In memoriam: Walter Gams (1934–2017)

ABSTRACT

Prof. Dr. Walter Gams, an internationally famous taxonomist, died on 9 April 2017 in Bomarzo, Italy. He spent his career at the Centraalbureau voor Schimmelcultures (CBS) in the Netherlands. Walter specialized in the taxonomy and nomenclature of fungi, in particular little-differentiated hyphomycetes, and was considered the world authority on the identification of soil fungi. He was influential in shaping the rules for fungal nomenclature for several decades. He was presented with the Distinguished Mycologist Award of the Mycological Society of America in 2005. Walter was an all round naturalist and teacher, and an avid amateur musician and patron of the arts. He travelled widely and had friends all over the world, who miss his hospitality and generous spirit.

Significant works by this author:

10.1080/00275514.1999.12061016

10.1080/00275514.1983.12023783

10.1080/00275514.1998.12026984

10.1080/00275514.1995.12026545

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Fusarium miscanthi sp. nov. from Miscanthus litter

Phialemonium, A New Anamorph Genus Intermediate Between Phialophora and Acremonium

Konrad Walter Gams (FIG. 1), known to all as Walter (he disliked his first name, or even to be reminded of it by the initial), was born on 9 August 1934 in Zürich, Switzerland, to Margarete Gams-Schima and Helmut Gams, a professor at the University of Munich, Germany, and later the University of Innsbruck, Austria. After undergraduate studies at the University of Innsbruck, Walter returned to Zürich and studied for 1 year with his uncle, Emil Schmid. He earned his PhD at the University of Innsbruck in 1960, followed by a year with an Austrian scholarship studying with the famous soil microbiologist and ecologist, Dennis Parkinson, at the University of Liverpool, UK. For his first job, Walter was hired by K. H. Domsch to study fungi in agricultural soils at the Biologische Bundesanstalt, Kiel-Kitzeberg, Germany, where he worked from 1961 to 1967. He then spent the rest of his career at the Centraalbureau voor Schimmelcultures (CBS; now Westerdijk Fungal Biodiversity Institute), first in Baarn and then later in Utrecht, the Netherlands. He married Sophia Aaltine Luinge in 1972, and they had two daughters, Hedi and Hilde; later, he became a devoted grandfather to Mingxia and Shuai. Walter was an honorary member of British Mycological Society, Iranian Mycological Society, and Mycological Society of America. In 2005, he was presented with the Distinguished Mycologist Award of the Mycological Society of America, and in 2012 the Anton de Bary medal of the Deutschen Phytomedizinischen Gesellschaft. He retired in 1999 but remained associated with the institute for another decade before retiring permanently and dividing his time between the Netherlands and renovating an apartment he had bought in a hilltop castle in Italy. Walter authored over 300 publications, including six books, proposing one new order, 10 new families, 57 generic names, and 622 species epithets. Three genera and 39 species were named in his honor by his colleagues (Kuyper and Gutter 2017).

Figure 1. A. Walter Gams, ca. 1980 (photo: Gams family). B. In his office at CBS in Utrecht, 2002 (photo: R. Zare).

RESEARCH

Walter was widely regarded internationally as the world’s expert on the taxonomy of soil fungi, in particular what he called “little-differentiated” microfungi. Initially, he focused on Mortierella, a difficult genus then considered part of the Zygomycetes, in some cases manifesting as little more than a pale thin stalk with a head of a few sporangiospores (Gams 1976, 1977). Subsequently, he became renowned for his expertise in the taxonomy of hyphomycetes, in particular Acremonium, a name he rescued from obscurity to replace the confused but widely used name Cephalosporium, as well as Verticillium. These two genera, like Mortierella, have very reduced morphology. Both of them were difficult and speciose groups, with characters often preserved poorly in type specimens, and the material was so inconspicuous as to be almost impossible to locate with a dissecting microscope. Culturing these species and comparing in vitro morphology with what was seen in situ was essential. In those days before digital photography, Walter used a drawing tube to make pencil sketches of everything that he studied at a standard magnification of 2000× (FIG. 2). This technique allowed side-by-side comparison of observations made decades apart over his long career. He taught his students and colleagues this method of note-keeping, with the maxim that “You don’t understand a fungus until you draw it.”

