactions of the British Mycological Society 81, 365–369. Figueras, M. J. & Guarro, J. (1988). A scanning electron microscopic study of ascoma development in Chaetomium malaysiense. Mycologia 80, 298–306. Fisher, P. J. & Webster, J. (1981). Ecological studies on aero-aquatic Hyphomycetes. In The Fungal Community, its Organization and Role in the Ecosystem (ed. D. T. Wicklow & G. C. Carroll), pp. 709–730. New York & Basel : Dekker. Fisher, P. J. & Webster, J. (1983). The teleomorphs of Helicodendron giganteum and H. paradoxum. Transactions of the British Mycological Society 81, 646–659. Goos, R. D., Abdullah, S. K., Fisher, P. J. & Webster, J. (1985). The anamorph genus Helicodendron. Transactions of the British Mycological Society 84, 423–435. Goos, R. D. & Uecker, F. A. (1992). New species and additional records of fungi from Hawaii. Mycologia 84, 322–328. Peyronel, B. (1918). Micromiceti di val Germanasca. Quarto contributo alla flora micologica della Valli Valdesi del Piamonte. Nuovo Giornale Botanico Italiano N.S. 25, 405–464. Voglmayr, H. (1997 a). Helicodendron praetermissum sp. nov. and Spirosphaera calicigraminis sp. nov., aero-aquatic fungi on monocotyledonous debris. Canadian Journal of Botany 75, 1772–1777. Voglmayr, H. (1997 b). Two new aero-aquatic species of the hyphomycete genus Helicodendron from Austria. Plant Systematics and Evolution 205, 185–193. Voglmayr, H. & Fisher, P. J. (1997). Helicodendron fuscum and its allies. Mycological Research 101, 1112–1126. Corresponding Editor : K. D. Hyde
Mycol. Res. 104 (3) : 375–377 (March 2000). Printed in the United Kingdom.
The aero-aquatic Helicodendron microsporum n. sp. from Mallorca, Spain
Samir K. ABDULLAH1, Josep CANO2*, Enrique DESCALS3 and Josep GUARRO2 " Biology Department, College of Science, University of Basrah, Iraq. # Unitat de Microbiologia, Facultat de Medicina, Universitat Rovira i Virgili, 43201 Reus, Spain. $ Institut Mediterrani d’Estudis Avançats (CSIC-UIB), Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain. Accepted 29 July 1999.
A new aero-aquatic helicosporous hyphomycete, Helicodendron microsporum, is described and illustrated from decaying leaves submerged in a small artificial pond surrounded by Quercus ilex and Pinus halepensis in Mallorca, Spain. It is characterized by branched conidiophores with chains of hyaline conidia eventually forming white clusters which do not break up even at maturity. It also has small conidia (8–10 µm diam.) consisting of a 2–2n5 µm thick filament which coils 1n5–2 times counter-clockwise. The main characters of the species are compared with 14 similar hyalosporous Helicodendron species.
Helicodendron was established by Peyronel (1918) and typified by H. paradoxum, a fungus found on rotten trunks and branches lying on the banks of a mountain stream in Italy. The genus is characterized by disc or barrel-shaped conidia which proliferate as chains or clusters and consist of a filament coiled in three planes clockwise and\or counter-clockwise. Goos et al. (1985) monographed the genus and accepted 18 species with keys and illustrations. Abdullah (1987) described two more species on submerged plant debris from Japan (H. longisporum and H. japonicum). Goos & Uecker (1992) described H. minutum from bark of terrestrial origin from an undetermined tree in Hawaii. Several additional species have been recently described : H. websteri (Voglmayr & Fisher, 1997) on a variety of submerged leaves of deciduous trees in Britain ; H. praetermissum (Voglmayr, 1997 a) on submerged leaves and culms of monocotyledonous plants in Austria and the Netherlands ; H. coniferarum (Voglmayr, 1997 b) isolated from pine litter submerged in oligotrophic peat bog ditches in Austria ; and H. longitubulosum (Voglmayr, 1997 b) from an oak leaf submerged in a eutrophic woodland pond in Austria. During our studies on the aero-aquatic mycota of Spain (e.g. Abdullah, Guarro & Figueras, 1996 a ; Abdullah et al., 1996 b, 1997, 1998) an undescribed species of Helicodendron was isolated from submerged decaying Quercus ilex leaves in a small calcareous pond in Mallorca (Balearic Islands, Spain). This species is described and illustrated here with scanning electron micrographs.
* Corresponding author.
