Validity of Callitris Morrosoni 105 



4. A cliemical investigation of their oils, saiidaraclis, camphors 



tfec. 

 f). And lastly the aid of the physicist (wliich supports this 

 differentiation) has been laid under tribute. 



Tlie result of ail this has been the accumulation of specific data 

 that leave no alternative but to differentiate all these species 

 enumerated (supra). That is, if differences constitute a species, 

 as T believe they do. 



It would be asking the Royal Society too much to publish here 

 all the results obtained in this connection, in order to prove the 

 case, but it is hoped they will be in print next year. 



I might, however, state en passant tliat, concerning two of the 

 proposed varietal forms, i.e. verrucosa and columellarLs, these two 

 morphologically, cortically, ligneously, chemically, and physio- 

 logically are quite different, and again any one who has compared 

 only the timbers of intratropica and microcarpa would hardly be 

 prepared to say they also are one and the same species. 



Unfortunately Professor Ewartdoes not say to which C. robusta 

 his x'emarks refer. It was to clear the identity of this species 

 more especially that the European herbaria were visited by me, 

 for in my opinion it was hopeless to do it in Australia, and this 

 was especially impressed on me after reading De Candolle's list of 

 doubtful and excluded species of Callitris, [Prodromus. vol. IG. 

 pp. 451-3]. 



To place ;i]l those Callitris enumerated by Professor Ewart 

 under one species would be a parallel case to that of Baron von 

 Mueller, who when dealing with Eucalyptus amygdalina, Labill, 

 synonymised at least half a dozen good species under this name, 

 which can all be shown to pos.se.ss distinctive nioi'phological, 

 cortical, chemical, and other physiological differences from La 

 Billardiere's species. 



The.se two ca.ses are only another illustration of the failure of 

 morp]wh\^y alone in the determination of species in Eucalypts 

 and Callitris. 



In this connection no better example can be quoted than that 

 of Eucalyptus niaculata and E. citriodora. Both species were 

 established by Hooker, and later weie synonymised l>y Baron von 

 Mueller because morphologically the leaves and fruits were 

 identical. .-> 



