108 REPORTS ON THE STATE OP SCIENCE. — 1915. 



This appears to be the newest group of Eucalypts ; they have been 

 evolved in the southern or cool and moist regions. Owing to the final 

 uplift which formed the Main Divide, north and south, and perhaps 

 assisted by the Pleistocene glaciation period, this type has been able 

 to migrate northwards along the higher portions of the range to the 

 borders of Queensland (1). 



Eucalyptus leaves with transverse venation are absent from 

 Tasmania and are confined to a very small portion of north-eastern 

 Victoria. They are feund practically below the 3,000-feet level in New 

 South Wales but are common on siliceous soils in Northern Australia, 

 thus showing a preference for the warmer climate. Eucalyptus trees 

 possessing leaves with parallel venation occur in Tasmania, Victoria 

 and Eastern New South Wales, whilst in Northern New South Wales 

 their home is above the 3,000-feet level; they are absent from Northern 

 and Western Australia but are found at the highest level at which any 

 Eucalyptus grows in Australia, viz. 6,500 feet, thus showing a pre- 

 ference for cold and moist conditions. 



Briefly, then, we have the early Eucalypts growing in a sandy soil 

 with a warm climate, with leaves containing pinene and characterised 

 by a transverse venation, the anthers belonging to the section Parallel- 

 antherse. 



Secondly — partly as a result of alteration in climate and partly from 

 the presence of more basic soils, perhaps also the influence of other 

 causes — a new type was evolved in which cineol became an important 

 constituent of the oil, the leaves having a more oblique venation, the 

 anthers opening in parallel slits or terminal pores. 



Thirdly — chiefly as a I'esult of the Eucalypts migrating to southern 

 cooler latitudes and climbing up the newly uplifted mountains — a 

 further type was evolved ; many of the species contained much phellan- 

 drene, pinene being either absent or reduced to a trace; in this type 

 the leaves commonly have parallel venation and the anthers usually 

 belong to the section Renantherse. 



The Correlation between Specific Characters of the Tasmanian and 

 Australian Eucalypts. By E. T. B.-vker and H. G. Smith. 



• In a letter which the late Sir Joseph Dalton Hooker wrote to us 

 he expressed a wish to see a research undertaken to investigate what 

 affinities, if any, there were between the Gum-ti'ees of the mainland 

 and those of Tasmania; being particularly interested in the subject, 

 having desci-ibed and collected species from the higher altitudes of that 

 island, he regretted he had not been able to collect material at 

 corresponding heights of Australia for the purpose of comparison. 



This investigation has been undertaken by us and the results are 

 of more than passing scientific interest, as it is found that when a 

 species occurs both in Tasmania and on the opposite mainland it has not 

 only identical morphological but also similar chemical characters ; some 

 species and even groups of wide geogi'aphical range on the mainland 

 are found, however, to be absent from the daughter island (23). 



The absence or presence of these species seems to be accounted 

 for on tracing out the evolution of the Genus. In our work on the 



