52 ON THE CLASSIFICATION OF EUCALYPTS, 



No change was proposed for the classification of the Eucalypts 

 until 1858, when Baron Mueller, in a paper read before the 

 Linnean Society, suggested what may be termed the " cortical 

 system," or a mode of arranging the species according to the 

 structure of the bark, whilst at the same time he directed atten- 

 tion to the valves of the fruit as affording an additional character 

 for the identification of species. The Baron's monograph refers 

 especially to the Eucalypts of tropical or sub-tropi<al Australia, 

 but the suggestions contained in it may be applied to the whole 

 genus, and they have certainly proved exceedingly useful in 

 determining species previously doubtful, and of showing that the 

 comparative length of the operculum is not always a safe guide. 



The Baron, in offering the cortical system as a contribution 

 towards the better arrangement of the Eucalypts, speaks of it as 

 one accommodated to the use of the colonists, regarding it evidently 

 as a popular way of grouping the species according to their 

 appearance in a living state, and of ascertaining whether it might 

 not ultimately afford a means of placing them in appropriate 

 sections. He proposed, therefore, to divide the genus into six 

 sections : — 



(1) Leiophloice, or smooth-barked trees, such, for instance, as the 



" White," " Blue," and " Red Gums." 



(2) He?niphloicB, or half-barked trees, as " Box" and " Blackbutt." 



(3) Bhytiphloice, or trees with wrinkled persistent bark, as 



" Bloodwood," and " Peppermint." 



(4) Pachyphloice, or trees with persistent fibrous bark, as "Stringy- 



bark " and the " Mahoganies." 



(5) Schizophloicr, or trees with persistent deeply furrowed bark, 



as the " Ironbarks." 



(6) Lejridoiohloice, or trees with the bark persistent on the trunk 



only, and forming separate pieces, as the " Moreton Bay Ash." 



The 38 species enumerated by the Baron are arranged in the 

 following manner : — 



