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The Indian summer of a mycologist
Volume 10, Part 3, August 1996
THE INDIAN SUMMER OF A MYCOLOGIST C.T.INGOLD 12 Chiltern Close, Benson, Oxon OX10 6LG
Having retired in 1972 at the age of 67, I was, for the next few years, still much concerned with universities abroad through the Inter-University Council for Higher Education Overseas, with which I had long been associated. During this period, my only contributions to mycology were a 'Guide to Aquatic Hyphomycetes' (1975)* and a note on spore discharge in Acrospermum (1978) which closely mirrored my first paper on fungi (1928). In 1977, having moved to Benson in Oxfordshire, I began to cast around for a mycological project. The Benson Brook, a chalk stream , was a poor source of aquatic hyphomycetes. Further, working at home, I could not match the splendid work on these organisms in train elsewhere. My first move in a new direction came with a passing interest in Flammulina velutipes (Curt.) Karst., then locally abundant on the numerous stumps of elm killed by Ophiostoma ulmi (Buisman) Nannf. In the winter of 1978-79 Benson airfield had its lowest recorded temperature, and basidiomes of F. velutipes were frozen solid. Nevertheless spore liberation resumed as soon as they thawed. This encouraged me to make some simple experiments on the almost unique resistance of this agaric to freezing (1981) and led me to consider other basidiomycetes that shed their spores in the depth of winter. Conspicuous among these were the jelly fungi. In studying these I was soon deflected to a consideration of their microconidial stages which seemed to have been inadequately described. In Dacrymycetaceae the microconidia occur either singly or in clusters, and then it is clear that they are formed in succession side by side (1983). Basidiospores in this family are often described as septate. However, it became clear that, at the moment of liberation, they are always unicellular although thereafter, transverse septa rapidly Footnote * Dates in brackets refer to papers solely in the author's name
form. Indeed, my many observations of a wide range of basidiomycetes suggest that when a ballistospore leaves its sterigma, it is invariably non-septate. I soon became especially interested in Auriculariales, Tremellales and Tulasnellales cultures of which, derived from basidiospores, were either yeast-like as in Tremella spp (1982b, 1982c) or mycelial as in most genera. Frequently their hyphae formed microconidia which were Cshaped in Auricularia spp (1982a), Exidia glandulosa (1982b), Myxarium nucleatum (1984b), Exidiopsis effusa (1992b) , Platyglo ea effusa (1988a) and Dicellomyces scirpi (1985), but globose in Helicogloea lagerheimii (1992a), stellate in Tulasnella cystidiophora (1984c) and bacilliform in Exidia recisa (1995b). The interesting feature of all of these conidia is that they are produced in succession, one behind the other, as in an ascomycete phialide. It appeared that the pattern of germination of liberated basidiospores depended on local conditions (1984c). In all the jelly fungi I have studied, basidiospores on fresh 0.2% malt agar invariably germinated with hyphal germ-tubes, whereas those germinating close to an established parent mycelium tended to produce microconidia immediately. Further, in all species the basidiospores stranded on a parent hymenium mostly germinated by repetition, a process unknown in Dacrymycetaceae. The tendency of spores germinating close to a mycelium of the same species to produce a sporing stage directly is, apparently, a general phenomenom exhibited by such diverse fungi as Conidiobolus spp. (1986a) and Bulgaria inquinans (1986c). The epimycetes on jelly fungi also attracted my attention. From inverted basidiomes of Auricularia auricula-judae Schroet. colonies developed on agar below from spores liberated actively by these surface fungi. As was to be expected, Sporobolomyces spp and, to a lesser degree, Tilletiopsis spp were abundant. Less expected were several species of Conidiobolus