Figure 2. The original pencil drawing by Walter Gams of the type strain for the fungus eventually described as Tolypocladium inflatum, the source of the life-saving immunosuppressant drug cyclosporine.

One of his most famous works is his monograph “Cephalosporium-artige Schimmelpilze (Hyphomycetes)” (Gams 1971b). Written in German and printed on thin paper in a small font, the book was a challenge for other taxonomists and students to use. No one could accuse Walter of extravagance in his illustrations or descriptions, which were often as minimal as the morphology of the fungi he studied. His papers were agonizingly precise, and one sometimes had to read and interpret them (whatever their language), almost as if they had been “zipped” by a computer and needed to be unzipped in the reader’s mind before use. Walter was aware of these difficulties and later updated and partly translated the Cephalosporium book into English to be used as a manual for a teaching workshop in Japan, a version that was widely circulated but not formally published.

The morphological hiatus between the unbranched Acremonium and the whorled branching of Verticillium was never unambiguous, and there are many intermediates. Some of the species in what Walter called “Verticillium subgenus Prostrata” were included in the Cephalosporium book, but unraveling the species in this group and a few others of similar difficulty, such as Monocillium/Niesslia (Gams et al. 2019), occupied his attention for the rest of his life. First, he worked on a series of species that caused serious problems in mushroom farms (Gams and Van Zaayen 1982). In 1998, still the early days of DNA-based taxonomy in fungi, he started working with one of the coauthors of this memorial, Rasoul Zare, who was completing his PhD with Paul Bridge at the CAB International Mycological Institute in Egham, UK, a collaboration that continued for almost 20 years. Together, they refocused Walter’s extensive knowledge derived from microscopic study of living cultures through the lens of rDNA sequencing. The resulting papers, compiled in a book (Zare and Gams 2004), extended the number of known species, distributed them among several genera, and contributed to a growing realization that the phylogenetic breadth of these simple organisms was much broader than had been realized.

The range of fungi classified in Acremonium and Verticillium led Walter to other important hyphomycetes that expressed a bit more phenotypic variation, and he made contributions to the taxonomy of Fusarium (which has microconidia very much like Acremonium; e.g., Waalwijk et al. 1996; Gams et al. 1999), Gliocladium (Schroers et al. 1999), and Trichoderma (Samuels et al. 2002; Gams and Meyer 1998). Walter worked with the Swiss pharmaceutical company Sandoz on a slow-growing fungus they had isolated from soil in Austria (FIG. 2), describing the new genus Tolypocladium (Gams 1971a). This was the source of the immunosuppressant drug cyclosporin A (or cyclosporine), which prevents tissue rejection during human organ transplants. This drug is estimated to have saved the lives of half a million people since its introduction for clinical use in 1983, not to mention having yielded annual profits of about $1 billion/year for the companies that produce it. It is unusual for a taxonomist to have been a critical part of such an important discovery that benefited so many people.

With his colleague Klaus Domsch, Walter published his first book, Pilze aus Agrarböden (Domsch and Gams 1970), later modified into an English version called Fungi in Agricultural Soils (Domsch and Gams 1972). Within a decade, this was transformed into the Compendium of Soil Fungi (Domsch et al. 1980; a new edition with updated taxonomy published in 2007) and quickly became the essential reference work for all ecological work on soil fungi. Combining identification keys, capsule descriptions, and concise literature reviews cribbed by Walter from the multitude of index cards and stacks of fan-fold computerized literature searches that overflowed his office, this book was a kind of Wikipedia resource long before that concept was common.

