A CRITICAL REVISION OF THE 

 GENUS EUCALYPTUS. 



A.— Variation in the Genus. 



The genus Eucalyptus is such a large one that a number of schemes have been 

 submitted for dividing it into sections with a view of associating those closely 

 allied, or for arriving at the name of a species with facility. These schemes will 

 be referred to in the bibliography, and I now propose to review each character, 

 from timber to anther, to see if any satisfactory scheme can be evolved. In the 

 Proc. Aust. Assoc, for Adv. of Science, Sydney Meeting, 1898, Professor Tate* 

 and Mr. Luehmannf simultaneously gave prominence to the use of the fruit for 

 purposes of classification. Both papers take cognizance of other characters as well. 

 Both are the work of men who know the genus, and are valuable contributions to 

 knowledge. 



o 



Ha))it. — Tate defines two habits of growth, viz : — Trees, and shrubby, 

 stocky trees, to which he applies the vernacular names of gums and mallees, 

 names well understood in Australia. He points out that in young plants of the 

 genus there is a large inflation of the base of the stem, either at the surface or 

 just below the surface of the soil. In gums (E. rostrata, leucoxylon, viminalis, 

 &c.) this is eventually outgrown; but in the mallees {incrassata, uncinata, &c.) 

 it persists and increases in size proportionately with the development of the 

 branches which are emitted from it — in the mallee this rudely globose bole is partly 

 subterranean. " The umbrella-like disposition of the foliage of the taller mallees 

 may be largely incidental to overcrowding, though it would seem to be an inherited 

 character, as it is fairly pronounced in them when they are distinctly separated 

 from one another." Tins classification is chiefly of practical use in Professor 

 Tate's own State (South Australia) and in Western Australia. 



It is, however, very difficult to group the species according to habit. Some 

 are dwarf in their typical forms, but under different circumstances they take on 

 a larger growth. Then, speaking generally, such species as are found in damp 



* Tate, R. — "A Review of the characters available for the classification of the Eucalypts, with a synopsis of the 

 species arranged on a earpological basis." 



t Luehmann. J. G. — " A short diehotomous key to the hitherto known species of Eucalyptus." 



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