Volume 10, Part 3, August 1996 (1991b). Almost invariably present was Itersonilia perplexans Derf, and this proved of interest especially in relation to the process of spore liberation (summary in 1991b). The fairly large Buller drop in this species takes relatively long (30-50 sec) to grow to full size before the ballistospore suddenly disappears from its sterigma. I watched the whole process on many occasions under high power and for the first time observed the adaxial liquid blob that arises on the side of the spore as the Buller drop is growing. I was able to interest John Webster in this fungus, and work by him and his associates has led to a revealing picture of ballistospore liberation (Webster & Chien, 1990). Among the epimycetes of Jew's Ear I encountered a mirror-image yeast that did not fit a described genus. This was named Bensingtonia ciliata (1986b) in honour of the village in which I live, the original name of which was Bensington. More recently (Boekhout, 1991) five further species of the genus have been recognised. In the mid eighties, having developed a general interest in heterobasidiomycetes, I watched germination of teliospores of Ustilago avenae from Arrhenatherum elatius, and was surprised to note that the lowermost cell of the basidium was often entirely enclosed by the teliospore, so that the basidiospore from it had to emerge through the thick teliospore wall. This encouraged me to germinate the smut spores of several other species of Ustilago. It became clear that there were several different patterns of teliospore germination, but these could nearly always be interpreted as variations on the theme of a 4celled basidium (1984a, 1989b, 1995a). This work on smuts extended and soon was responsible for most of my mycological activity, involving ultimately watching the germination of teliospores in over 50 species spread among 10 genera of Ustilaginaceae and 5 genera of Tilletiaceae. In the past few years I have had a special interest in the form of the basidium in certain tilletiaceous genera namely Tilletia (1987), Urocystis (1987, 1989a) and Melanotaenium (1988b). It seems to me that in Tilletia the basidium is basically a condensed branched structure with a tendency towards dichotomy. This idea had further support from the surprising discovery that in T. hyalospora Massee (now Ingoldiomyces hyalosporus Vanky) (1995c) the basidium has ballistosporic
basidiospores instead of filamentous ones not actively liberated. The basidium in that smut bears one or two spores, and in the two-spored types there is a single dichotomy. I now consider that such a basidium represents the primitive condition in Tilletiaceae. Initially, in my study of smuts, I relied on collections made during daily country walks, but later depended on material sent by friends, and, in the past few years, particularly on the exsiccata of his world-wide collections generously put at my disposal by Dr K. Vanky, In the early nineteen nineties I became interested in the liberation of ballistospores in Tilletiopsis spp and in the similar anamorphs of Tilletia spp and Tilletaria anomala Bandoni & Johri. In all these it could be shown that, although most ballistospores were set free singly, a considerable number sprang from their sterigmata in bundles of 2-6 (1991a, 1992c, 1996). In spite of the somewhat haphazard nature of my mycological studies in Benson, it seems to me that certain contributions to the knowledge of heterobasidiomycetes have been made namely: the elucidation of the nature of microconidia in jelly fungi; the exploration of the epimycetes of Jew's Ear; the recognition of Itersonilia perplexans as a useful tool in the study of ballisto spore liberation; the indication that the pattern of basidiospore germination depends on local conditions; the interpretation of the variations in teliospore germination in Ustilaginaceae in terms of a four-celled basidium; the recognition of the basidium in Tilletia as a branched structure, together with the suggestion that T. hyalospora Massee represents the primitive state in Tilletiaceae; and the observation that in Tilletiopsis ballistospores can be set free in bundles as well as singly. Since 1977 my work has been carried out in a small room at home. It would not have been possible if my old Department, through Jane Nicklin, had not kept me supplied with sterile Petri dishes and agar. Also, I owe a great debt to John Webster who not only helped with photography at his Exeter laboratory, but was also a source of encouragement and helpful criticism. Perhaps the principal value of my work in Benson is that it has given me pleasure. References Boekhout, T. (1991) A revision of ballistoconidia-forming yeasts and fungi. Studies in Mycology 33: 1-194.
