Sept. 20, 1877J 



NATURE 



443 



REMARKABLE PLANTS 



IV. — The Blue Gum Tree {Eucalyptus globulus, 



Labil.). 



SO much attention has been directed during the last 

 few years to the various remarkable virtues attributed 

 to this tree, that an exaggerated idea of its value may 

 exist in many minds. Sufficient has, however, been 

 established on irrefragable authority to justify a brief 

 account, in this series of papers, of the known proper- 

 ties and qualities of the Eucalyptus. We rely for a con- 

 siderable proportion of our (acts on a lecture delivered 

 before the Royal Botanic Society of London in 1874, by 

 Prof. Bentley, and on the account of the tree in Bentley 

 and Triinen's " Medicinal Plants," part 15, our illus- 

 tration being also, to a considerable extent, copied from 

 that in the latter work. 



The genus Eucalyptus is a large one, numbering about 

 150 species, and belongs to the natural order Myrtaceas, 



distinguished by the number of trees and shrubs included 

 in it which yield aromatic properties. The species are 

 all, with a few doubtful exceptions, natives of Australia or 

 Tasmania, and are known in the Colonies as " gum-trees" 

 and "stringy-bark trees." They are all evergreen trees, 

 several of them of enormous height. The one we are 

 describing, a native of Tasmania and temperate Australia, 

 is perhaps the most gigantic of them all, not unfrequently 

 attaining a height of upwards of 300 feet. 



The leaves vary remarkably according to the age of the 

 plant ; when it is young they are large, sessile, and oppo- 

 site, of a bluish glaucous- white coloar, and placed at 

 right- angles to the branches on which they grow, while 

 on older plants they are much narrower (as shown in the 

 drawing), alternate, bluish green, and, by a twisting of the 

 petiole, appear as if placed obliquely, or in the same 

 plane as the branches, with their flat surfaces lateral. Th ; 

 flowers are large and not very unlike those of the myrtle, 

 with a very large number of stamens, but differing in the 



Eucalyptus gloinlus (Blue Gum Tree). Branch with n 



(reduced) J 



absence of a corolla, the limb of the calyx becoming 

 detached when the flower opens in the form of a lid or 

 " operculum." 



The rapidity of the growth of this tree is one of its 

 most remarkable and valuable features. Although not 

 introduced into this country till the year 1856, and not 

 perfectly hardy here, except perhaps in the extreme 

 south-west, trees of a considerable size are not unfre- 

 quently seen. A specimen only two years old has flowered 

 this year in the Economic House at the Regent's Park 

 Botanic Gardens. In its native country it is stated that in a 

 grove planted only sixteen years, the average height of 

 the trees is seventy-two feet, and the girth of the stems 

 six feet ; while a tree ten years old presents the develop- 

 ment of a well-grown oak of a century. In fifty years 

 they are said to attain a height of from 160 to 200 feet, 

 and the trunk a circumference of from 50 to 60 feet 

 at the base. Even where the Eucalyptus is not indi- 

 genous, well-authenticated instances of a rapidity of 

 growth almost equalling this are on record in favourable 



climates. Mr. Thomas Hanbury states that near Mentone 

 a seedling planted in March, 1S69, was then three feet 

 high ; in 1874 it had reached forty-eight feet, and the 

 circumference of the trunk was three feet at three feet above 

 the ground. In Algeria the growth is no less astonish- 

 ingly rapid. The gigantic size of the trunk is combined 

 with a peculiarity of growth which greatly adds to the 

 value of the timber. It rarely sends out a branch till the 

 stem is 100 feet high, and Prof. Bentley states that 

 planks have frequently been cut 160 feet long, twenty 

 inches broad, and six inches thick. The timber is stated 

 to be at the same time remarkable for its hardness and 

 durability. 



This rapid growth renders the Eucalyptus an invalu- 

 able tree for planting in countries where deforesting has 

 been carried to so great an extent as to prejudicially 

 diniinish the rainfall ; and it has now been more or less suc- 

 cessfully cultivated for this purpose in France, Spain, Por- 

 tugal, Greece, Italy, Corsica, Algeria, Egypt, St. Helena, 

 Palestine, the uplands of India, Natal, other parts of 



