PRESIDENTIAL ADDRESS. 35 



no red-timbered Eucalypt occurring in Tasmania. 1 The 

 colouring of dark timbers is evidently due to the presence 

 of some constituent, perhaps developed in response to a 

 plant food, and it seems not improbable that the develop- 

 ment of the substance in question is retarded by the cold. 

 The wood of mountain Eucalypts is also regarded as the 

 least valuable for firewood among the genus, which fact 

 implies some difference in the composition of many lowland 

 and highland Eucalyptus timbers. 



Now under the peneplain conditions, long prior to the 

 Kosciusko period, a greater similarity in the texture of 

 Eucalyptus timbers in South Eastern Australia would 

 undoubtedly have existed over at least the Coastal, Moun- 

 tain, and Western Slopes divisions, and it seems a fair 

 inference that the great uplift in that period is responsible 

 for accentuating, even though an earlier and slighter uplift 

 may have helped to originate, some of the various differ- 

 ences in the textures of these timbers. 



Leaves. 



Perhaps it is in the leaves of Eucalypts, when the 

 significance of their many and varied forms is better 

 understood, that much of the past history of this genus 

 will be revealed. The leaves may be regarded in a measure 

 as the chemical laboratory and lungs of the tree, and in 

 order to preserve themselves in a fitting manner to carry 

 out their starch-producing and breathing functions, it is 

 well known that the leaves of Eucalypts have become 

 modified in various ways in response to their environment. 

 While they have undoubtedly adopted various means of 

 combating the same injurious influence, on the other hand 

 they have resorted to the same expedient to overcome 



1 Messrs. E. T. Baker, f.l.s., and H. G. Smith, f.c.s., make some 

 reference to this subject in a paper " A Kesearch on the Eucalypts of 

 Tasmania and their Essential Oils," read before the Royal Society of 

 Tasmania in October 1912, Pap. and Proc. Roy. Soc. of Tasmania, p. 139. 



