314 



and pedicels absent, or nearly so. Buds small, the operculum and calyx of 

 approximately equal size, the former but very slightly conical, up to eight in the 

 head, but perhaps five on the average. 



Fruit. Hemispherical, slightly dilated at the rim, 

 which is well defined ; valves usually three, 

 but rarely four, scarcely exserted, 2 to 3 

 lines in diameter. 



These so much resemble those of E. Rodwayi that some 

 systematists have confounded the two. They are also 

 very close in shape to E. aggregata and E. acaciaeformis. 



Habitat. Confined to the counties of Camden and Argyle, New 

 South Wales, as far as known at present. Prefers 

 swampy or low-lying land, or the banks of streams ; 

 Mittagong, Bowral, and Moss Vale, New South Wales. 



REMARKS. Bentham thought this species had an affinity with E. viminalis, but, except in the abnormal 

 and mature leaves, the affinity does not appear to be marked. Its narrow abnormal leaves and small fruits should 

 prevent its confusion with E. Bridgesiana, R.T.B. It is a very distinct species in the field, and could not be 

 confused with other Eucalypts. The odour of the leaves when crushed at once distinguishes this species from all 

 others with the exception of that of E. acervula. The remarks of the authors of the species (loc. cit.) on E. diversi/n/in 

 apply to their E. rubida, and not to this species. 



ESSENTIAL OIL. In the year 1900, the discovery was made that the 

 oil of Eucalyptus Macarthuri was of quite an . exceptional character, in that it 

 consisted very largely of 'geranyl-acetate and free geraniol. (See paper by one 

 of us, Proc. Roy. Soc., N.S.W., Nov., 1900.) Since that time a considerable amount 

 of work has been done upon the oil of this species, and it has always been found 

 to be in agreement with the results originally published. The species has become 

 of importance for the production of an oil for perfumery purposes, and is now 

 being cultivated in Victoria. The species grows to a large size and has a thick 

 aromatic bark, which also produces an essential oil similar in composition with 

 that from the leaves. (See Proc. Roy. Soc., N.S.W., October, 1916.) The oil 

 is present in sufficient quantity in the bark to allow it to be profitably distilled. 

 The " suckers " from the stumps of the fallen trees >grow rapidly, and produce 

 an oil equal in value to that from the mature leaves, so that the process of distilling 

 oil from the bark is not so wasteful as might at first sight appear. The bark 

 oil, however, does not contain crystallised eudesmol, which substance is such a 

 pronounced constituent in the leaf oil. The higher-boiling portions of the leaf- 

 oil contained sufficient eudesmol to cause the third fraction to crystallise to 

 a solid mass soon after distilling. Neither phellandrene nor cineol occur in the 

 oil of this species, the small amount of terpene being dextro-rotatory pinene. 



The results from a very large number of analyses on the oil of this species 

 show that 60 per cent, of geranyl-acetate, saponifiable in the cold with two hours' 

 contact with alcoholic potash, is the minimum at any time of the year. The oil 

 of E. Macarthuri seems to follow the general rule for Eucalyptus oils by containing 

 less terpene during the winter months, with a corresponding increase in ester. 

 The oil from abnormal leaves contains even more ester than does that from the 

 mature leaves, while that from leaves of two years old seedlings is also richer in 

 geranyl-acetate than the oil from old leaves. 



The crude oils are usually red in colour ; as explained previously this red 

 colour is due to the free acid in the oil attacking the iron of the still, and this, 

 acting on the phenols, causes the oil to become red. The free geraniol in the oil 

 was less when the ester content was high, and greater when the amount of ester 



