The nomenclature of fossil plants.

ARTICLE 9 of the International Rules of Botanical Nomenclature2 provides that "the rules and recommendations of botanical nomenclature apply to all classes of the plant kingdom, recent and fossil, with certain distinctly specified exceptions." However, examination of the Rules soon reveals that certain important aspects of the nomenclature of fossil plants are not yet covered by specific articles and recommendations. To remedy this condition, several sets of new proposals have been advanced, notably those by Jongmans, Halle, and Gothan,3 those by British paleobotanists,4 and those recently formulated by American paleobotanists. These three groups of proposals are representative of the opinions held by many paleobotanists, whereas the proposals of Dubois-Ladurantie and Gaussen5 and Hylander6 are the outgrowths of individual efforts to resolve the existing difficulties. Although these sets of proposals differ in various ways from one another and the Rules, most of them prove that the existing framework of the latter is capable of expansion and correction to cover paleobotanical nomenclature. As the actual proposals either have been published, or, like the American proposals, are to be published in the near future, the main part of the following discussion will deal with the more important aspects of paleobotanical nomenclature represented by the latter. A brief comment regarding the American Committee on Paleobotanical Nomenclature may here be in order. Founded shortly before the war,7 and hampered at first by it, the original Committee was replaced by the present one in March, 1947. The Droposals received and acted upon by the present 1 For their active participation, either in formulating proposals or by critical reading of the manuscript, the author is greatly indebted to Dr. E. E. Sherff, Chairman of the Symposium; Dr. W. H. Camp, Chairman of the Committee on Nomenclature, American Society of Plant Taxonomists; to the members of the Committee on Paleobotanical Nomenclature, Drs. J. H. Johnson, H. L. Mason, and N. W. Radforth; and to several colleagues, especially Drs. J. M. Schopf, H. N. Andrews, Jr., and C. A. Arnold. 2 Bisby, G. R. An Introduction to the Taxonomy and Nomenclature of Fungi. Kew. 1945. Camp, W. H., H. W. Rickett, and C. A. Weatherby. International Rules of Botanical Nomenclature. Brittonia 6: 1-120. 1947. 3 Jongmans, W., T. G. Halle, and W. Gothan. Proposed Additions to the International Rules of Botanical Nomenclature. Adopted by the Fifth International Botanical Congress Cambridge 1930. Heerlen. 1935. 4 Thomas, H. H. Proposed Additions to the International Rules of Botanical Nomenclature. Suggested by British Paleobotanists. Jour. Bot. 73: 111-113. 1935. 5 Dubois-Ladurantie, G., et H. Gaussen. Projet de Nomenclature Paleobotanique. Bull. Soc. d'Hist. Nat. Toulouse 76:289-295. 1941. 6 Hylander, Nils. International Rules of Scientific Botanical Nomenclature-A New Proposal. 1948. 7 Schopf, J. M. American Committee on Paleobotanical Nomenclature. Chronica Botanica 7: 226-227. 1942. Committee will be published, together with those submitted to the Committee on Nomenclature of the American Society of Plant Taxonomists.8 The resulting publication will contain the complete text of all proposals and the accompanying arguments, together with the names of the respective authors. As a group, the American paleobotanical proposals readily reflect the spirit of the Rules. For, if adopted, they are likely to effect the least number of nomenclatural changes toward the eventual stabilization of paleobotanical nomenclature. EXCEPTIONS TO THE PRINCIPLE OF PRIORITY.The recent discovery in China of a living Metasequoia,9 quickly resulted in a new proposal badly needed for the selection of types, if names of related living and fossil plants are involved.10 Its published version has just been modified bv its author and as such approved by the two American committees mentioned above. It now reads as follows: "Names based on types derived from modern material always take nomenclatural precedence over names permanently attached to specimens of fossil or subfossil character." The reason for this proposal, its bearing on similar cases, and possible implications for future paleobotanical discoveries have been stated by its author and need not be detailed again. It is interesting to note, however, that no similar proposal has been incorporated among the various recommendations by European paleobotanists. Although this proposal would actually sanction occasional departures from the principle of priority as stipulated in the Rules, such instances are not likely to be very numerous. In fact, the number of exceptions to the consistent application of the principle of priority resulting from the adoption of this proposal will be small compared with the many names bound to appear on the projected list of nomina generica conservanda of fossil plants. An objection concerns the possibility of confusion arising from the converse application of the names of fossil plants to living plants. Although this problem exists, it is not very serious. According to art. 61, names of fossil plants applied to living