58 ON THE CLASSIFICATION OF EUCALYPTS, 



The labours of Bentham and Mueller have formed a new era 

 in the history of Eucalyptus. They have enabled us to identify 

 species but little known a quarter of a century ago, and to refer to 

 their proper places in a systematic arrangement all the known 

 Eucalypts. It is to be hoped, therefore, in due course that a "settled 

 nomenclature " may be devised, and that the obscurities arising 

 from '-local names" may be cleared up. In reviewing the 

 different modes adopted for describing and grouping the species, it 

 will be seen that, whilst some of the former characters have been 

 abandoned, or are now only partially relied on, the cortical and 

 anthereal systems have thrown much light on a subject which all 

 botanists, from the days of Brown to the present time, have 

 regarded as beset with many difficulties. 



The first mode of arranging species, as already stated, was 

 founded on the comparative shape and length of the operculum. 

 This method, if adopted only in arranging the specimens of the 

 last century, is now found to be misleading, for the operculum of 

 E. saligna is sometimes conical and sometimes hemispherical, and 

 this seems to have led to some confusion in mixing together the 

 specimens of two very different species, the one a gum-tree, 

 generally with smooth bark (E. saligna), and the other a 

 mahogany with fibrous bark (E. botryoides), and differing very 

 much in habit. As the genus became better known, and more 

 species were added to Willdenow's list, it was found that some had 

 variable opercula, especially in E. viminalis, and the larger forms of 

 E. hcemastoma, E. resinifera, and E. punctata, and that the double 

 opercula were confined to a few species, such as E. globulus, 

 E. maculata, E. eximia, and E. peltata. For a long time, how- 

 ever, the system of classifying by the operculum was continued for 

 the want of any better, and it was sought by means of noting 

 other peculiarities in that organ, and by recording the shape and 

 position of the leaves, to distribute the species with some degree of 

 regularity. Those who paid any attention to Eucalypts before 

 Mueller and Bentham devised their respective systems, are well 

 aware of the mistakes which arose from trusting to any descrip- 

 tions founded simply on the character of the opercula and the 



