

173. Eucalyptus citriodora. 



(Hook., Mitch., I rop. Austi ., 

 Citron-scented Gum. 



Systematic. A large tree with a smooth, whitish bark. Leaves lanceola 

 up to 6 inches long and 9 lines wide, acuminate, not shining; venation finel} 

 marked, lateral veins numerous, oblique, | >;■ r;- lh 1 or slightly spreading, intra 

 marginal vein very slightly removed from the edge, which is more or less irregulai 

 Flowers numerous in axillary panicles. Calyx tube hemispherical to slightlj 

 cylindrical, about 2. lines in diameter, pedicel under 2 lines long; operculum 

 hemispherical, umbonate. 



Fruit. Ovoid, truncate, contracted at the edge; 

 rim thin; valves opening downwards; 

 under 4 lines in diameter and 6 lines long. 



Only n< 7 ith difficulty from E. maculata. 



Habitat. North coast district oi Queen land. 



REMARKS. The above is the localitj as a1 presenl known oJ tins species. Sir T. Mitchell collected 



his specim inland a1 Bee mr\ ( reek, Mantua Downs, and "Sir William Hookei named tins Eucalypt 



(although witho oj fruit) from the deliciously fragranl lemon-like odour, which exists in the drj as well 



as in the recent state." (Mitch ["rop \n i 235.) hie term " Citron-scented Gum " is now applied to a Coast 



with a smooth white bark, and 1 largely cultivated. It is no1 the onlj Eucalyptus possessing an aroma oi 



this character in its oil, as this als urs in the North Queensland " Ironbark," I Staigeriana F.v.M. Whether 



Mitchell's tree is botanically identical with that on the 1 oast and the one to whii h the name is now applied rem; ins 

 to In- proved, for, . 3 stated above, the spei ies was established on the leaves and chemical constituents alone. 



ESSENTIAL OIL. The oil of this species of Eucalyptus consists almost 

 entirely of the aldehyde citronellal, with from 5 to id per cent, of other bodies, 

 in< luding a small quantity "I ester, a little alcohol, perhaps geraniol or citronellol, 

 .in'! ,1 very small quantity oi a terpene. It has no resemblance to that distilled 

 hi. in the leaA es 1 >i E. maculata. 



This Eucalypl is essentially a Queensland one, growing quite extensively in 

 the Gladstone District, but il readily lend-, itself to cultivation in other parts, end 

 grows quite well in the Sydnej District. The species is quite stabilised, so that 

 the oil always shows comparative constancy, no matter where the irees are grown, 

 li also -how-, considerable vitality, end we have been informed by a gentleman 

 who know- the district well, that on the Herberton Range to the north 

 "i Cairns there are m n\ hundred- oi acres where E. citriodora grows plentifully. 

 When he v there the trees had been cut down for mining purposes, but a great 

 quantity of " suckers " had 1 ome up, .'wi] consequently an abundance of leal was 

 liable. He distilled oil from (hi- material and found it oi excellent quality. 



We were unable to ob1 tin leaves from Queensland for distillation purpose 

 but have investigi ted the oil commercially distilled their. it was found to be 

 in agr< emi nt w ith the oil we distilled from a cultivated tree in Sydney. I ha1 the 

 1 on- 1 h in ion of the oil from 1 ultivated trees is similar to that distilled from material 

 growing in its native habital can be seen from the results of the analyses we submit 

 herewith. 