III
Volume 10, Part 3, August 1996 Webster, J. & Chien, C-Y. (1990) Ballistospore discharge. Transactions of the Mycological Society of Japan 31: 301-315. Papers under the sole authorship of CTI as dated:(1928) Spore discharge in Podospora curvula de Bary. Annals of Botany 42: 567-570. (1975) Guide to aquatic hyphomycetes. Scientific Publication No. 30. Freshwater Biological Association, Ambleside. (1978) Spore discharge in Acrospermum. Transactions of the British Mycological Society 70: 287-289. (1981) Flammulina velutipes in relation to freezing and drying. Transactions of the British Mycological Society 76: 150-152. (1982a) Basidiospore germination and conidium development in Auricularia. Transactions of the British Mycological Society 78: 161-166. (1982b) Basidiospore germination and conidium formation in Exidia glandulosa and Tremella mesenterica. Transactions of the British Mycological Society 79: 370-373. (1982c) Basidiospore germination in Tremella foliacea. Transactions of the British Mycological Society 79: 561-563. (1983) Basidiospore germination and conidium development in Dacrymycetales. Transactions of the British Mycological Society 81: 563-571. (1984a) The basidium in Ustilago. Transactions of the British Mycological Society 81: 573-584. (l984b) Myxacium nucleatum and its conidial state. Transactions of the British Mycological Society 82: 358-360. (1984c) . Patterns of ballistospore germination in Tilletiop sis, Auricularia and Tulasnella. Transactions of the British Mycological Society 83: 583-591. (1985) Dicellomyces scirpi: its conidial stage and taxonomic position. Transactions of the British Mycological Society 84: 542-545.
(1986a) Entomophthora pseudococci and its patterns of conidial germination. Transactions of the British Mycological Society 86: 239-245 (1986b) Bensingtonia ciliata gen. et sp. nov., a ballistosporic fungus. Transactions of the British Mycological Society 86: 325-328. (1986c) Hyphal and conidial germination of ascospores in Bulgaria inquinans and of basidiospores in Ditiola pezizijormis. Transactions of the British Mycological Society 87: 143-146. (1987) Germination of teliospores in certain smuts. Transactions of the British Mycological Society 88: 355-363. (1988a) Patterns of basidiospore germination in Platygloea effusa. Transactions of the British Mycological Society 91: 162-166. (1988b) Ballistospores in Melanotaenium endogenum. Transactions of the British Mycological Society 91: 712-714. (1989a) Note on the basidium in Tilletiaceae. Mycological Research 93: 387-389. (1989b) Basidium development in some species of Ustilago. Mycological Research 93: 405-412. (1991a) Liberation of ballistospores in Tilletiopsis. Mycological Research 95: 1393-1394. (1991b) Itersonilia. Mycologist 5: 35-37. (1992a) Conidia in Helicogloea and Saccoblastia in relation to taxonomy. Mycological Research 96: 734-736. (1992b) The conidial stage of Exidiopsis effusa and E. longispora. Mycological Research 96: 932-934. (1992c) Discharge of ballistospores in Tilletiaria anomala. Mycological Research 96: 987-989. (1995a) Blastoconidium production from conjugated basidial cells in Cintractia. Mycological Research 99: 140-142. (1995b) Types of reproductive cell in Exidia recisa and Sirobasidium intermediae. Mycological Research 99: 1187-1190. (1995c) Products of teliospore germination in Tilletia hyalospora. Mycological Research 99: 1247-1248. (1996) Two kinds of ballistoconidia in the anamorph of Tilletia setariae. Mycological Research 100: 173-174.
BRITISH MYCOLOGICAL SOCIETY CENTENARY SYMPOSIA
One of the main components of the BMS Centenary Year was the Triple Symposium Meeting at Sheffield, featuring firstly 'A Century of Mycology' in which several distinguished British and American workers contributed to an authoritative commentary on the present state of mycology and the potential future developments. A second day was devoted to the theme of 'Fungal Biodiversity' and brought together an extensive range of contributors dealing with an enormously varied selection of topics from the microscopic to the global, from the simple to the most highly specialised inter-relationships. Full reports on these symposia and the Postgraduate Symposium which occupied the third day of the meeting will appear in the November issue of the Mycologist.