MATERIAL AND METHODS Submerged leaves were collected from a pond located in the Binifaldo public recreation area (Council of Escorca), NW Mallorca. It collects water from a seasonal stream draining a northwest-facing mixed evergreen oak (Quercus ilex) woodland with scattered pine (Pinus halepensis). The annual precipitation in the area is ca 1500 mm. The pond is at ca 500 m alt. It stores a maximum of 500 m$, and measures 50i25 m, with a maximum depth of 2 m, although this fluctuates significantly with the season. The impoundment is held by a small rock and concrete dam, and the bottom of the pond is lined with a layer of compacted lignite ash. These ashes were presumably of an acid reaction when installed, although this is apparently not reflected in the water analyses. Although the pond is exposed to sunlight and phytoplankton is present, it is mainly a heterotrophic ecosystem, with a heavy input of allochthonous (principally Quercus ilex) litter from overlying oak trees, which decomposes in the bottom. This creates anoxic conditions, which are tolerated by the aero-aquatic hyphomycetes (Fisher & Webster, 1981 ; Field & Webster, 1983). The pond is periodically dredged, and soon thereafter the photic zone becomes colonized by Characeae, but these become gradually choked by the accumulating sediment. Eight-year (1990–1997) physico-chemical records (read near the bottom) show pH values of 7n4–8, sometimes dropping to 6n8, a conductivity range from 350 to 700 µs cm−" and an alkalinity of (2–) 3–4(–6) meq l−". There is probably a significant input of untreated organic matter from grazing sheep as well as from visitors camping illegally, but N values have not been checked. The pond can be considered dystrophic.
New Helicodendron species from Spain
376
3 1
2
4
Figs 1–4. Helicodendron microsporum (IMI 375894). Figs 1, 2. Conidiophores bearing branched chains of conidia. Fig. 3. Clusters of conidia. Fig. 4. Chains of conidia. Bars l 10 µm.
TAXONOMY Helicodendron microsporum Abdullah, J. Cano, Descals & Guarro, sp. nov. (Figs 1–5) Etym : from Latin micro l small, spora l spore Coloniae in substrato naturale inconspicuae, coloniae in agaro maltoso (0n2 %) 1 cm diam. 14 dies (15 mC) crescentes, reversum luteo-album vel sub brunneum. Mycelium superficiale, hyalinum, ramosum, ex hyphis septatis, 1n5–2n0 µm latis compositum. Conidiophora micro-vel semimacronematosa, mononematosa, septata, ramosa, usque ad 200 µm longa, 2–2n5 µm lata. Cellulae conidiogenae blasticae, integratae. Conidia acropleurogena, hyalina vel luteoalba, 8–10 µm in diametro. Filamentum conidiale hyalinum, septatum, ad septa constrictum, 2–2n5 µm latum, 1n5–2 spiris plerumque sinistrorsum e centro visis torsivum. Holotypus IMI 375894, in foliis putridi ad Quercus ilex, Binifaldo! , Balearic Island, Hispania, leg. S. K. Abdullah et E. Descals, Feb. 1997. Fig. 5. Helicodendron microsporum (IMI 375894). Conidia and conidiophores. Bar l 10 µm.
Methods for field collection, isolation and studying the cultural characters of the fungus are described in Abdullah et al. (1998). SEM techniques were according to Figueras & Guarro (1988).
Colonies on the natural substratum inconspicuous ; on 0n1 % and 0n2 % MEA growing slowly, reaching 1 cm diam. in 2 wk at 15m ; colony reverse white turning pale yellow to pale brown. Aerial mycelium sparse, composed of branched, septate, hyaline hyphae 1n5–2 µm diam. Conidiophores hyaline, micronematous to semimacronematous, up to 200i2–2n5 µm, branched. Conidiogenous cells blastic, integrated. Conidia white in mass, acropleurogenous, 8–10 µm diam., produced in branched chains later becoming clustered. Conidial filament
S. K. Abdullah and others
377
Table 1. Main taxonomic characters of hyalosporous Helicodendron species* (amended from Goos et al., 1985).
Species
Conidial filament width (µm)
Number of coils
Diam. (µm)
Length (µm)
Direction of coiling
Microconidia
Teleomorph
Colony colour reverse on 0n1 % MEA
H. H. H. H. H. H. H. H. H. H. H. H. H. H. H.
6–10 5–7 4–5 2–3 5–8 1n5–2n5 5–8 4–6n5 2–3 4–6 3n7–5 2–2n5 4–6n5 5–6 4–5
3–5 5–12 8–14 1–2 2–20 2–5 2–6 5–8 4–12 12–23 (12–) 20–40 1n5–2 1n5–3 1n75–3n5 6–12
22–30 26–32 20–35 7–11 30–75 8–12 20–32 18–22 12–15 22–30 20–25 8–10 20–25 16–25 15–20
27–42 30–40 30–50 — 40–150 11–15 25–40 18n5–26n5 15–30 33–90 (50–) 90k150 (–170) — — — 25–40
Indeterminate Clockwise Clockwise Counter-clockwise Clockwise Indeterminate Counter-clockwise Clockwise Counter-clockwise Clockwise Counter-clockwise Counter-clockwise Indeterminate Indeterminate Counter-clockwise
k k j k j k k k k k j k j j j
k k k k j k k k k k k k j k j
— Pale yellow Green to dark green Fuscous to black Green to dark green Fuscous to black Pale yellow to pale brown Green to dark green Hyaline to pale yellow Green to dark green Brownish fuscous to blackish Pale yellow to pale brown Hyaline to white Hyaline to white Green to dark green
amazonense articulatum conglomeratum fractum giganteum hyalinum intestinale japonicum luteo-album longisporum longitubulosum microsporum paradoxum triglitziense tubulosum
Conidium
* H. indicum. The species has straw-coloured conidia. j Known. k Unknown.
