U4 PRESIDENTS ADDRESS. 



other eminent authorities, and the line of research is now beina: 

 patiently investigated by one who possesses an intimate know- 

 ledge of our existent flora — my friend Mr. Henry Deane. We 

 have an excellent geological map of New South Wales published 

 by our Geological Survey, but a cursory examination of it shows 

 that it can only be very partially used (in the present state of our 

 knowledge at least) for the purposes of botanical record. This 

 is, however, simply because the records or the geological survey 

 of New South Wales are so much in advance of the botanical 

 ones. 



6. THE DISTRIBUTION OF PLANTS AFFECTED BY VOLCANIC 

 OUTBURSTS. 



In this matter of plant-distribution, when one contemplates 

 apparent gaps in species between northern and southern localities, 

 e.g., when certain species common on the southern tableland give 

 the Port Jackson district a wide berth and make their reappear- 

 ance in, say, New England, one may ask, to what extent is the 

 destruction of forests caused by volcanic outbursts responsible 

 for the gaps in the sequence of forests in Australia % Mr. J . J. 

 Fletcher has pointed out to me that Prof. R. Tate has discussed 

 the matter^' in connection with the paucity of land-moll u sea in 

 Victoria, but as regards the destruction (if such occurred) of the 

 flora. I do not know whether geologists have published any 

 evidence on the subject. It is only proper to reiterate that the 

 records of a botanical survey are so very imperfect, that one must 

 proceed very cautiousl}^ in stating that there are any gaps in the 

 flora which may not be attributed to denudation of the soil and 

 other causes, and where gaps appear it is because observation 

 has not yet shown that there is an irregular line of continuity of 

 occurrencef in any particular species. The student of ecology 

 will very carefully endeavour to trace these lines of occurrence 

 of particular (at all events of important) species, and I do not 

 doubt that full data thus collected will prove of real value to the 



* Proc. E. S. S.A. iv. 73-4. 

 t Dr. B. L. Kobinson's "Carving Boundary," o-p. cit. 



