AND THEIR ESSENTIAL OILS. 11 



E. paludosa, R. T. B., has a smooth bark, whilst E. 

 acervula, Sieb., has mostly a rough bark, and could per- 

 haps on occasions be classified with the hemiphloiae group 

 of Eucalypts. 



' The tree has usually a very bushy top, and the leaves 

 are of rather a pendulous growth." (L. G. Irby.) E. 

 paludosa is a fine typical tree, with stout outstretching 

 branches and a straight stem . The ' ' sucker ' ' leaves are 

 very different in appearance, shape, and colour from those 

 of E . Gun nil, from which species it also differs in the num- 

 ber of flowers in the umbel, bark, timber, and chemical 

 constituents. 



From our investigations it would appear that the chief 

 botanical differences between E. actrvula, Hook, f., and 

 E. paludosa, R. T. B., are the timber and bark and the 

 chemical constituents. 



E. acervula timber is harder, closer grained, and 

 altogether superior to that of E . paludosa. 



CHEMISTRY. 



Essential Oil. This material for distillation was col- 

 lected at Hobart in April, 1912. The average yield of oil 

 was 0*212 per cent. The crude oil was reddish in colour, 

 and had an odour resembling geranyl-acetate, which, 

 together with its appearance, reminded one of the oil of 

 A T . Macarthuri of New South Wales. The chief consti- 

 tuents present were dextro-rotatory pinene, laevo-rotatory 

 phellandrene, eucalyptol, geranyl-acetate, free geraniol, 

 together with a small amount of an undetermined alcohol, 

 and its ester, and what is more important from a scientific 

 point of view, a solid paraffin-like stearoptene, and a paraf- 

 fin, liquid at ordinary temperatures. The presence of such 

 a stearoptene in Eucalyptus oils has not previously been 

 recorded, but it does not appear to be peculiar to this 

 species, for traces of it in the oils from two New South 

 Wales Eucalypts have already been detected. It most 

 probably belongs to the C' n H. 2n + 2 group, as it is a 

 saturated substance. This solid aliphatic stearoptene is 

 related to a similar substance found in Rose oil, although 

 melting at a higher temperature, and it is remarkable that 

 the principal alcohol in both Rose oil and in the oil of this 

 Eucalypt is geraniol. The oil of E . Macarthuri, however, 

 does not contain it. Similar paraffins, with varying melt- 

 ing-points, have been isolated from the oils of a few other 

 plants, and in some cases from the oils of their leaves. This 

 stearoptene, from this Eucalypt, is without doubt from the 



