PERSOONIA
Published by the Rijksherbarium, Leiden
Volume Part 6, 4, pp. 445-449 (1972)
Taxonomy of operculate discomycetes:
Synthesis
Richard+P. Korf
Plant Pathology Herbarium, Cornell University, Ithaca, New York
A consideration is general given on various aspects of the taxonomy of
is the rather than Operculate Discomycetes. The thesis advanced that genus,
the the More species, may represent basic evolutionary unit. detailed
considerations are devoted to a few topics, for instance to the systematic
of the and position genera Cyttaria Medeolaria.
is accident that here this International It no at First Mycological Congress a
special session on Taxonomy of Operculate Discomycetes should be convened, for
the time was ripe. As you have already heard today, there are a large number of
active workers themselves the of in this seriously applying to problems taxonomy
most intriguing group of fungi.
the strides forward in of Nevertheless, great taxonomy Operculate Discomycetes
be traced in all the brilliant of the can back, nearly instances, to analyses cup fungi
by three mycologists publishing a century ago: the great French master, fimile
Boudier, the brilliant Swiss mycologist Leopold Fuckel, and the Scandinavian giant,
P. A. Karsten. All three possessed not only the ability to discern species, a quality
of all great mycologists, but had in addition that rare gift of rearranging the pieces
of the classification puzzle to provide a giving an insight into relationships. That
of the that have fallen the have some genera they proposed by wayside, or proven
to be polyphyletic in the ensuing century, should in no way diminish our admiration for their often decades ability to recognize affinities, or even a century ahead of their time.
As taxonomists we are usually prepared to utilize any data, fromwhatever source,
which will - the of help us to separate groups process analysis so essential in recog-
for that will in into nizing species, example —or, conversely, help us uniting taxa higher categories, genera, tribes, families, orders—the process of synthesis. We who
concerned with the are actively Operculate Discomycetes are at that fortunate moment in time when several distinct have to focus the disciplines come upon same materials, as some of our speakers today have already pointed out. The thrust ofmy comments today is that, without disparaging the importance of analysis and the importance of discerning species and infraspecific taxa, our real business of the moment is synthesis.
I know that I for all of the of this session in that speak panel voicing our regret
* Paper read at the Symposium "Taxonomy of Operculate Discomycetes" held at the First
International Mycological Congress, Exeter, 1971.
445 Persoonia Part 446 Vol. 6, 4, 1972
Mme Le Gal was unable, by reason of her health, to attend and participate today.
For her studies, detailed and precise, have formed for all of us a solid foundation
which ideas of classification. The and of the families upon to test our genera many
which she has adopted, for which she would be the first to acknowledge her debt to
the work of all delimited classical pioneering Boudier, were by morpho-taxonomic
procedures. In the 25 years since she published her arrangement in the "Recherches
Ornementations des few sur les Sporales Discomycetes Opercules" only a groups
have and these the which she seen significant changes, were very groups recognized
needed critical study. But in those 25 years new tools have been brought to bear, particularly:
1) critical microanatomical study of the apothecium, advocated by Starback,
von Hohnel, and above all by Professor Nannfeldt,
2) cultural studies such as those outlined today by Professor Paden, and a few
another session this Professor days ago at at congress by Hennebert,
studies of nuclear numbers in and cells of the 3) ascospores, paraphyses, vege-
tative mycelium, provided us most recently by Professor Berthet,
4) ontogenetic studies of ascocarp development, quiescent since the initial studies
but have noted in the Dr. Brummelenand by Corner, as you today papers by van
by Professor Kimbrough, attaining new importance in the Ascobolaceae and
Theleboleae,
interest of and 5) ascus wall characters, a current area of several investigators,
6) chemotaxonomic and physiotaxonomic studies of various sorts, including the
blueing reaction of certain asci in Melzer's Reagent and Dr. Arpin's critical analysis of carotenoid pigments in our group.
least is that the accumulation of the What is really impressive, at to me, data,
admittedly by no means complete, has in almost all instances reinforced the Boudier-
Le Gal classification of Operculate Discomycetes. Each independent discipline,
delimited traditional potentially capable of telling us that our groups by morpho-
fictions of instead has logical procedures are or arrays artificially arranged taxa,
pointed to real biological relationships at the generic and higher levels.