Walter’s involvement with the monumental The Genera of Hyphomycetes (Seifert et al. 2011) started when Keith was a student in Baarn. They shared the notes and additions they had written into their copies of the first edition by Carmichael et al. (1980). Sent by mail for safety’s sake, Keith’s heavily annotated copy disappeared when he returned to Canada; the post office delivered an empty envelope and an apology. A lifelong reader and compiler of mycological and botanical literature, with a prodigious memory, Walter had initiated literature lists for a different project on hyphomycete genera originally planned by S. J. Hughes, G. L. Hennebert, C. V. Subramanian, B. C. Sutton, and K. Tubaki. He also had notes and drawings on all the fungi that had crossed his desk from his own collecting and from his work for the CBS identification service. This wealth of information was integrated into the “dictionary” of the original Carmichael et al. (1980) book, derived from the original computer files provided by Lynne Sigler, amended with Keith’s similar body of notes, and became the nucleus for the 2011 book. Walter’s sharp copyeditor’s eye, and obsession with consistency for the final details, further enhanced the end result.

Walter initiated the removal of selected species from his large beloved genera Acremonium and Verticillium based on differences in teleomorph relationships or an intuitive emphasis of what he considered atypical morphological characters. The removal of what he considered as disparate elements into new or resurrected genera, such as Gibellulopsis (Zare et al. 2007), Phaeoacremonium (Crous et al. 1996), Lecythophora and Phialemonium (Gams and McGinnis 1983), and Plectosporium (Palm et al. 1995), presaged the much more dramatic dismemberment of these genera that was to follow (Summerbell et al. 2011, and subsequent papers by several authors). Although he appreciated the power of DNA-based phylogenetics, the last phase in Walter’s career was challenging. After decades applying a conservative taxonomic philosophy, he had difficulty agreeing with the necessity of dividing anamorph genera to correlate with phylogeny; he was a strong advocate for accepting paraphyletic anamorph genera. The rationalization of dual nomenclature, that one could have a “natural classification” of anamorphs and a parallel classification of teleomorphs, was deeply imbedded in many of us. But it was contrary to his training, where anamorph genera were form genera, and his personal taxonomic approach as a lumper of genera but a splitter of species. It was not until the fall of dual nomenclature in 2011 that Walter accepted the inevitability that the fungi that he had spent his life studying would be divided into much smaller monophyletic genera. Despite his discomfort with that process and its results, the young mycologists around Walter remained highly appreciative of his deep knowledge. The stability of the resulting nomenclature and taxonomy seems to be in sight and will owe an immense debt to the rationality and order that Walter brought to these inconspicuous microfungi when he removed them from the chaos of classical taxonomy with his morphological and cultural studies.

TEACHING

For most of Walter’s career, CBS was located in a white, stuccoed, rectangular, two-story building in a residential area of the quiet Dutch town of Baarn, sharing a backyard and a teaching laboratory with the renowned Willie Commelin Scholten (WCS), a phytopathology laboratory operated by several Dutch universities. The CBS culture collection then occupied much of the ground floor, with shelves filled with racks of agar slants and cabinets of lyophils, and in the basement were the liquid nitrogen tanks, scanning electron microscope, and chemistry laboratories. Most of the scientists were on the second floor, with offices that doubled as small laboratories on both sides of the central hallway. Walter’s office looked out over the lawns toward the WCS greenhouse and was stuffed full of cabinets of filing cards, the shelves crammed with books from his personal library and his ever-expanding set of A5 binders filled with his notes, and the laboratory bench covered with dried agar in Petri dishes, slants, and microscope slides. Being remote from university campuses, Baarn was a challenging home base for anyone trying to attract students wishing to study mycology. A cross-appointment helped to solve this problem. In addition to his full-time appointment at CBS, Walter received his Habilitation from the R. W. Technische Hochschule in Germany in 1972, enabling him to become a lecturer at the University of Aachen. He then had a continuous stream of undergraduate students from Aachen and from Dutch universities who did research projects with him as part of their diploma work. The teaching classroom, under the library at one end of the building, quickly filled up with hundreds of agar slants of soil fungi as the students’ isolates were sorted by colony characters into test tube racks, to be identified to species level using the Compendium. We all pitied these students, who had been thrown into a deep pool and who had to swim diligently to meet Walter’s exacting standards. Nevertheless, there are several names that appear in the scientific literature only once, as coauthors on papers by Walter. These students then moved on to be doctors, lawyers, or farmers, all the richer for having learned critical scientific reasoning from their mentor.

