'7 



Angophora lanceolata, Cav., and was found to contain identical constituents to 

 those obtained from the ' Bloodwoods " jusl mentioned. Hie sesquiterpene 

 (aromadendrene) which occurs in some quantit} in .ill this group oi Eucalypts, 

 was also presenl in the oil of Angophora lanceolata, as it gave the characterise 

 colour reaction for thai constituent with bromim Foi tl ential oils oi 



the Angophoras, see paper l>\ one of us, Roy. So< .. N.S.W . Vug., [913. 



In August, in<)<>. a paper was read l>\ one oi us (Roy. Soc, N.S.W.) on .1 

 crystalline substance obtained from the exudation, or kino, oi the " Red Gum 

 (/■'. cahphylla), sent to the Museum by the Bureau oi Agriculture, Western 

 Australia; this substance was named aromadendrin. In the description oi .1 

 new Angophora 1 I. melanoyxlon) , by one of us (Proc. Linn. So< ., N.S.W., 1900), 

 the announcemenl was made thai the kino oi this tree contained aromadendrin, 

 it being chemicallj identical with that described from E. calophylla. The 

 chemical evidence relating to the affinity of these genera which has since 

 accumulated, shows the connection to be somewhat complete. 



Assuming the Angophora to be the older genus, we have endeavoured 

 to formulate, on data similar In the above, a table or " tree." showing the supposed 

 line of origin of the various groups of Eucalypts from the appareni initiation 

 of the Genus. The table will be found a1 the end of this article, and .1 map oi 

 Australia indicating more fully the territorial distribution in connection with 

 this evolution table is also added. The table includes the majority of the 

 species of Eastern and Southern Australia, but when those "I Northern and 

 Western Australia shall have been more fully investigated on similar lines, :| 

 more complete tabulation will be possible, as then, no doubt, many of the 

 connecting links which are at present felt to be wanting, will be forthcoming. 

 We do not think that the investigation of those species will interfere materially 

 with the main principle of evolution as here laid down. 



Proceeding from the 'Bloodwoods," it is possible, from the evidence 

 available, that the line of descent was through /'.'. saligna and E. botryoides, the 

 venations (plate in), together with the chemical constituents of the oils, being 

 very closely allied to those of the " Bloodwoods." In the oil of /■;. saligna 

 cineol is making its appearance, for, although present but in small amount, it 

 could be detected quite satisfactorily. 



If botanical features are considered in conjunction with those of the 

 ■ hemical, it is seen that as the characteristic constituents of the oils vary in 

 amount and change their character, so do the trees form well-defined groups. 



For instance those seceding from the " r.l Lwoods " apparently pass 



in three directions, one through the " Stringy barks " to the group oi " Peppei 

 mints," another through the " [ronbarks " to that large group which includes 

 the cineol-pinene oils generally, or those in which the terpene phellandrene is 

 absent, and thirdly through one section of the " Stringybarks " particularly 

 E. obliqua, — to the other large group which includes the typical "Boxes" and 

 their associated " Mallees." The Genus may thus be considered as embracing 

 four large groups which may be indicated, chemically, as follows : 



(a) Those yielding 01b consisting largelj of the terpene pinene; either 



dextro-rotatory or laevo 1 otatory. 



(b) Those yielding oils containing varying amounts ol pinene and cineol 



but in which phellandrene is absi 



(c) Those yielding oils in which aromadendral 1- a characteristic constituent. 



and phellandrene usually absent. 

 ((/) Those yielding oils in which the terpene phellandrene is a pronounced 

 1 onstituenl . with piperitone mostlj present. 



50068— B 