•
THE INDIAN SUMMER OF A MYCOLOGIST C.T.INGOLD 12 Chiltern Close, Benson, Oxon OX10 6LG
Having retired in 1972 at the age of 67, I was, for the next few years, still much concerned with universities abroad through the Inter-University Council for Higher Education Overseas, with which I had long been associated. During this period, my only contributions to mycology were a 'Guide to Aquatic Hyphomycetes' (1975)* and a note on spore discharge in Acrospermum (1978) which closely mirrored my first paper on fungi (1928). In 1977, having moved to Benson in Oxfordshire, I began to cast around for a mycological project. The Benson Brook, a chalk stream , was a poor source of aquatic hyphomycetes. Further, working at home, I could not match the splendid work on these organisms in train elsewhere. My first move in a new direction came with a passing interest in Flammulina velutipes (Curt.) Karst., then locally abundant on the numerous stumps of elm killed by Ophiostoma ulmi (Buisman) Nannf. In the winter of 1978-79 Benson airfield had its lowest recorded temperature, and basidiomes of F. velutipes were frozen solid. Nevertheless spore liberation resumed as soon as they thawed. This encouraged me to make some simple experiments on the almost unique resistance of this agaric to freezing (1981) and led me to consider other basidiomycetes that shed their spores in the depth of winter. Conspicuous among these were the jelly fungi. In studying these I was soon deflected to a consideration of their microconidial stages which seemed to have been inadequately described. In Dacrymycetaceae the microconidia occur either singly or in clusters, and then it is clear that they are formed in succession side by side (1983). Basidiospores in this family are often described as septate. However, it became clear that, at the moment of liberation, they are always unicellular although thereafter, transverse septa rapidly Footnote * Dates in brackets refer to papers solely in the author's name
form. Indeed, my many observations of a wide range of basidiomycetes suggest that when a ballistospore leaves its sterigma, it is invariably non-septate. I soon became especially interested in Auriculariales, Tremellales and Tulasnellales cultures of which, derived from basidiospores, were either yeast-like as in Tremella spp (1982b, 1982c) or mycelial as in most genera. Frequently their hyphae formed microconidia which were Cshaped in Auricularia spp (1982a), Exidia glandulosa (1982b), Myxarium nucleatum (1984b), Exidiopsis effusa (1992b) , Platyglo ea effusa (1988a) and Dicellomyces scirpi (1985), but globose in Helicogloea lagerheimii (1992a), stellate in Tulasnella cystidiophora (1984c) and bacilliform in Exidia recisa (1995b). The interesting feature of all of these conidia is that they are produced in succession, one behind the other, as in an ascomycete phialide. It appeared that the pattern of germination of liberated basidiospores depended on local conditions (1984c). In all the jelly fungi I have studied, basidiospores on fresh 0.2% malt agar invariably germinated with hyphal germ-tubes, whereas those germinating close to an established parent mycelium tended to produce microconidia immediately. Further, in all species the basidiospores stranded on a parent hymenium mostly germinated by repetition, a process unknown in Dacrymycetaceae. The tendency of spores germinating close to a mycelium of the same species to produce a sporing stage directly is, apparently, a general phenomenom exhibited by such diverse fungi as Conidiobolus spp. (1986a) and Bulgaria inquinans (1986c). The epimycetes on jelly fungi also attracted my attention. From inverted basidiomes of Auricularia auricula-judae Schroet. colonies developed on agar below from spores liberated actively by these surface fungi. As was to be expected, Sporobolomyces spp and, to a lesser degree, Tilletiopsis spp were abundant. Less expected were several species of Conidiobolus
