232 A CONTRIBUTION TO ETC. 



resembling some of the half barked varieties of the White Gum 

 (E. Jiosmastoma), but having larger flowers and an ovoid-truncate 

 seed-vessel,sometimes more than half an inch long. Mr. Backhouse 

 procured flowering specimens of this gum in Bargo Brush, and 

 from the same quarter Sir William Macarthur obtained specimens 

 of the wood. The wood is of very little value, being similar in 

 character to that of the White Gum. If it were not for the 

 different shape of the seed vessel, I should regard IE. obtusiflora, 

 as a mere variety of E. hcemastoma. This gum occurs on the Blue 

 Mountains. 



(3.) E. pilularis or Blackbut is one of the largest and most 

 valuable species of the genus. At Bulli, a Blackbut was recently 

 found to be more than forty-six feet in circumference at five feet 

 from the but, and 150 feet to the first branches. The wood is 

 excellent for house carpentry, ship-building, and indeed for any 

 purpose where strength and durability are required. From ex- 

 periments made at the Universal Exhibition, held in Paris in 1855, 

 it was ascertained that the specific gravity of Blackbut is O897, 

 and that next to the " Eough barked Iron Bark," no species of 

 Eucalyptus is known to bear a greater crushing strain in the 

 direction of the fibre. This tree prefers a good soil, and is rapid 

 in its growth. Mr. Bent-ham places the " White Mahogany" (Jt!. 

 acmenoides) with the Blackbut, expressing, however, some doubt 

 as to the propriety of regarding the former as a mere variety. 

 The White Mahogany has a persistent bark similar to Stringy 

 Bark, though not so fibrous, and by some collectors, it has evi- 

 dently been mistaken for that tree. No one who has had an 

 opportunity of seeing the Blackbut and White Mahogany grow- 

 ing in proximity to each other, would regard them as allied species, 

 for they differ in bark, foliage, and inflorescence, whilst the wood 

 varies in grain and colour, 



(4.) E. bicolor comprises several varieties of what workmen 

 call " Bastard Box" or " Yellow Box." There is a great similiarity 

 between the flowers and seed vessels of this species, and those of 

 the narrow leaved variety of Iron Bark. Hence it is not sur- 

 prising to find tliat Mr. Bentham associates some of Caley's 

 specimens of Iron Bark with the Bastard Box. I suppose this 

 species derives its specific name from the grey and white patches 

 on the bark, which in some places, give it the appearance of a 