Although the work of CBS was primarily research, Walter and his CBS colleagues instituted the 4-week “summer course,” a rigorous, old-fashioned introduction to taxonomic mycology but with the modern twist that all the fungi were grown in pure culture for the students to study. The textbook, largely written by Walter (Gams et al. 1975ff), is a miracle of minimalism, distilling taxonomic mycology into about 100 pages, including a detailed methods section and references. For those of us lucky enough to still have a copy, it remains an invaluable text to jog the memory for details or be reminded of fundamental methodologies. Although at first intended as a summer course for undergraduates, the absence of anything similar in European universities meant that the course was attended by nascent mycologists from all over the continent. It served as the inspiration for several courses taught annually at the Westerdijk, now updated for the molecular age without losing track of the field biology, culture isolation, and micromorphological skills that gave these courses their initial relevance (Crous et al. 2019). Knowing that many potential students could not afford the course, Walter established a scholarship program. Similarly, with the aim of supporting scientific research by young biologists, he later founded the nonprofit foundation “Research in mycological taxonomy and ecology” (Studienstiftung mykologische Systematik und Ökologie) in 1995, now to be administered by the German Mycological Society (Stadler and Schroers 2019).

Walter was a generous host for all who visited CBS in Baarn. For students, the weekends away from home were a chance to explore tourist and natural sites around the Netherlands. Many were permanently psychologically scarred by their experiences as passengers in Walter’s car as he raced along at 80 km/h on the narrow, winding roads atop the dikes through the polders, scanning the sky for interesting birds. Having learned to drive on the Autobahn, Walter had driving habits that disturbed his nail-biting passengers throughout his life, although thankfully there were no serious consequences. After a snowfall, as someone raised in the Alps, he instantly became one of the Netherlands’ most skilled drivers and railed gleefully at the floundering of the other motorists. After only a few years in Baarn, he became known to the residents as “The Austrian,” not for his science, but because whenever it snowed he cross-country-skied along the bicycle paths to get to work. This was rare enough to be a memorably esoteric sight in this small provincial town.

For decades, the Gams-Luinge home was the gathering point for mycologists who visited CBS. During these evenings, guests engaged in intense discussions about fungal taxonomy that bored Sophia and their daughters to tears. Often, there were mycologists visiting from several countries at once and discussions would proceed with Walter in the middle, conversing in a different language with each person in the room; he spoke six languages fluently. Walter, especially in his later years, was a man of extremely few words, and it was usually very difficult to stimulate a self-perpetuating conversation; often you received one word or telegraphic reactions such as raised eyebrows or an embarrassed grin in response to what you thought were generous leading questions. There were often long silences. After supper and casual conversations were exhausted, it was often simpler to sit through the interminable slide shows of Walter’s latest travels, a situation that was only exacerbated with the invention of digital photography and the elimination of the expense of developing film.

OTHER ACTIVITIES

Walter grew up in the shadow of his illustrious father, the author of a series of German language field guides to “nonvascular plants” (mosses and lichens) known as Kleine Kryptogamenflora. With this influence, Walter studied botany in his early years and became an expert on the vascular and nonvascular floras of Europe, extending his knowledge to other continents as he traveled. The coauthors of this article have been in the field with Walter on four continents, and he is the most complete naturalist we have ever known. We were always astonished at the breadth of his knowledge of the flora and fauna no matter where he was. These excursions were peppered with the inevitable questions “Do you know what this is? What is this related to?” not because he didn’t know, but because he wanted to know whether we knew. He was a core member of the Nederlandse Mycologische Vereniging (Dutch Mycological Society), one of the most advanced amateur mycological societies in the world, sought for his broad field knowledge of all kinds of macro- and microfungi (including rusts and smuts) and his comprehensive knowledge of vascular and nonvascular plants.

