54 ON THE CLASSIFICATION OF EUCALYPTS, 



had noticed with a view to classification that the variations in the 

 stamens afforded a means whereby species might be grouped 

 together; but Mr. Bentham, in arranging the species of Eucalyptus 

 in the Flora Australiensis, not only described with accuracy the 

 form of the anthers in each species, but made the variations a 

 basis for the elaboration of his anthereal system. In the Flora, 

 Vol. in. (1866), that eminent botanist tells us of the difficulties he 

 had experienced in grouping the species. The comparative length 

 of the operculum, the shape and position of the leaves, the character 

 of the inflorescence and fruit, and the nature of the bark (of which 

 in dried specimens he was totally unable to judge), had all failed 

 to give him a satisfactory mode of classification. He says : — " I 

 have thus been compelled to establish groups upon such characters 

 as appeared to me the most constant among those which are 

 supplied by the specimens : in the first place upon the form of the 

 anthers, and secondly upon that of the fruit, and in some cases on 

 the inflorescence or the calyx." It is evident that Mr. Bentham 

 regarded his arrangement as simply provisional, for he expresses a 

 hope that Baron Mueller, " from his knowledge of the gum-trees 

 in a living state, might be able to devise a truly natural arrange- 

 ment founded upon the proposed cortical system, or any other 

 system which experience may induce him to adopt." 



So far as the stamens are concerned, Mr. Bentham grouped the 

 species in the following manner : — 

 Series I. — Renantherce, or such as have the anthers reniform or 



broad and flat. 

 Series II. — Heterostemones, or those which have the outer stamens 



anantherous. 

 Series III. — Porantherw, or those that have small and globular 



anthers. 

 Series IV. — Micrantherce, or those having small globular anthers. 

 Series V. — Normales, or those with oblong-ovate or nearly globose- 

 anthers opening longitudinally. 

 The other series are founded on the inflorescence, the shape of 

 the calyx, the position of the valves in the fruit, and the nature of 

 the fruit itself. 



