(RT.B., Proc. Linn. Soc, N.S.W., 1898, p. 167, t. VI.) Yellow Gum, Swamp or Flooded Gum,

Systematic. - A tree from 60 to 100 feet high, with a diameter from 2 to 3 feet. Bark brown at the butt, bluish-white on the trunk and main branches, and yellow on the smaller branches and limbs, decorticating into long ribbons of 30 feet or more, suspended from the forks and trunks of the trees. The lower young leaves opposite, sessile ovate-acuminate, rarely cordate; the upper ones petiolate, irregularly opposite, lanceolate, coriaceous, often shining, and of a yellowish-green on both sides; venation distinct. Normal leaves lanceolate-acuminate, varying in length up to 8 or 9 inches, coriaceous, slightly shining on both sides, drying a yellowish tinge; lateral veins oblique, fairly numerous and equally prominent on both sides, but in some instances scarcely visible, the intramarginal vein removed from the edge in the broader leaves, but closer in the narrower ones. Peduncles axillary, under 1/2 inch long, flattened, with seven to ten sessile flowers. Calyx tube 3 lines long; operculum conical, shortly acuminate, much shorter than the calyx tube.

Fruit.-Fruit shortly pedicellate, conical, truncate, with a flange just below the rim, three or four celled; valves not exserted; under 5 lines in diameter and about 4 lines in length.

Care is required not to confound them with those of E. camphora, a smaller fruit with valves exserted, oi E. acervula.

Habitat. - Coast District (southern half), New South Wales; Victoria.

REMARKS. - The systematic position of this species is later dealt with in our paper on Euc, Tas. Roy. Sic, 1912. in addition to remarks given in our Euc. and their Ess. Oils, 1st Edit.

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Barber's Creek, New South Wales, in June, 1898. The yield of oil was 0.24 per cent. The crude oil was red in colour, and had a turpentine-like odour. A somewhat large amount of pinene was present, while the higher boiling portion consisted largely of the sesquiterpene. Phellandrene was not detected. Cineol occurs in this oil, although not in large amount. The esters consisted largely of a valeric acid ester and geranyl-acetate. The portion distilling above 250° was of a bright blue colour.

The crude oil had specific gravity at 15° C. = 0.9056; rotation aD + 10°; refractive index at 20o = 1.4716, and was soluble in 1 volume 80 per cent. alcohol. The saponification number for the esters and free acid was 18.4.

On rectification 2 per cent. distilled below 164o C. (corr.). Between 164-172o, 47 per cent. distilled; between 172-250o, 34 per cent. came over, and between 250-265°, 12 per cent, distilled. These fractions gave the following results: -

The cineol, determined by the phosphoric acid method in the second fraction, indicated 23 per cent. in the crude oil (O.M.).

Another sample of the oil of this species was obtained from Barber's Creek in May, 1898. This oil agreed with the above sample except that the yield was less, but in ester content, rotations for the several fractions and other physical characters, as well as in the amount of cineol present, the oils were practically identical.

The first sample of oil had been kept in the dark, and in September, 1919, was again analysed. Very little alteration had taken place in the oil during the 21 years it had been stored, except that the specific gravity had increased a little. On distillation 80 per cent. came over boiling below 190o C. The crude oil and fraction gave the following results: -

The cineol was determined by the resorcinol method in the portion distilling below 190°; when calculated for the crude oil the result was 42 per cent. By the rapid phosphoric acid method it was 26 per cent. when calculated for the crude oil.