(R.T.B., Proc. Linn. Soc, N.S.W., 1900, p. 691, t. XLVI, fig. 5.) A Spotted Gum.

Systematic. - A fair-sized tree, with a dirty, flaky bark, which is occasionally smooth. Abnormal leaves ovate, lanceolate; normal leaves lanceolate, up to 6 inches long, and varying in breadth up to 9 lines, straight or falcate, not shining, of the same shade of green on both sides; petiole under 1 inch long; venation fairly well marked, veins oblique, spreading; the distinct, intramarginal vein removed from the edge. Oil dots numerous. Peduncles axillary, with few flowers (five to seven) in the head, occasionally only three. Calyx hemispherical, shortly acuminate.

Fruit. - Hemispherical to oblong; rim, together with the valves, domed and leaving only a slight aperture to the ovary, or it is sometimes thin and the valves exserted and wide-spreading.

Very difficult to determine from E. viminalis in most instances. The specimen depicted shows the less domed or irunncate rim form.

Habitat. Mount Vincent, Hford; Oberon-road, O'Connell; Southern-road, Wingello; along the main Western-road, Blackheath, and Mount Victoria, New South Wales.

REMARKS. - In the field this tree might be confounded with E. viminalis, Labill., or E. hosmaslcma, Sm., as both these Kmalypts have a smooth bark, which, however, in this species never has the horizontal (insect) markings almost invariably occurring on E. viminalis, nor the "scribbles" found on E. hamastoma. It has almost similarly shaped leaves in all its stages of growth, whilst the abnormal leaves of E. viminalis are narrow, cordate-lanceolate, sessile. The fruits differ little from those of E. viminalis in shape, rim, and direction of valves. The trees, too, are not found near water, as obtains almost invariably with E. viminalis, but on dry, stony ridges. It differs also from that species in the constituents of its oil. It resembles E. maculosa, R.T.B., in the shape of the fruits, but differs from it in timber and bark. The specific name refers to the copious exudation of a milky substance from the stem when the tree is cut at certain seasons of the year.

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained at Ilford, New South Wales, in September, 1899. The yield of oil was 0.54 per cent. The crude oil was red in colour, and had a turpentine-like odour, far from pleasant. Pinene was the chief terpene and phellandrene was absent. Cineol was only present in small amount, about 10 per cent. It is a terpene oil, and of little commercial value. The crude oil had specific gravity at 15o C. = 0.8826; rotation nil; refractive index at 20o = 1-4845, and was soluble in 2 volumes 80 per cent. alcohol. The saponification number for the esters and free acid was 8.56. The presence of cymene was indicated.

On rectification no less than 90 per cent. distilled between 165-188o C. This rectified oil had specific gravity at 15o = 0.8788; and rotation aD - 1.16°.

Material of this species for distillation was also obtained from Braidwood. New South Wales, in October, 1898. The results with this oil were in agreement with that distilled from the Ilford leaves. The yield of oil was 0.57 per cent.

On rectification 88 per cent. distilled below 188o C. The crude and rectified oils gave the following results: -

The saponification number for the esters and free acid was 11.5, and it was soluble in 5 volumes 80 per cent, alcohol.

The mixed oils of the above had been kept in the dark, and in October, 1919, the sample was again analysed. Not much alteration had taken place in the character of the oil during the 20 years it had been stored, with the exception that the cineol had perhaps increased a little. The crude oil and traction gave the following results. 88 per cent, of the oil distilled below 190° C.: -

The cineol was determined by the resorcinol method in the redistilled portion, and calculated for the crude oil; the result was 22 per cent.

The cymene was determined in the portion distilling below 190° C. The cineol was first removed by combining it with phosphoric acid, afterwards shaking the uncombined oil with 50 per cent. resorcinol. It was then washed, dried and distilled, the required fraction being separated. This had specific gravity at 15o C. = 0.8632; rotation nil; refractive index at 20o = 1.4835. A portion was oxidised by potassium permanganate in the usual way. The finally prepared acid melted at 155-156o C, thus indicating p-oxyisopropylbenzoic acid, the oxidation product of p-cymene.