American Code and Later Lectotypifications of Linnaean Generic Names Dating From 1753: A Case Study of Discrepancies

Summary The typification of the 112 Linnaean generic names dating to 1753, for which American Code lectotypifications differ from later ones, is reviewed in the light of two proposals to amend the International Code of Botanical Nomenclature at the XIV International Botanical Congress at Berlin in 1987. As part of the review,Dioscorea sativaL. is lectotypified and thus synonymized underD. villosa, andAgrostis albaL. is placed in synonymy underPoa nemoralisL. The two proposals (Proposals 291 and 297) were both included in the report of the Committee on Lectotypification, and are found to have differential effects in 58 of the 112 cases examined. It is shown that adoption of the provision to remove all constraints on the priority of American Code lectotypifications would result in nomenclatural changes in 48 cases as against 10 if the proposal to adopt 1935 as the starting date for priority of lectotypification was adopted. Moreover, with priority of American Code lectotypifications, changes would arise in the names of subdivisions of families in 4 cases and in names very widely accepted at the generic level in 21 cases, whereas no such changes would occur if a 1935 starting date were adopted. The generic names involved includeAgrostis, A ndropogon, Apium, Cleome, Cucurbita, Draba, Elymus, Ophrys, Scabiosa, ScirpusandSisymbrium.At the infrageneric level (including 7 cases in which a few authors recognize segregate genera), changes would be required in 26 cases if Proposal 297 (American Code priority) were adopted on its own, but in only 10 if Proposal 291 (1935 start) were accepted. The authors conclude that stability of nomenclature, at least at the levels of genera and subdivisions of genera of phanerogams, is better served by establishing 1935 as the starting date for priority of lectotypification.