120 



PLANT NOMENCLATURE . A REPLY. 

 Br T. A. SpKAauE, B.Sc, F.L.S. 



The publication of my '* Siigi^estions " ( Journ. Pot. 1921, lo;j- 

 1(50) has elicited criticism from various sources. Dr. N. L. Pritton, 

 on the one side, rcii^ards those suggestions which are in accordance 

 with the American Code as " quite in the line of progress," and those 

 which conrtict with it as " not in line of progress towards nomencla- 

 torial stability" {op. cit. 296). Drs. Schinz and Thellung, on the 

 other side, consider that no dehnite decision of the Vienna Congress 

 should be reversed, whatever may be the merits of the case, as to do 

 so might, in their opinion, lead to a return of anarchic conditions in 

 nomenclature (Vierteljahrsschr. Nat. Ges. Ziirich, Ixvi. 311 ; 1921). 

 Put disregard of the International Rules would be more likely to 

 result from the retention of unwise Articles (such as Art. 3G) than 

 from their revocation or modihcation in accordance with prevailino- 

 opinion. 



The impersonal character of the discussion and the desire generally 

 shown to combine the best features of both nomenclatural systems 

 are encouraging. No permanent agreement can be attained without 

 dispassionate comparison of rules, and adequate tests of their effects 

 in practice. It is of primary importance that we should be agreed as 

 to the facts, and as Dr. E. W. Pennell's article (Journ. Pot. 1922, 112) 

 may convey a wrong impression of the amount of difference in 

 nomenclature under the two sj^stems, it seems desirable to deal with 

 it in the first place. 



Name-ciiaxges required under the American Code. 



Dr. Pennell challenges my estimate of the number of name- 

 changes which the adoption of the American Code would require. 

 To make matters clear, I quote my original statement : '• A rough 

 idea of the number of name-changes required under the Code may be 

 gained from the total number of species affected by the ' noinina 

 conservanda ' of the Rules. These amount to more than 15,000 out 

 of a total of 136,000 Seed-Plants ; that is to say, one species out of 

 every nine. The figures are taken from Dalla Torre & Hanns, Gen. 

 Siphonog. (1900-7) ; and Thonner, Pliitenpfi. Afr. 623 (1908)." 



He states that I assumed that all the " nomina conservanda " 

 adopted by the Vienna Congress were invalid according to the Ameri- 

 can Code. In this he is mistaken. The underlying assumption was 

 that the deductions which must be made in respect of " nomina 

 conservanda " that are valid under the Code are counter-balanced by 

 additions due to various causes. Has he forgotten that the recogni- 

 tion of "nomina conservanda" is only one — though admittedly tlie 

 most important — of the sources of difference in nomenclature ? 

 Among other causes of difference I may mention the following: — 



(1) The rejection under the Code of untypified genera (hyponyms). 



(2) The rejection under the Code of homonyms, generic and 

 specific. 



Journal or Botany. — Vol. 60. [May, 1922.] k 



