562 DEVELOPMENT OF THE N.O. MYRTACEM, 



obliqua, E. dives, E. amygdalina, E. piperita, E. Bisdoni, E. 

 pilularis, E. capitellata, E. Icevopinea, E. eugenioides, E. macro- 

 rhyncha, E. Muelleriana, etc. 



Specialised or aberrant forms include E. coriacea, E. stelhdata, 

 E. cocci/era, E. vitrea, E. Smithii, E. acmenioides, and E. micro- 

 corys, the last two varying in the opposite direction to that 

 taken by the first-named four types. A careful examination of 

 E. buprestium, E. marginata, and E. santalifolia from W. Aus- 

 tralia indicates that they are specialised forms only of Bentham's 

 Normales, and are only analogous forms to what are here called 

 the true Eucalypts (Renantherse of Bentham). Moreover, the 

 study of the geographical conditions shows that the Eucalypts, 

 of which E. obliqua is the type, have originated in the moun- 

 tainous topography of South-eastern Australia, at a time during 

 which the climate and topography of the region separating 

 Western from South-eastern Australia, have been such as to forbid 

 the migration of the E. obliqua-type to the west. In Western 

 Australia, one finds only the Normales-type, with its peculiar 

 aberrant or specialised forms. Even the great Section of the 

 Porantherse is there unrepresented. Moreover, E. buprestium, 

 E. marginata, and E. santalifolia have neither phellandrene nor 

 piperitone contents. Thus they may be removed from the true 

 Eucalypts. 



Types, such as E. corymbosa, E. setosa, E. miniata, E. ficifolia, 

 E. calophylla, E. terminalis, E. trachyphloia, E. eximia, E. 

 peltata, E. perfoliata, E. Abergiana and E '. ferruginea, might be 

 called Corymbosa. In this, as in some other groups, the bark is 

 not to be relied upon always for purposes of natural classification. 

 In the earlier types of the genus, it appears to have been thick, 

 and more or less charged with kinos and other material for the 

 purpose of resisting the excessive transpiration to which the 

 ancestral form of the primitive type had been a stranger; but 

 with types such as E. maculata and E. tesselaris, this property 

 could be dispensed with, owing to the ability of such later forms 

 to reach a water-supply easily. Nevertheless, vestigial traces of 

 the primitive, thick bark remain still on these types. E. coriacea, 

 E. stellulata, E. hcemastoma, E, vitrea, and E. cocci/era are still 