Volume 10, Part 3, August 1996 (1991b). Almost invariably present was Itersonilia perplexans Derf, and this proved of interest especially in relation to the process of spore liberation (summary in 1991b). The fairly large Buller drop in this species takes relatively long (30-50 sec) to grow to full size before the ballistospore suddenly disappears from its sterigma. I watched the whole process on many occasions under high power and for the first time observed the adaxial liquid blob that arises on the side of the spore as the Buller drop is growing. I was able to interest John Webster in this fungus, and work by him and his associates has led to a revealing picture of ballistospore liberation (Webster & Chien, 1990). Among the epimycetes of Jew's Ear I encountered a mirror-image yeast that did not fit a described genus. This was named Bensingtonia ciliata (1986b) in honour of the village in which I live, the original name of which was Bensington. More recently (Boekhout, 1991) five further species of the genus have been recognised. In the mid eighties, having developed a general interest in heterobasidiomycetes, I watched germination of teliospores of Ustilago avenae from Arrhenatherum elatius, and was surprised to note that the lowermost cell of the basidium was often entirely enclosed by the teliospore, so that the basidiospore from it had to emerge through the thick teliospore wall. This encouraged me to germinate the smut spores of several other species of Ustilago. It became clear that there were several different patterns of teliospore germination, but these could nearly always be interpreted as variations on the theme of a 4celled basidium (1984a, 1989b, 1995a). This work on smuts extended and soon was responsible for most of my mycological activity, involving ultimately watching the germination of teliospores in over 50 species spread among 10 genera of Ustilaginaceae and 5 genera of Tilletiaceae. In the past few years I have had a special interest in the form of the basidium in certain tilletiaceous genera namely Tilletia (1987), Urocystis (1987, 1989a) and Melanotaenium (1988b). It seems to me that in Tilletia the basidium is basically a condensed branched structure with a tendency towards dichotomy. This idea had further support from the surprising discovery that in T. hyalospora Massee (now Ingoldiomyces hyalosporus Vanky) (1995c) the basidium has ballistosporic
basidiospores instead of filamentous ones not actively liberated. The basidium in that smut bears one or two spores, and in the two-spored types there is a single dichotomy. I now consider that such a basidium represents the primitive condition in Tilletiaceae. Initially, in my study of smuts, I relied on collections made during daily country walks, but later depended on material sent by friends, and, in the past few years, particularly on the exsiccata of his world-wide collections generously put at my disposal by Dr K. Vanky, In the early nineteen nineties I became interested in the liberation of ballistospores in Tilletiopsis spp and in the similar anamorphs of Tilletia spp and Tilletaria anomala Bandoni & Johri. In all these it could be shown that, although most ballistospores were set free singly, a considerable number sprang from their sterigmata in bundles of 2-6 (1991a, 1992c, 1996). In spite of the somewhat haphazard nature of my mycological studies in Benson, it seems to me that certain contributions to the knowledge of heterobasidiomycetes have been made namely: the elucidation of the nature of microconidia in jelly fungi; the exploration of the epimycetes of Jew's Ear; the recognition of Itersonilia perplexans as a useful tool in the study of ballisto spore liberation; the indication that the pattern of basidiospore germination depends on local conditions; the interpretation of the variations in teliospore germination in Ustilaginaceae in terms of a four-celled basidium; the recognition of the basidium in Tilletia as a branched structure, together with the suggestion that T. hyalospora Massee represents the primitive state in Tilletiaceae; and the observation that in Tilletiopsis ballistospores can be set free in bundles as well as singly. Since 1977 my work has been carried out in a small room at home. It would not have been possible if my old Department, through Jane Nicklin, had not kept me supplied with sterile Petri dishes and agar. Also, I owe a great debt to John Webster who not only helped with photography at his Exeter laboratory, but was also a source of encouragement and helpful criticism. Perhaps the principal value of my work in Benson is that it has given me pleasure. References Boekhout, T. (1991) A revision of ballistoconidia-forming yeasts and fungi. Studies in Mycology 33: 1-194.
