(T. B. Moore, in Roy. Soc, Tas., 207, 1886.) Brown Gum.

Systematic. - A large tree, attaining a height of 200 feet. Bark scaly at base, smooth above, reddish in colour, often blotched. Abnormal leaves, usually opposite, rounded or oval, crenulate, mucronate, sometimes cordate, sessile or shortly petiolate, averaging about 2 inches long and 11 /2 inch broad. Normal leaves ovate to lanceolate, thick, shining; venation not pronounced, intramarginal vein somewhat removed from the edge, lateral veins inclined at an angle of about 300 to the mid-rib. Flowers sessile, usually in threes, short, broad, angular, on axillary peduncles about 2 lines long. Buds reddish in colour; calyx tube almost hemispherical, flanged, about 2 lines long; operculum domed at first, surmounted by a blunt point.

Fruit. - Compressed, hemispherical, or semi-ovoid, sometimes ridged; rim convex; valves thick, exserted; about 3 lines long and 4 lines in diameter.

The nearest in form is perhaps E. Baeuerleni or even E. unialata.

Habitat. - Tasmania, high situations.

REMARKS. - Mueller, and now later systematists are inclined to regard this species as identical with E. vernicosa, and the oils do not assist much in their separation, hut otherwise we fail to detect any other common character. The leaves, buds, and fruits of E, vernicosa have no resemblance whatever to those of E. Muelleri. The timber and bark are different, and further, the latter is a tree and E. vernicosa a "Mallee."

When planted in other countries they both grow true to the original and show no variation or gradation into each other.

ESSENTIAL OIL. - Material of this species for distillation was obtained from Mt. Wellington, Tasmania, at an altitude of about 3,000 feet; it was collected in July, 1908. The principal constituent in the oil was cineol, together with a fairly large amount of pinene. Phellandrene was not present, nor was it to be expected, judging from the botanical features of the species. There was rather a large amount of ester for oils of this class, and this appeared to be largely geranyl-acetate, as it was mostly saponified in the cold with two hours' contact. The crude oil was of a light-amber colour, and had an odour resembling those belonging to the pinene-cineol group. Volatile aldehydes were present, but could be separated without difficulty on redistillation.

The yield of oil from leaves and terminal branchlets was 1.28 per cent. The crude oil had specific gravity at 150 C. = 0.9096; rotation aD +10-4°; refractive index at 200 = 1.4647, and was soluble in 4 volumes 70 per cent. alcohol. The saponification number for the esters and free acid was 15.3, while in the cold with two hours' contact it was 11.7.

On rectification, the usual amount of acid water and volatile aldehydes came over below 166° C. (corr.), at which temperature the oil commenced to distil. Between 166-173°, 44 per cent. distilled; between 173-195°, 45 per cent.;

the temperature then quickly rose to 2250, and between that temperature and 252°, 5 per cent distilled. These fractions gave the following results: -

the cineol was determined in the portion distilling below 195° by the resorcinol method; the result was 60 per cent. when calculated for the crude oil. By the rapid phosphoric acid method it was 57 per cent. when calculated lor the crude oil.

The results obtained with this oil, and also with those of E. urnigera and E. vernicosa show them to belong to the better class of cineol-pinene oils, but they suffer from the defect of containing rather too much pinene, consequently their specific gravities are reduced below 0.91. However, more than half the rectified oils of these species consists of cineol, and the supposed defect of specific gravity could easily be remedied if desired.

It is interesting to notice how closely the oil of this species agrees with that of E. vernicosa, as may be seen from the following table. The difference in yield is due to the coarser stems and less expansive leaves of E. vernicosa: -

The results of this investigation were published by us in the Proc. Roy. Soc, Tasmania, October, 1912.