This is not to say there are no longer problems for us to consider! We have not
classification that of so perfected our we can now proceed merely to a catalogue
within each and for search for is the the species genus, a infraspecific variants, as
with of But mind have case some our phanerogamic colleagues. to my we reached,
classification which in the Pezizales, a point of validity in our allows us to recognize families and infrafamilial that sound. As facts groups are biologically new emerge,
I feel it is safe to predict that the general outline of our classification will remain unchanged.
dis- Though some of the many problems which confront us have already been cussed the in this let indicate of the today by participants program, me briefly some areas that seem to me to call for critical work.
First and foremost, the microanatomy of the apothecium still needs intensive
Too study in most of the genera of Operculate Discomycetes. few species have been R. P. Korf: On the taxonomy of Operculate Discomycetes 447
critically examined for us yet to base our classification on what may be very useful
anatomical details of taxonomic importance at the generic and higher levels.
I remain staunch advocate ofthe Though a monographic approach to taxonomy,
that critical for I am also convinced species analysis is, at times, not as a necessity
advancement is the of and the of our knowledge as understanding genera, tribes, even
families. Too long, to my mind, has the concept of the species as the basic unit of
and the evolution gone unchallenged. I am convinced from my own studies, from
1 work of others on various ofplants and animals that the basic evolutionary groups ,
unit be of in some cases as subgenera, or may groups species, recognized genera, of Natural mind the even groups genera. selection, unquestionably to my major
well affect of it does individual evolutionary factor, may as groups species as species. their Because real genera are physiologically related, through evolutionary ancestry,
evolve in direction another in many attributes, they may simultaneously one or
under the stress of a particular natural selection pressure. We need not assume in
evolves but the classical way that a single species to form a new species or genus,
rather take broader that related and may a view, species simultaneously respond
change with time. It is for this reason that I advocate intensive study of what con-
characters. Such characters stitute generic, as opposed to specific, cannot, therefore,
be arbitrarily chosen, but must reflect phylogeny. Species, when aggregated into
genera on the basis of phylogenetic similarity, begin to make a valid classification.
Our Professor Clearly, we must avoid excessive generic splitting. colleague,
wrote ofhis real that there to be Berthet, recently me very concern seems a tendency, for at least in the Sarcoscyphineae, to recognize a separate genus nearly every
I admit that I share his For how with species. must concern. many genera one or a
few species can we tolerate with, say, a Conoplea imperfect state? We know it in
Urnula in and in and I unlike Professor that in , Plectania, Korfiella, suspect, Paden,
time we shall find a species of Pseudoplectania that also yields a Conoplea imperfect state. Have we not gone too far in recognizing so many genera of similar Discomy-
when would suffice? cetes perhaps one, Urnula,
it fair that there is rather Though seems to state general agreement today on
generic limits in the Pezizales, clearly there are points of real disagreement. For
taxonomists ourselves the of example, as we disagree among on generic limits the Discina-Neogyromitra-Maublancomyces-Paradiscina-Gyromitra-Pseudorhizina complex of
genera. To the non-specialist on Discomycetes, our taxonomic indecision in this area
that these must seem incredible, compounded by the fact are large fungi, not infre-
quently collected, and for which names are therefore actively sought in our books and papers.
In 1970 I proposed the tribe Boedijnopezizeae within the Sarcoscyphaceae,
1 The that I that the the basic thesis am advancing here, genus may represent evolutionary
in I thank Mr. Paul the unit, not wholly new. my student, Powell, for calling to my attention
selection in carabid recent paper by Darlington ( 1971 ) on group beetles, a beautifully executed case in point. Persoonia Vol. Part 448 6, 4, 1972
based on three genera, Boedijnopeziza, Cookeina and Microstoma, differing from all other members of the Pezizales in having their asci maturing simultaneously within
the apothecium. In all other genera of the order—and in my recent classification
—asci that is asci (Korf, 1972) I recognized over 90 genera mature seriatim, to say, of various and of will be in I know of ages states maturity present any mount. only
one other case of simultaneous ascus maturation among Discomycete-like fungi.
