66 ON THE CLASSIFICATION OF EUCALYPTS. 



mistakes arising from the abnormal state of the hark may be 

 rectified. To the passage already quoted I added, " As regards 

 the fixing of species and of ascertaining the amount of variation 

 to which some are liable, other principles must be applied. Some 

 species, indeed, are marked by the double operculum, some by 

 winged seeds, and others by the colour of their stamens ; but the 

 shape, cells, valves, &c, of the seed-vessels present very important 

 notes of distinction and deserve the most attentive study. Hence 

 I believe that these considerations, when taken in connection with 

 the cortical group to which the respective species belong, will be 

 found most efficacious in settling many difficulties." Since 1860, 

 Baron Mueller has made wonderful progress in the description of 

 new species and in illustrating their peculiar properties, but I still 

 think that if any further improvement is to be made in the matter 

 of classification, it must be by the study of their fruits. To collect 

 the fruits of all known Eucalypts, and to form groups on the basis 

 I have suggested, would be the work of time and might need 

 almost a specialist ; but if it be true, as the Baron is fond of saying, 

 that not only in religion but in the study of the vegetable kingdom, 

 species are known by their fruits, it may reasonably be expected 

 that to the cortical and anthereal systems, a carpological one may 

 yet be added, which will dissipate the obscurity which still rests 

 on the true characters of some species, and render the study of 

 Eucalyptus as practicable as that of any other genus. Some of our 

 great naturalists have been so impressed with the importance of 

 the fruit and its seed, as * constituting the crown and end of the 

 whole nature and vitality of plants/' that they have not hesitated 

 to regard them as superior to the other parts in dignity; and 

 probably, if the fruits of all our Eucalypts could be procured and 

 arranged systematically according to their variations, additional 

 light would be thrown on the matter of classification. Baron F. 

 von Mueller has already hinted at this in his l£ucalyptographia f 

 and should he be spared to take a comprehensive view of the 

 whole genus (including the species of those Eucalypts which at 

 present are but partially known), he would add, if it were possible, 

 to the world-wide reputation he has already acquired. 



