The American Code, the Vienna Code and the resolutions of the Imperial Botanical Conference in London. Will agreement be possible in 1930?

„The two codes have been a great help in stabilizing nomenclature. Experience has shown, however, that they lack definiteness in directing the application of names ...” (HITCHCOCK in Am. Journ. of Bot. May 1921 p. 251). „A harmonizing of the two codes appears to be impossible, if it is maintained that the International Rules cannot be modified in any essential, but only added to or interpreted. This is the belief in some quarters ¹), but I find no confirmation of this in the Rules themselves and it is contrary to the spirit of codes and laws in general. They should be modified to accord with the consensus of botanical opinions ²). Otherwise they will be gradually abandoned.” (H. in Br. Journ. of Bot. Nov. 1922 p. 318; the same opinion is uttered by WILLMOTT on p. 196, and by SPRAGUE in J. of B. 1924 p. 197).