hyaline, 2–2n5 µm wide, septate, constricted at septa, loosely coiled 1n5–2 times counter-clockwise. Phialoconidial state absent. Holotype : Spain, Balearic Islands, Mallorca, Binifaldo! , Escorca, on decaying Quercus ilex leaf submerged in a pond, Feb. 1997, S. K. Abdullah & E. Descals (IMI 375894, a dried culture on 0n2 % MEA). Isotype : CBS 100149. To date Helicodendron comprises 25 species, 15 of them with hyaline conidia (Table 1). H. microsporum is characterized by chains of hyaline conidia on branched conidiophores, eventually forming white conidial clusters which do not break even at maturity, and also by its small conidia. It can be easily diagnosed by its cultural character on 0n1 % and 0n2 % MEA, showing a pale yellow to pale brown reverse. The species shares this cultural characteristic with the hyalosporous H. articulatum, H. intestinale and H. luteo-album. The two former, however, can be easily distinguished from H. microsporum by their larger conidia and wider conidial filament. H. luteo-album has more or less the same filament width as in H. microsporum, but it differs in the number of coils, usually 4–12. Species similar to H. microsporum in having disc-shaped and hyaline conidia are H. fractum, H. paradoxum and H. triglitziense. The latter two are characterized by their larger conidia and wider conidial filament. The species most resembling, H. microsporum is H. fractum, but its conidial chains are easily broken up to form straight or curved propagules. In addition, H. fractum has a constantly fuscous to black colony reverse on 0n1 or 0n2 % MEA. Small conidia are also featured by H. minutum, but these are dark brown with a filament coiled 0n75 to 1n5 times. It is interesting to note that microconidial states are so far only known for hyalosporous Helicodendron species (Goos et al., 1985 ; Voglmayr, 1997 b). The three known teleomorphs of hyalosporous Helicodendron species are apothecial ascomycetes (Abdullah & Webster, 1981 ; Fisher & Webster, 1983). This work was supported by the ‘ Fundacio! Cie' ncia i Salut ’, Reus, Spain. We appreciate the limnological information on the pond under study provided by the Ecology staff at the University of the Balearic Islands.
REFERENCES Abdullah, S. K. (1987). Two new species of Helicodendron. Nova Hedwigia 44, 339–343. Abdullah, S. K., Cano, J., Descals, E. & Guarro, H. (1998). A new species of Helicoon from Mallorca, Spain. Mycologia 90, 916–920. Abdullah, S. K., Guarro, J. & Figueras, M. J. (1996 a). New and interesting Helicoon species from Spain. Mycotaxon 60, 449–454. Abdullah, S. K., Guarro, J., Figueras, M. J. & Descals, E. (1996 b). Spanish Hyphomycetes. XV. The aero-aquatic genus Helicodendron. Nova Hedwigia 63, 425–432. Abdullah, S. K., Guarro, J., Figueras, M. J. & Descals, E. (1997). Spanish Hyphomycetes. XVI. Some aero-aquatic conidial fungi. Mycotaxon 61, 311–318. Abdullah, S. K. & Webster, J. (1981). Lambertella tubulosa sp. nov., teleomorph of Helicodendron tubulosum. Transactions of the British Mycological Society 76, 261–263. Field, J. I. & Webster, J. (1983). Anaerobic survival of aquatic fungi. Transactions of the British Mycological Society 81, 365–369. Figueras, M. J. & Guarro, J. (1988). A scanning electron microscopic study of ascoma development in Chaetomium malaysiense. Mycologia 80, 298–306. Fisher, P. J. & Webster, J. (1981). Ecological studies on aero-aquatic Hyphomycetes. In The Fungal Community, its Organization and Role in the Ecosystem (ed. D. T. Wicklow & G. C. Carroll), pp. 709–730. New York & Basel : Dekker. Fisher, P. J. & Webster, J. (1983). The teleomorphs of Helicodendron giganteum and H. paradoxum. Transactions of the British Mycological Society 81, 646–659. Goos, R. D., Abdullah, S. K., Fisher, P. J. & Webster, J. (1985). The anamorph genus Helicodendron. Transactions of the British Mycological Society 84, 423–435. Goos, R. D. & Uecker, F. A. (1992). New species and additional records of fungi from Hawaii. Mycologia 84, 322–328. Peyronel, B. (1918). Micromiceti di val Germanasca. Quarto contributo alla flora micologica della Valli Valdesi del Piamonte. Nuovo Giornale Botanico Italiano N.S. 25, 405–464. Voglmayr, H. (1997 a). Helicodendron praetermissum sp. nov. and Spirosphaera calicigraminis sp. nov., aero-aquatic fungi on monocotyledonous debris. Canadian Journal of Botany 75, 1772–1777. Voglmayr, H. (1997 b). Two new aero-aquatic species of the hyphomycete genus Helicodendron from Austria. Plant Systematics and Evolution 205, 185–193. Voglmayr, H. & Fisher, P. J. (1997). Helicodendron fuscum and its allies. Mycological Research 101, 1112–1126. Corresponding Editor : K. D. Hyde