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

Systematic. - A medium-sized tree, with a smooth, white bark. Leaves lanceolate, generally under 6 inches long, mostly narrow, falcate and thin, rarely over 12 lines wide; venation distinct, intramarginal vein removed from the edge, lateral veins oblique, spreading. Peduncles axillary, rarely forming panicles, slender, flattened, under twelve flowers in the head, pedicel almost filiform, 2 lines long. Calyx under 2 lines in diameter; operculum hemispherical, shortly acuminate.

Fruit.-Hemispherical; rim red, broad in comparison to the size of capsule; valves slightly or not exserted; about 2 lines in diameter.

They are similar with those of E. hæmastoma, var. micrantha, and care is required not to confound botanically the two species.

Habitat. Tableland and Coast district of Eastern Australia.

REMARKS. This species is very constant in its specific character throughout its geographical distribution, and shows no disposition to variation. Mueller synonytnised it with E. hamastoma, Sm., as a variety, but it only resembles that species in the shape of the fruit. The leaves, fruits, oil, and Umbel easily distinguish it from E. hæmastoma of Smith. This is not E. hæmastoma, var. micrantha which is a true varietal form of the species.

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Cow Flat, Bathurst, N.S.W., in March, 1901. The yield of oil was 0.72 per cent. The crude oil was of a dark amber colour; and had an odour reminding of peppermint, although piperitone could only be present in very small quantity. It was fairly rich in cineol; pinene was present, but phellandrene not detected. The presence of a high boiling constituent which had a high rotation to the right was well shown; this is the liquid form of eudesmol. The oil of this species differed greatly from that of E. hcemastoma, of Smith, the "Scribbly Gum" of the coast, and also from that of "Scribbly Gum" growing around Lawson, and other places on the Blue Mountains, N.S.W.

The crude oil had specific gravity at 15° C. = 0.9215; rotation aD. + 7.2°; refractive index at 20° = 1.4684, and was soluble in 1 1/2 volumes 70 per cent, alcohol. The saponification number for the esters and free acid was 7.95.

On rectification, about 1 per cent. of acid water and volatile aldehydes came over below 165o C. (corr.). Between 165-1830, 69 per cent, distilled; between 183-233°, 14 per cent, came over, and between 233-280°, 11 per cent, distilled. These fractions gave the following results: -

The cineol determined in the first fraction by the phosphoric acid method was 49 per cent. (O.M.), indicating about 40 per cent, in the crude oil.

Material of this species had previously been sent from Bungendore, N.S.W., in March, 1899. The oils were practically identical in every respect, with the exception that a little more pinene was present. The specific gravity of the crude oil at 15° was 0.9168. Below 183°, 78 per cent, distilled; between 183-240°, 9 per cent., and between 240-280°, 7 per cent. The crude oil was soluble in 1 1/4 volumes 70 per cent, alcohol. The fractions gave the following results:- -

The cineol determined in the large fraction by the phosphoric acid method was 52 per cent. (O.M.), indicating about 42 per cent, in the crude oil.

On the completion of the analyses, the two oils were mixed and stored in the dark. In August, 1919, the sample was again analysed. After twenty years but little alteration was observed in the oil of this species; and on rectification, 80 per cent, distilled below 190° C. The results with the crude and rectified oils were as follow: -

The cineol was determined by the resorcinol method in the large fraction and calculated for the crude oil; the result was 64 per cent. By the phosphoric acid method it was 55 per cent.

In November, 1913, material of this species for distillation was received from Cooma, N.S.W. The yield of oil was 0.52 per cent. The results agree very closely with those previously obtained for the oil of this species. Phel-landrene was absent, but pinene was present, and also a fair amount of cineol. Crystallised eudesmol was not detected, although the liquid form was present in some quantity. The crude oil had the following characters: -

Specific gravity at 150 C. = 0.9243; rotation aD + 9.8°; refractive index at 200 C. s= 1.4683, and was soluble in 1 1/2 volumes 70 per cent, alcohol.

The cineol was determined by the phosphoric acid method; the result was 45 per cent.

The high-boiling dextro-rotatory alcohol. - Crystallised eudesmol has not at any time been detected in the oil of this species under ordinary conditions, but efforts to determine the identity of the alcohol resulted in the reversion of the liquid to the crystallised form. The mixed oil of this species, which had been stored for nearly twenty years, was taken for this investigation.

The saponification number for the oil was 6.13; after acetylation, it was 38.55. This result is equal to 13 per cent of free alcohol considered as C15H25OH.

800 c.c. of the crude oil gave 160 c.c. boiling above 1920 C, equal to 20 per cent.; 157 c.c. of the high-boiling portion when distilled under reduced pressure, gave the following fractions: -

The last two fractions gave the following results:-

Fraction No. 2, on standing about fourteen days, formed a buttery-like mass, and had commenced to crystallise. Fraction No. 3 commenced to crystallise after standing overnight, and eventually became wholly crystalline.

Both fractions were then utilised for the preparation of the pure eudesmol. The melting point of this was 79-80° C, and in a 12 per cent, chloroform solution, gave specific rotation [a]D + 33.58°.

See also the article on eudesmol in this work, where the properties and peculiarities of this interesting substance are dealt with.