PLANT K^OMENCLATURE : A EEPLY l3l 



between one code and another are considerabl}' lessened. If, for 

 example, a genus has been reduced bj segregation to one half of its 

 former size, a change of generic name will affect only half the 

 number of species. The calculations which follow are based on the 

 genera as defined bv Dalla Torre and Harms, with such modifications 

 as are indicated in the lists of "nomina conservanda," e.fj.^ the 

 treatment of Malionia as a separate genus. 



The phanerogamic genera contained in Eritton and Brown's 

 llluafrated Flora, ed. 2, include 101 which are among the "nomina 

 conservanda." These 101 genera are together credited with "Mil 

 species by Dalla Torre and Harms. The number of name-changes 

 of species in the whole body of genera included in the Ilhisfrafcd 

 Flora should therefore be about 3477, according to my rough 

 estimate. How far is this realized ? Let us deal first with the 

 " nomina conservanda " : 75 genera, comprising 1900 species, are 

 invalid under the Code, the remaining 26 genera and 1577 species 

 being valid, owing to the invalidity (under the Code) of the prior 

 names. So far there is a deficiency of 1577 changes. This deficiency 

 is, however, more than counterbalanced b}^ name-changes in genera 

 wdiich are not on the list of " nomina conservanda," and in individual 

 species. Forty-three of these genera, comprising 1068 species, bear 

 different names under the Rules and the Code. A further cause of 

 name-change is the non-validity of specific homonyms. The number 

 of homonyms which are valid under International Rules is difficult 

 to estimate. In Carex alone there ai-e at least T:>^ valid homonyms, 

 and in Astragalus perhaps twice as many. The whole body of 

 genera contained in the Illustrated Flora probably includes at least 

 1000 valid homonyms. Even if we take the number as 500, which is 

 certainly an under-estimate, the total name-changes will amount to 

 at least 3501, made up as follows : — " nomina conservanda," 1900 ; 

 genera not on list, 1068 ; specific homonyms valid under Inter- 

 national Rules, say 500 ; tautonyms, 33. Changes estimated, 101 

 genera, 3477 species — changes ascertained, 118 genera, 3501 species. 

 Thus in a test including between i- and \ of the total estimated 

 name-changes the actual changes are at anj^ rate not less than the 

 estimated; and this in spite of the fact that the estimate was 

 swollen by the inclusion of Fimhristylis, Bhynclwspora,2iY\([ Halenia, 

 which should not have been placed on the list of " nomina con- 

 servanda," inasmuch as the prior names for these genera are invalid 

 under International Rules, having been published either as subgenera 

 or in synonymy. But for the presence of these three genera in the 

 test group, the actual changes would have exceeded the estimate by 

 several hundred. 



Out of 3501 name-changes of species in the test-group of genera 

 1900 (54'3 per cent.) are in respect of " nomina conservanda" ; 500 

 (14*3 per cent.) are attributable to specific homonyms ; 448 (12'S per 

 cent.) are due to the different method of typifying genera ; 233 (6*7 per 

 cent.) to hjqwnyms ; 231 {d-Q per cent.) to generic homonyms; 

 131 (3*7 per cent.) to " priority of place " of genera ; 33 (0*9 per 

 cent.) to tautonyms; and 25 (0-7 per cent.) to genera published 

 without description but with citation of species. 