This is in the genus Cyttaria, the type and only genus of the Cyttariaceae, a family
shunted about from Pyrenomycetes to Operculate Discomycetes to Inoperculate
Discomycetes in various classifications. This peculiar genus is found only parasitic
the southern beeches of the It on hemisphere genus Nothofagus. produces large,
in clusters swollen spherical or pyriform ascostromata, usually on a canker of a branch or trunk. Each ascostroma produces 20 to 100 or more large cavities lined
at with a hymenium. In the species I have studied, these asci are all the identical
but each will be its stage of development in any one apothecial cavity, cavity at
The is thus but own developmental stage. ascostroma not an apothecium, a com-
pound structure bearing individualapothecia. The asci are cylindrical, flattened at
the apex, which is thickened in youth and provided with a broad apical ring which, in some species, turns blue in Melzer's Reagent. The ring is sufficiently large that it that in of rather than the recalls seen many species Peziza, tiny blueing pore seen in Helotiales. The thin, flattened sometimes the many apex ruptures, giving appea- such rance of an operculum, but whether one should call asci operculate or inoper-
least for unanswered The of culate remains, at me, an question. ascospores Cyttaria recall in theirform those ofthe Pezizales rather than of the Helotiales. But pycnidia, perhaps better thought of as spermagonia, are found in young ascostromata of at
and member of the Pezizales is known least some species of Cyttaria, no to produce either the simultaneous maturation pycnidia or spermagonia. Despite ascus recalling that in the Boedijnopezizeae, I think it best to treat the Cyttariaceae as a separate order, Cyttariales, and to place it in the Inoperculatae, probably representing a line of development quite unrelated to the Helotiales, Phacidiales, or Ostropales, and not too divergent from the Pezizales.
which I would also call your attention to another anomalous fungus appears to
This is the have affinities with the Operculate Discomycetes. monotypic genus
Medeolaria, described by that master discerner of the odd fungus, Roland Thaxter, almost exactly 50 years ago. It occurs on the stems of a small, North American,
the Medeola where it fusiform herbaceous wild plant in woods, virginiana, causes
shortened internode. these swollen the swellings and a Through areas previously
internal in of completely hyphae emerge a palisade paraphysis-like elements, among which eventually are formed asci with 8 huge, brown ascospores, flattened
ribbed in the best of on one side and longitudinally as Phillipsia or Wynnea. To my
the collected until last when former knowledge, fungus was never again year, a student, Dr. Donald H. Pfister, and I made a special trip to search for it in one of
Thaxter in hours three areas where had reported it. After searching vain for six
thousands Medeola able to find several diseased among of plants, we luckily were R. P. Korf: On the taxonomy of Operculate Discomycetes 449
plants bearing the Medeolaria in various states of development. We are, however,
scarcely any closer to a knowledge of the life history of this peculiar parasite than we
were before, and our hope of studying the asci and their dehiscence mechanism was
frustrated by the discovery that they disappear very early in development. The
those of the large, inequilateral, ribbed asospores recall, among Ascomycetes, only
the and structure of the little Sarcoscyphineae, yet parasitism simple ascocarp more
than felt of asci and lead that Medeolaria deserves a paraphyses, me to propose not
ofwhich it is the sole only a separate family, but a new order, Medeolariales, repre-
sentative. Needless to say, I hope that some of my colleagues here will take up the
study of Thaxter's fungus, to prove its relationships and to determine whether I am
it close the Pezizales its justified in assigning a position to despite evanescent asci,
for which no operculum has been demonstrated.
the order Tubera- Lack ofan operculum is all that has kept us today fromtreating
another that les in our discussions, for here is group very clearly represents probably
the closest relatives to the Pezizales that we know. Loss of a functional operculum
is surely to be expected when an Operculate Discomycete takes to an underground
life and of its other than air The to dispersal ascospores by some means dispersal.
selection pressures to retain the complex apical mechanism of the operculum,
the affects such when operating on all members of Pezizales, no longer a fungus its
have suitable of other the lack of spores a means dispersal by some agent. Despite an
operculum, those of us who work with Operculate Discomycetes are content to
Tuberales the include the among Operculates!
In let that it is fortune to be in the of summary, me note our good working area
Operculate Discomycetes. Our genera appear, for the most part, to be sound. Our
several taxonomic also to have basis in groupsofgenera, at levels, appear a phylogeny.
The refine to the challenges to us are to our system, apply new techniques as they
- - but also appear the scanning electron microscope being a current example to
the detailed of all of that proceed with study our taxa to ensure they are biologically
defensible.
REFERENCES
DARLINGTON, P. J., JR. (1971). Interconnected patterns of biogeography and evolution. In
Proc. nat. Acad. Sci., USA 68: 1254-1258.
R. P. the the In KORF, (1972). Synoptic key to genera of Pezizales. Mycologia 64: (in press).