Title: The simple holocarpic biflagellate Phycomycetes, including a complete host index and bibliography
Abstract: Tins shall volume on the simple, holocarpic, bi- flagellate Phycomycetes is the second in a series of lectures presented to graduate and research stu- dents o£ mycology at Columbia University on the origin, development, phytogeny, and evolution of the lower organisms.These simple Phycomycetes, with the exception of the Lagenidiaceae, were formerly included in tin-Chytridiales by most mycologists, hut with the recognition in recent decades that the Dumber, position, and relative lengths of the flagella are of fundamental phylogenetic significance, the viewpoint has gradually developed that these species cannot be incorporated in the same order with the posteriorly uniflagellate chytrids.On the basis of present-day evidence, the author concurs with this belief and is accordingly presenting these biflagel- late species apart from the chytrids.Many of these simple fungi exhibit distinct oomycetous characters and tendencies and should perhaps be included di- rectly in existing or new families of the Phycomy- cetes, while the life cycles of other species suggest .1 relationship or at least a parallelism in development with the Plasmodiophorales and Proteomyxa.It is thus impossible at present to include all of them in one family or order and very difficult to assign them to a definite position in a natural system of classification.For this reason they are treated sepa- rately and are referred to here as a heterogeneous collection of simple, holocarpic.biflagellate Phyconiyeetes.This long title is obviously inadequate and can also be extended to include other Phycomycetes not discussed here, the tballi of which may sometimes be holocarpic.A more adequate and briefer title is not available, although the descriptive name Holobiflagellomycetes is suggested.The use of the term "simple" is not to be interpreted as meaning th.it these fungi ;ire primitive and have given rise directly to the higher Oomycetes and Zygomycetes.Nor does the author wish to convey the impression that by discussing these diverse fungi under one title that In-considers them as constituting a natural phy- logenetic series.Whether or not they comprise several distinct families is obviously open to question.The family Wbroninaceae, for example, includes several dissimilar genera and is very doubtful.Should the type species Woroni na polycystis prove to be a member of tin-Plasmodiophorales.as set ins quite likely at present, tin former family name would no longer be tenable.The author has none- theless grouped the genera in five families, realizing fully that the grounds for doing so are woefully inadequate.Mycologists will doubtless disagree with this arrangement, but in our state of meager knowledge concerning many of the genera and species, classification into families is not SO important at present, in the author's opinion, as making available to research students all known facts and data.These fungi have been the subject of study for al- most a century, but no serious attempt has been made to summarize the widely scattered data in zoological and botanical journals.Fischer ('92), Schroeter ('97), and Mindcn ('11) discussed rather fully the species known at the turn of the century, but since that time most textbooks of mycology have given scant attention to them.During the past two dec- ades several new genera and species have been dis- covered, and additional intensive studies on long known species have modified our concepts of host range, sexuality, relationships, etc., within the group.In light of these discoveries and the fact that these simple holocarpic fungi are so significant from the standpoints of phylogeny and evolution of flu- higher Phycomycetes.the author believes that a separate and complete treatment of them is very es- sential and worthwhile, particularly in stimulating research.A full discussion of the doubtful and ex- eluded species is also presented with the purpose of making these data available to researcli workers.Although the author agrees with the view that Ach- lyogeton, so far as it is now known, should be ex- eluded because of its reported posteriorly uniflagel- late zoospores, he nevertheless believes it may possibly prove to be a valid member of the group.In the text which follows very few technical terms are used.A glossary is accordingly unneces- sary and has been omitted.Separate bibliographies are provided at the end of each chapter to expedite reference to the literature on particular subjects, genera, and species.A host index of plant and ani- mal genera and species, together with an inclusive bibliography, is presented in the final chapter.Due to war conditions, many of the recent European and Asiatic journals have not been available, so that this