III
Volume 10, Part 3, August 1996 Webster, J. & Chien, C-Y. (1990) Ballistospore discharge. Transactions of the Mycological Society of Japan 31: 301-315. Papers under the sole authorship of CTI as dated:(1928) Spore discharge in Podospora curvula de Bary. Annals of Botany 42: 567-570. (1975) Guide to aquatic hyphomycetes. Scientific Publication No. 30. Freshwater Biological Association, Ambleside. (1978) Spore discharge in Acrospermum. Transactions of the British Mycological Society 70: 287-289. (1981) Flammulina velutipes in relation to freezing and drying. Transactions of the British Mycological Society 76: 150-152. (1982a) Basidiospore germination and conidium development in Auricularia. Transactions of the British Mycological Society 78: 161-166. (1982b) Basidiospore germination and conidium formation in Exidia glandulosa and Tremella mesenterica. Transactions of the British Mycological Society 79: 370-373. (1982c) Basidiospore germination in Tremella foliacea. Transactions of the British Mycological Society 79: 561-563. (1983) Basidiospore germination and conidium development in Dacrymycetales. Transactions of the British Mycological Society 81: 563-571. (1984a) The basidium in Ustilago. Transactions of the British Mycological Society 81: 573-584. (l984b) Myxacium nucleatum and its conidial state. Transactions of the British Mycological Society 82: 358-360. (1984c) . Patterns of ballistospore germination in Tilletiop sis, Auricularia and Tulasnella. Transactions of the British Mycological Society 83: 583-591. (1985) Dicellomyces scirpi: its conidial stage and taxonomic position. Transactions of the British Mycological Society 84: 542-545.
(1986a) Entomophthora pseudococci and its patterns of conidial germination. Transactions of the British Mycological Society 86: 239-245 (1986b) Bensingtonia ciliata gen. et sp. nov., a ballistosporic fungus. Transactions of the British Mycological Society 86: 325-328. (1986c) Hyphal and conidial germination of ascospores in Bulgaria inquinans and of basidiospores in Ditiola pezizijormis. Transactions of the British Mycological Society 87: 143-146. (1987) Germination of teliospores in certain smuts. Transactions of the British Mycological Society 88: 355-363. (1988a) Patterns of basidiospore germination in Platygloea effusa. Transactions of the British Mycological Society 91: 162-166. (1988b) Ballistospores in Melanotaenium endogenum. Transactions of the British Mycological Society 91: 712-714. (1989a) Note on the basidium in Tilletiaceae. Mycological Research 93: 387-389. (1989b) Basidium development in some species of Ustilago. Mycological Research 93: 405-412. (1991a) Liberation of ballistospores in Tilletiopsis. Mycological Research 95: 1393-1394. (1991b) Itersonilia. Mycologist 5: 35-37. (1992a) Conidia in Helicogloea and Saccoblastia in relation to taxonomy. Mycological Research 96: 734-736. (1992b) The conidial stage of Exidiopsis effusa and E. longispora. Mycological Research 96: 932-934. (1992c) Discharge of ballistospores in Tilletiaria anomala. Mycological Research 96: 987-989. (1995a) Blastoconidium production from conjugated basidial cells in Cintractia. Mycological Research 99: 140-142. (1995b) Types of reproductive cell in Exidia recisa and Sirobasidium intermediae. Mycological Research 99: 1187-1190. (1995c) Products of teliospore germination in Tilletia hyalospora. Mycological Research 99: 1247-1248. (1996) Two kinds of ballistoconidia in the anamorph of Tilletia setariae. Mycological Research 100: 173-174.
BRITISH MYCOLOGICAL SOCIETY CENTENARY SYMPOSIA
One of the main components of the BMS Centenary Year was the Triple Symposium Meeting at Sheffield, featuring firstly 'A Century of Mycology' in which several distinguished British and American workers contributed to an authoritative commentary on the present state of mycology and the potential future developments. A second day was devoted to the theme of 'Fungal Biodiversity' and brought together an extensive range of contributors dealing with an enormously varied selection of topics from the microscopic to the global, from the simple to the most highly specialised inter-relationships. Full reports on these symposia and the Postgraduate Symposium which occupied the third day of the meeting will appear in the November issue of the Mycologist.
•