With his broad taxonomic knowledge, Walter naturally rose to prominence within the International Association of Plant Taxonomy’s “Special Committee on Fungi and Lichens” (now Nomenclatural Committee for Fungi). Relatively quickly after he joined the committee in 1984, he was appointed to the chair and served from 1991 to 2005. He was absorbed into the complexities of fungal nomenclature during discussions on the sanctioning of names at the 1981 Botanical Congress in Sydney, Australia. When dual nomenclature began to be challenged in the mid-1980s, Walter engaged in intricate and far-reaching discussions over revisions of tenets of Article 59, which governed the naming of pleomorphic fungi. When the One Fungus, One Name movement crystallized under the banner of the Amsterdam Declaration in 2011, Walter emerged as a passionate defender of dual nomenclature, arguing that its abandonment would cast the taxonomy and nomenclatural history of anamorphic fungi into the abyss. With the eventual implementation of the single-name system in 2012, Walter joined the discussions over the adjustments to a unified single-named taxonomic system, participating in working groups and coauthoring position papers focused on specific fungal groups.

Walter was a rigorous editor, and his skills were applied as a member of the editorial boards of Allionia, Cryptogamie-Mycologie, Mycologia Austriaca, Nova Hedwigia, Phytopathologia Mediterranea, Studies in Mycology, and Zeitschrift für Mykologie. The CBS publication policy required internal review of all manuscripts before submission. Richard and Keith have the traumatic memory of asking Walter to review an early manuscript, only to have it returned covered with so many comments, corrections, and criticisms in several languages and different colors of ink that the underlying manuscript could hardly be read. The fungus was in the wrong genus, the description was full of “banalities,” the published monograph that we had cited extensively was full of mistakes and inaccuracies, with the final summary that our manuscript was “SLORDIG!” (Dutch for sloppy). We had received an intense education in how to write a taxonomic paper.

As a linguist, Walter was also a Latin scholar, and one of a handful of mycologists able to express genuine scorn and indignation over the quality of the published Latin descriptions then required for valid proposals of new taxa. He was happy to craft Latin diagnoses for others and preferred that they just give him an English text to translate, rather than butchering the language by attempting a preliminary draft on their own. He was just as acute in Greek: when Keith and Richard came to him with an epithet meaning “beach” and based on the word ακτή (akte), he pointed out that the conflicting word ἀκτή (promontory) also existed and recommended using παραλία (paralia) instead. Not only did this work in nomenclature, but it also served Richard well when, years later, he had to find his way to the beach at Rhodes following Greek signs.

Microcomputers entered the day-to-day life of scientists and were pressed into service in the management of biological collections in the early 1980s. Walter embraced them and in the early days was often perched possessively in front of the only microcomputer in the institute, typing on the word processor as if he were playing a musical instrument. The Internet was hardly a dream then, yet Walter lobbied to transfer the volumes of paper into a digital form, entering much of the raw data associated with the world’s largest culture collection himself during the initial stages. There was some concern in the institute that Walter was disappearing into the computer (something many of us can now relate to), and he did not publish much research for several years.

Walter and Sophia, who taught music and played the recorder in chamber music groups, were known in the Baarn community for their passion for classical and folk music and the visual arts. Walter played the virginal, adopting the same rigid posture and intensity with which he approached the word processor. When he attended a recital, he brought the score and read along as the musicians proceeded through the pieces, shaking his head if he detected a minor error of timing or intonation. He greatly preferred Bach and other “oude muziek” but could enjoy an opera by Alban Berg or the music of a traditional Iranian ensemble. The Gams-Luinge house was decorated with modern art created by Sophia herself, other family members, and diverse artists who Walter supported as a patron. Prominent among the latter was Stephanie Morin, the mother of Walter’s godson Justin Alexander Korovkin and partner of his anthropologist-poet friend Michael Korovkin.

POST RETIREMENT

When he retired, Walter bought a two-story flat from his colleague Silvano Onofri in the medieval Palazzo Orsini in Bomarzo, Italy, and proceeded to divide his time between the Netherlands and Italy, stopping to check in on his mother in Austria on the way. His friends and colleagues, who were invited persistently until they agreed, were hosted with great panache, lounging on the stone balcony that opened out over the airy valley below, admiring the lichens on the terracotta tiles of the ancient roof. Bomarzo is famous for its Parco dei Mostri (Park of Monsters), which Walter considered far too low-vulgar for any of his guests, preferring instead to tour them through the ruins of the Etruscan civilization in the arid surroundings of Tuscany.

