554 DEVELOPMENT OF THE N.O. MYRTACBjE, 



points impress the student, at the very outset, in the study of 

 Eucalyptus. 



(l)It did not spring from a depauperate type. 



(2) It is intimately related to Angophora, Tristania, Metrosideros 

 and Syncarpia. 



(3) Its earliest leaves were opposite, cordate, sessile and peculiar- 

 ly veined. 



(4) Its stamens are frequently very brightly coloured in some 

 Northern and Western Australian species. 



(5) It is separated into several groups, quite distinct from each 

 other, and with little or no trace of connecting links. 



(6) It is a type adapted either to resist hot, subarid, or cold, 

 moist conditions, in the main, by reason of its operculum, its oil- 

 contents, its wax-like bloom, its twisted leafstalks, its thick leaves, 

 its enlarged root-stocks, as well as other adaptations. 



(7) It has little or no striking morphological resemblance to the 

 Euleptospermese and the Beaufortieae, except for the long and 

 brightly coloured stamens. 



It would appear that both the Eucalyptege and the Euleptosper- 

 meae were, in the first instance, an organic response to a poor soil, 

 and only secondly, after a long lapse of time, to a drying climate. 



With regard to the question of its evident adaptation, in the first 

 place, to a poor soil, and next to a subarid climate, it seems impos- 

 sible for such a type to have existed in America, Europe, and Asia 

 during the Cretaceous, when the types of plants found, are such as 

 do not at all suggest arid or subarid conditions. Deane has ad- 

 vanced cogent reasons* in support of the growing belief that the 

 older determinations of Eucalyptus in the Cretaceous and Tertiary 

 of the Northern Hemisphere, by Ettingshausen, cannot be accepted. 

 Hooker (quoted by A. R. Wallace, in "Island Life," p. 486) also 

 appears to have considered the determinations of fossil Eucalypt- 

 remains, in the Tertiary and Cretaceous of the Northern Hemi- 

 sphere, as valueless. Bentham also appears to have disbelieved 



* See " Observations on the Tertiary Flora of Australia." These Pro- 

 ceedings, xxv., 1900. See also R. H. Cambage, " Development and Dis- 

 tribution of the Genus Eucalyptus," Presidential Address, Jouru. Proc. 

 Roy. Soc. N. S. Wales, 1913. 



