PRESIDENTIAL ADDRESS. 51 



The somewhat meagre fossil evidence available rather 

 supports the idea that the transverse venation belongs to 

 the earliest form of Eucalyptus leaf, while it also goes to 

 show that even the extreme or parallel type of venation 

 flourished in the south as far back at least as the Miocene 

 period. After the Kosciusko uplift, and perhaps assisted 

 by the glacial period in Pleistocene time, this latter type 

 was enabled to invade New South Wales from south to 

 north by travelling along the Main Divide. 

 Inflorescence. 



Anther. — The only portion of the flower which I propose 

 to discuss is the anther, and this is the most important 

 part of the inflorescence from a diagnostic point of view. 

 Bentham, in that classical work, the Flora Australiensis, 

 was the first to group the Eucalypts according to the anthers. 

 He arranged them into five sections which Baron von 

 Mueller reduced to three on finding difficulties in main- 

 taining the larger number separately. 1 My remarks will 

 be confined to the three groups viz.: — 



Parallelantherce. — The cells and consequently the longi- 

 tudinal slits parallel. 



Porantherce. — The anthers small and opening in pores. 



Renantherce. — The anthers fairly large, the cells diver- 

 gent at the base, and confluent at the summit. 



In a large genus like Eucalyptus it is not surprising to 

 find that there is a gradation of characters from one species 

 to another, and this varietal tendency applies in a marked 

 degree to the anthers. But on studying the distribution 

 of the three general types of anther, it becomes evident 

 that to some extent such distribution is regulated by 

 climatic influence, or that a certain form of anther is often 

 better represented in one class of climate than another. 



1 For remarks concerning variation of anthers, see "A Critical Eevision 

 of the Genus Eucalyptus/' by J. H. Maiden, f.l.s., Part I, p. 11. 



