(R.T.B. & H.G.S., in Euc. and their Ess. Oils, 1st Edit. 1902, p. 32.)

Flooded Gum

Systematic. - The herbarium material of this tree is altogether coarser than that of its allied species E. saligna. The leaves are large and broad, and generally dry a fresh, green colour, with a whiteness near the mid-rib, and a pale under surface. Branchlets angled. Peduncles flattened, about 6 lines long, bearing generally over six flowers, pedicel 4 lines long. Calyx 2 lines in diameter, tapering into the pedicel; operculum hemispherical, acuminate.

Fruit. - Uniformly pear-shaped, on a short thick pedicel, or sessile, glaucous, sometimes angled ; rim thin, and countersunk; valves exserted, mostly obtuse (only exceptionally acute as shown in fig.), white; about 3 lines in diameter.

Habitat. - Coastal districts of New South Wales and Queensland.

REMARKS.--It has been customary in the past to include botanically under the species (E. saligna) two trees known vernacularly as " Blue " and " Flooded " Gum respectively, but in this work the two are separated, the latter being placed as a variety of the former under the varietal name of pallidivalvis. The timbers of the two are only distinct as regards texture. The fruits of the variety are fairly constant throughout the area of distribution-the exserted white valves and glaucous calyx being very characteristic. As its physical characters connect it so closely to E. saligna we prefer to let it remain as a variety.

Mr. Maiden has raised it to specific rank, under the name of E. grandis, Proc. Roy. Soc, N.S W., vol. iii., p. 501

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Lismore, N.S.W., in July, 1900. The yield of oil was 0.26 per cent. The crude oil was dark red in colour, due to the action of the phenols on the iron derived from the still. It had a strong and somewhat unpleasant odour, evidently due to the presence of aldehydes, acids, and esters. The principal constituent of this oil is dextro-rotatory pinene, proved by its chemical reactions. A small quantity of cineol was detected, but less than 5 per cent. in the second fraction. Esters were present in some quantity, one of which was the valeric acid ester. Phellandrene does not occur in this oil, but free alcohols are present.

The crude oil had specific gravity at 150 C. = 0.8921; rotation not taken, the oil being too dark; refractive index at 200 = 1.4703, and was soluble in 7 volumes 80 per cent. alcohol. The saponification number for the esters and free acid was 28.9.

On rectification 2 c.c. distilled below 1550 C. (corr.). Between 155-1670, 67 per cent. distilled; between 167-2240, 18 per cent. came over; and between 224-2580, 7 per cent. distilled, which was very acid. These fractions gave the following results :-

Material of this species for distillation was obtained from the following localities in N.S.W.-Lismore, 23rd July, 1900; Tumbulgum, 15th September, 1900; Bulahdelah, 3rd September, 1900; and Barber's Creek, 17th March, 1899. The oils from all this material were practically identical in all their characters, as can be seen from the following table: -

The fractions, from those oils redistilled, were identical in each case, so that the results show a remarkable constancy with the several samples. The oil from Bulahdelah, for instance, when compared with that obtained nearly two months earlier from Lismore, is worthy of note. The amount of oil distilling below 167° C, the rotations and specific gravities of the several fractions, the saponification number for the esters, together with the solubility in alcohol, all go to show this close agreement. The nitrosochloride was prepared with the pinene, and this melted at .103-104° C. Although the oil of this form of E. saligna contains so much pinene, yet it scarcely falls into the group insoluble in 10 volumes of 80 per cent. alcohol; this peculiarity must, therefore, be due to the esters, and to the free alcohol, because the amount of cineol present is too small to influence the solubility. The crude oils of all our samples formed clear solutions with either 7, 8, or 9 volumes 80 per cent. alcohol.

To determine the approximate amount of free alcohol in the oil of this species a portion of the Lismore oil was acetylated in the usual way, carefully freed from acid and saponified. The saponification number had then increased to 56.04, so that the amount of alcohols present is represented by the saponification number 27.14. The esterised oil had a distinct odour of amyl-acetate. Although amyl-alcohol was present in combination as well as in the free condition, yet, it may be that a portion was also in combination with the valeric acid as an ester. If this is so, then the amyl-alcohol previously determined in the oil of E. globulus might have been derived from a similar ester.

The mixed oils of the above tabulated samples were kept in the dark, and in October, 1919, or nineteen years afterwards, the sample was again analysed. But little alteration had taken place during all that time, thus again illustrating the great stability of the pinene Eucalyptus oils. The specific gravity of the crude oil at 15° C. was 0.8950. On rectification 36 per cent. distilled below 160°, 76 per cent. below 180°, and 82 per cent. below 190°.

The portion distilling below 190° C. had specific gravity at 15° = 0.8749; rotation aD + 30.8°, and refractive index at 20° = 1.4652.