Walter traveled widely, attending most of the International Mycological and Botanical Congresses, a few Mycological Society of America (MSA) conferences, and visiting his friends in Australia, Canada, and Japan, collecting wherever he went in the more innocent times preceding the Convention on Biological Diversity. Despite the troubled international climate, he traveled six times to Iran between 2001 and 2016. He coaxed Richard, who was suffering last-minute visa problems, to travel to the Asian Mycological Congress in Karaj, Iran, co-organized by Rasoul. The conference was just a few days after the 9-11 attack in New York, and nearly all non-Iranians canceled their fights, but Walter insisted, “we cannot let Rasoul down.” It turned out to be a wonderful experience. His friendship knew no borders, and he continued to engage young people whenever he had a chance, including Hossein, Rasoul’s 2-year-old nephew.

Walter was essentially fearless and did not seem to worry about adverse consequences for behavior that sensible people would avoid. He loved food, especially nuts and fresh sweet tropical and temperate fruits such as grapes and melons. While walking through rural Japan awaiting his flight home from the 3rd International Mycological Congress (IMC3), he espied a tree bursting with ripe figs and scrambled over the fence to pick some. The woman of the house chased him and Keith from the yard waving a broom and shouting in angry Japanese. In Bomarzo, Walter always had fresh collection of what he called “post-harvest” walnuts and hazelnuts, which were in fact “pre-harvested” before the owners could pick them. Rasoul noticed one day, after their plastic bags were nearly filled, that Walter had disappeared in the bushes and realized he had better do the same with the sound of the farmer’s tractor chugging closer. Apparently safe, they continued picking, to be challenged by a pack of furiously barking dogs, which Walter ignored until they lost interest and wandered off.

When he was younger, Walter loved skiing, riding motorcycles, bush-walking, and climbing in the mountains. Knee replacement surgery eventually slowed him down a bit, but not completely. We used to accompany Walter into the Dutch canals in collapsible canvas kayaks, which rocked perilously in the wakes of passing houseboats and motorboats. Walter would drive into the opaque sludge of the canal to cool himself off; he would swim in anything that vaguely resembled water, and always emerged refreshed and reinvigorated.

At the 10th International Mycological Congress in Bangkok, Thailand, we organized a conference symposium in honor of his 80th birthday. The three of us were speakers that afternoon, along with several other colleagues who had collaborated with Walter through the years. Afterward, with help of the congress chair and Gams collaborator Jennifer Luangsa-ard, we went for an evening dinner buffet boat cruise on the Chaophraya River, transported from the congress center to the dock by a fleet of taxi vans playing tag team to force their way through the stagnant Bangkok traffic. More than 80 people attended, signing a huge birthday banner as we floated past the spectacular Wat Arun Temple on the riverbank. His expression was an inscrutable mixture of joy and embarrassment when a not-so-young Thai karaoke singer put her arm around him to belt out Happy Birthday.

Walter remained active in mycology until the last days of his life. His old-fashioned Germanic formality hid neither his passion for fungi nor his affection for his friends, all of whom have memories of his protracted bear hugs. When he was nominated for the MSA Distinguished Mycologist Award, one nominator described him as “ … a mycological institute on his own.”

Our final correspondence with him was the receipt of a pdf file of what was to be the last paper published while he was alive (Gams 2017), as he was planning his seventh trip to Iran. Walter passed away on 9 April 2017, suffering a severe heart attack as he walked up the stairs of his beloved castle in Bomarzo, Italy. It is difficult to lose such a great friend. Mycology has lost a great spirit.

ACKNOWLEDGMENTS

We are grateful to Walter’s family, Sophia Luinge and Hedi and Hilde Gams, for sharing their memories and photographs with us. After much effort by our colleagues Hans-Josef Schroers and Tom Gräfenhan and Walter’s family, his library has been transferred to Rasoul Zare’s institute in Iran. Walter’s 35 volumes of notes remain in our hands, awaiting a plan that will allow them to be digitized efficiently and made available to future researchers.