334 J. H. MAIDEN. 



in indicating differences in the several species or that is more con- 

 clusive in its results, than is the practical constancy of chemical 

 constituents in identical species, a fact of the greatest scientific 

 and economic importance." 



By "identical species" it is not certain whether botanical 

 or chemical species are referred to. And again: — 



"That the constituents have been fixed and constant in the oils 

 of the several Eucalypts for a very long period of time." 



It is added that the venation of the leaves and their 

 botanical characters " show also a marked constancy." 

 All this comparative constancy is probably accounted for 

 by the long period of time that must have elapsed before 

 a particular species could have established itself as such 

 over so extensive a range as we And species to-day. 



"The chemical and botanical peculiarities must also have been 

 fixed primarily, because we do not find the differences in characters 

 one might expect by environment. Our researches seem to show 

 that the species are only well marked varieties in which the dis- 

 tinctive characters have become permanent." 1 (The italics are mine). 



These statements are quite definite. The authors state 

 that the genus Eucalyptus has now become fixed. 



By what authority can anyone venture to say that 

 variation has ceased in the genus ? I regret that such a 

 statement has been made, as it seems to be specially 

 unfortunate. In view of the evidence I have already 

 adduced, I imagine most botanists will agree that the genus 

 is as variable as Rubus, Rosa, Hieracium, Cinchona, or 

 Salix. 



A friend humorously expressed the situation by saying, 

 "There is so much variation that there is really but one 

 species, and its name is Eucalyptus australis." The late 

 Rev. Dr. Abbott made a somewhat similar utterance when, 



1 Baker and Smith, this Journal, xxxv., 122, 123. 



