560 DEVELOPMENT OF THE N.O. MYRTACEJR, 



and Ironbarks established themselves, in part, upon this, and be- 

 came so modified in the process, that the links connecting this 

 group and the earlier Bloodwoods, have practically vanished. 



Similarly, as the eastern periphery of Australia became 

 roughened, two other, but allied, groups of Eucalypts gradually 

 developed in the more southern portions, and as the climate became 

 colder, they slowly extended their way northwards. These groups 

 include the Stringy barks, Peppermints, Mountain- Ashes, Messmates 

 and the majority of the Mountain-Gums. They possess peculiar, 

 kidney-shaped anthers, which again fall naturally into two types; 

 they also possess a peculiar leaf -venation, and their oils are like- 

 wise characteristic* 



With the formation of the great plateaus of Eastern Australia 

 during the Kosciusko-Period, the Eastern Eucalypts became 

 differentiated into fresh species and varieties, while the Boxes, 

 Ironbarks, and Bloodwoods remained but slightly modified. 



Thus, at present, along the highlands of Victoria, New South 

 Wales, and Southern Queensland, may be seen the effect of rein- 

 vasion by forms of Eucalypts, which had been developed in 

 regions further to the south. 



* In attempting to work out a scheme for the evolution of the Eucalypts, 

 special attention should be directed to anthers, leaves, oils, soil, and 

 climate. With regard to anthers, the work of Bentham, von Mueller, and 

 Maiden is invaluable. So important a factor did the anthers appear to 

 the great Bentham, that he actually established a sound classification of 

 the Eucalypts upon such basis, its imperfections being due merely to his 

 lack of knowledge of the growing plants and their environment. This 

 difficult task, commenced by Bentham, is being carried on by Mr. J. H. 

 Maiden, whose views have been, and are being, expressed in the "Critical 

 Revision of the Eucalypts" and "The Forest Flora." The work also of 

 Baker and Smith is highly important in Eucalypt-studies. The great 

 resemblance between Angophora and the Corymbosse Eucalypts is clearly 

 pointed out by them. Especially clearly have they shown the intimate 

 relations existing between the development of the leaves and the oils of 

 the genus, as also the relations existing between the Peppermint and 

 Stringybark groups. Recently, the influence of the soils, and the climate 

 has been perceived by Mr. Cambage; and he has accomplished the difficult 

 and highly important task of co-ordinating the different lines of evidence 

 yielded by a study of soil and climate. 



